Cadmium immobilization in soil using phosphate modified biochar derived from wheat straw

The phosphate-modified biochar (BC) immobilizes cadmium (Cd), yet little is known about how phosphate species affect Cd detoxification in contaminated soils. We developed phosphate-modified biochar through the pyrolysis of wheat straw impregnated with three types of phosphate: mono‑potassium phosphate (MKP), dipotassium hydrogen phosphate (DKP), and tripotassium phosphate (TKP). The Cd adsorption mechanism of modified biochar was investigated by biochar characterization, adsorption performance evaluation, and soil incubation tests. The results demonstrated that the efficiency of biochar in immobilizing Cd2+ followed the order: TKP-BC > DKP-BC > MKP-BC. The TKP-BC had the highest orthophosphate content, the fastest adsorption rate, and the largest adsorption capacity (Langmuir) of 257.28 mg/g, which is 6.31 times higher than that of the unmodified BC (CK). In contrast, pyrophosphate was predominant in MKP-BC and DKP-BC. The primary adsorption mechanism for Cd2+ was precipitation, followed by cation exchange, as evidenced by the formation of CdP minerals on the BC surface, and an increase of K+ in solution (compared to water-soluble K+) and a decrease of K+ in the biochar during adsorption. Desorption of Cd from the TKP-BC after adsorption was 9.77 %-12.39 % at a pH of 5-9, much lower than that of CK. The soil incubation test showed the diethylenetriaminepentaacetic acid extracted Cd of TKP-BC, MKP-BC, and DKP-BC was reduced by 67.93 %, 18.41 % and 31.30 % over CK, respectively. Using the planar optodes technique, we also found that TKP-BC had the longest effect enhancing in situ soil pH. This study provides a theoretical basis for developing heavy metal pollution control technology using green remediation materials and offers insights into the remediation mechanisms.

New insights into biochar ammoniacal nitrogen adsorption and its correlation to aerobic degradation ammonia emissions

One of the technical barriers to the wider use of biochar in the composting practices is the lack of accurate quantification linking biochar properties to application outcomes. To address this issue, this paper investigates the use of ammonia nitrogen adsorption capacity by biochar as a predictor of ammonia emission during composting in the presence of biochar. With this in mind, this work investigated the use of ammonia nitrogen adsorption capacity of biochar when mixed with solid digestate, and the reduction in ammonia emissions resulting from the addition of biochar during aerobic degradation of solid digestate. A biochar synthesized at 900 °C, another synthesized at 450 °C, and two derivatives of the latter biochar, one chemically modified with nitric acid and the other with potassium hydroxide, were tested. This study concluded that the chemical characteristics of the biochar, including pH and oxygen/carbon atomic ratio, had a greater influence on the adsorption of ammonia nitrogen than physical attributes such as specific surface area. In this regard, nitric acid modification had superior performance compared to hydroxide potassium modification to increase biochar chemical attributes and reduce ammonia emissions when applied to aerobic degradation. Finally, a significant linear correlation (p-value < 0.05, r2 = 0.79) was found between biochar ammonia nitrogen adsorption capacity and ammonia emissions along composting, showing the potential of this variable as a predictive parameter. This study provides insights for future explorations aiming to develop predictive tests for biochar performance.

Upgrading recovered carbon black (rCB) from industrial-scale end-of-life tires (ELTs) pyrolysis to activated carbons: Material characterization and CO2 capture abilities

The current study presents for the first time how recovered carbon black (rCB) obtained directly from the industrial-scale end-of-life tires (ELTs) pyrolysis sector is applied as a precursor for activated carbons (ACs) with application in CO2 capture. The rCB shows better physical characteristics, including density and carbon structure, as well as chemical properties, such as a consistent composition and low impurity concentration, in comparison to the pyrolytic char. Potassium hydroxide and air in combination with heat treatment (500-900 °C) were applied as agents for the conventional chemical and physical activation of the material. The ACs were tested for their potential to capture CO2. Ultimate and proximate analysis, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), Raman spectroscopy, thermogravimetric analysis (TGA), and N2/CO2 gas adsorption/desorption isotherms were used as material characterization methods. Analysis revealed that KOH-activated carbon at 900 °C (AC-900K) exhibited the highest surface area and a pore volume that increased 6 and 3 times compared to pristine rCB. Moreover, the AC-900K possessed a well-developed dual porosity, corresponding to the 22% and 78% of micropore and mesopore volume, respectively. At 0 °C and 25 °C, AC-900K also showed a CO2 adsorption capacity equal to 30.90 cm3/g and 20.53 cm3/g at 1 bar, along with stable cyclic regeneration after 10 cycles. The high dependence of CO2 uptake on the micropore volume at width below 0.7-0.8 nm was identified. The selectivity towards CO2 in relation to N2 reached high values of 350.91 (CO2/N2 binary mixture) and 59.70 (15% CO2/85% N2).

Effects of erosion and abrasion on resin-matrix ceramic CAD/CAM materials: An in vitro investigation

The aim of the study was to evaluate the effects of erosion and abrasion on resin-matrix ceramic CAD/CAM materials [CERASMART (GC); VITA ENAMIC (VITA Zahnfabrik); Lava Ultimate (3 M)] in comparison to feldspar ceramic (VITABLOCS Mark II, VITA Zahnfabrik) and resin composite materials (ceram.x universal, Dentsply Sirona). Daily brushing and acid exposure were simulated using a brushing apparatus and a solution of 0.5 vol% citric acid. Microhardness, surface roughness, and substance loss were measured at baseline and after simulation of 1 and 3 years of function. All materials showed a decrease in microhardness after 3 years and an increase in surface roughness (Ra) after 1 and 3 years. The Ra increase was statistically significantly lower for the resin-matrix ceramics than for feldspar ceramic and similar to composite material. After 3 years, only feldspar ceramic showed no significant substance loss. In conclusion, resin-matrix ceramics demonstrate reduced roughening compared to feldspar ceramics, potentially improving restoration longevity by preventing plaque buildup, but differences in abrasion resistance suggest the need for further material-specific research. Future research should aim to replicate clinical conditions closely and to transition to in vivo trials.

Competitive encapsulation of multiple heavy metals by magnesium potassium phosphate cement: Hydration characteristics and leaching toxicity properties

Magnesium potassium phosphate cement (MKPC) is increasingly used in the solidification/stabilization (SS) of heavy metal (HM) pollutants. However, research on composite HM pollutants remains limited. In this study, four heavy metals (Pb/Zn/Cu/Cd) were individually and simultaneously introduced into MKPC systems with different magnesium/phosphorus (M/P) molar ratios. The introduction of HMs altered the extent of hydration and morphology of MgKPO4·6H2O. Among the MKPC pastes, those with M/P = 2 and 3 had the highest HM solidification efficiency and strength, respectively. The HM solidification efficiency of all specimens exceeded 99 %. In samples with M/P = 3, the codoping of four HMs slightly increased the M/P ratio, thereby increasing MgKPO4·6H2O content and enhancing strength. Pb could generate additional low-solubility precipitates, such as PbHPO4, Pb3 (PO4)2, Pb5 (OH) (PO4)3, and Pb (OH)2, which easily accumulated in pores and were encapsulated by MgKPO4·6H2O, leading to the highest solidification efficiency of Pb by MKPC. Pb and Cu could also form the composite phosphate products Pb2Cu (PO4)3 (OH)·4H2O, thus promoting the S/S effect of Cu. Therefore, the use of MKPC with M/P ratio of 2-3 for the S/S of complex pollutants containing Pb and Cu is a promising approach.

Efficacy and Rapidity of Potassium Hydroxide Mount and Modified Chicago Sky Blue 6B Stain with Potassium Hydroxide in Fungal Keratitis Detection

PURPOSE

To compare the efficacy and rapidity of direct microscopic detection of fungal elements from corneal ulcers between 10% potassium hydroxide (KOH) and 1% Chicago Sky Blue 6B (CSB) in 10% KOH (CSB-KOH).

METHODS

Thirty patients with clinically suspected fungal keratitis were recruited. Participants with impending corneal perforation were excluded. Two slides were smeared with corneal ulcer scrapings from the ulcer's edge and base for comparison of fungal staining solutions. One slide was infused with KOH, and the other slide was filled with CSB-KOH. Additional scraping was collected for inoculation on Sabouraud dextrose agar for fungal culture. The sensitivity, specificity and rapidity of both stainings were analyzed.

RESULTS

The sensitivity of fungal culture, KOH, and CSB-KOH were 43.75% (95% confidence interval [CI], 19.75%-70.12%), 62.50% (95% CI, 35.43%-84.80%), and 87.50% (95% CI, 61.65%-98.45%), respectively. The specificity were 100% (95% CI, 69.15%-100%) of both stainings and fungal culture which analyzed from 16 fungal keratitis cases by laboratory and clinical diagnosis. Mean CSB-KOH examination time was quicker than KOH with the mean time difference of 5.6 minutes (95% CI, 3.22-7.98 minutes) and p-value < 0.001.

CONCLUSIONS

CSB-KOH was more effective and faster than KOH in detecting fungal elements from corneal ulcers. Therefore, CSB-KOH may be beneficial in diagnosing fungal keratitis and preventing blindness. Moreover, to the best of our knowledge, this is the first use of CSB stain in fungal keratitis detection.

Evaluation of potassium monopersulfate footbath solution for controlling digital dermatitis in lactating dairy cattle. A randomized clinical trial

Our objective was to assess potassium monopersulfate as a disinfectant used in footbath to control digital dermatitis (DD) in dairy cows. We hypothesized that a potassium monopersulfate solution would control DD. A 180-day randomized negative controlled trial was conducted in a 265-Holstein free-stall facility. Throughout the trial, foot bathing was performed bi-weekly using a split (left vs. right feet) footbath: one tub filled with 1% potassium monopersulfate (treatment), the other with tap water (control). Digital dermatitis lesions were scored during trimming chute examinations of the unwashed hind heels every 90 days using the modified M-scoring system. Digital dermatitis lesions were re-categorized into four variables: 1) inactive; 2) active; 3) any; 4) inactive or absence of DD lesions. Three longitudinal outcomes were characterized: risks of 1) developing a DD lesion; 2) reactivating an inactive DD lesion; 3) development of an inactive or the absence of the DD lesion. A generalized linear model was used to compare the variables and longitudinal outcomes between treated and control groups. Prevalence of active DD lesions increased from 12.5% to 39.9% between days 0 and 90. This significant increase in prevalence justified the discontinuation of the study on day 90 for ethical reasons. There was no statistical difference between treated and control groups for the first outcome (RR: 1.0; 95% CI: 0.62, 1.7), the second outcome (RR: 1.0; 95% CI: 0.62,-1.7); or the third outcome (RR: 0.88; 95% CI: 0.37, 2.1). A 1% potassium monopersulfate footbath solution appears ineffective to control DD in this study.

Medical waste incineration fly ash-based magnesium potassium phosphate cement: Calcium-reinforced chlorine solidification/stabilization mechanism and optimized carbon reduction process strategy

The traditional solidification/stabilization (S/S) technology, Ordinary Portland Cement (OPC), has been widely criticized due to its poor resistance to chloride and significant carbon emissions. Herein, a S/S strategy based on magnesium potassium phosphate cement (MKPC) was developed for the medical waste incineration fly ash (MFA) disposal, which harmonized the chlorine stabilization rate and potential carbon emissions. The in-situ XRD results indicated that the Cl- was efficiently immobilized in the MKPC system with coexisting Ca2+ by the formation of stable Ca5(PO4)3Cl through direct precipitation or intermediate transformation (the Cl- immobilization rate was up to 77.29%). Additionally, the MFA-based MKPC also demonstrated a compressive strength of up to 39.6 MPa, along with an immobilization rate exceeding 90% for heavy metals. Notably, despite the deterioration of the aforementioned S/S performances with increasing MFA incorporation, the potential carbon emissions associated with the entire S/S process were significantly reduced. According to the Life Cycle Assessment, the potential carbon emissions decreased to 8.35 × 102 kg CO2-eq when the MFA reached the blending equilibrium point (17.68 wt.%), while the Cl- immobilization rate still remained above 65%, achieving an acceptable equilibrium. This work proposes a low-carbon preparation strategy for MKPC that realizes chlorine stabilization, which is instructive for the design of S/S materials.

Efficient Cr(VI) removal by pyrite/porous biochar: Critical role of potassium salt and sulphur

The excessive accumulation of hexavalent chromium (Cr(VI)) in the environment poses a risk to environment and human health. In the present study, a potassium bicarbonate-modified pyrite/porous biochar composite (PKBC) was prepared in a one-step process and applied for the efficient removal of Cr(VI) in wastewater. The results showed that PKBC can significantly remove Cr(VI) within 4 h over a wide range of pH (2-11). Meanwhile, the PKBC demonstrated remarkable resistance towards interference from complex ions. The addition of potassium bicarbonate increased the pore structure of the material and promoted the release of Fe2+. The reduction of Cr(VI) in aqueous solution was primarily attributed to the Fe(II)/Fe(III) redox cycle. The sulphur species achieved Fe(II)/Fe(III) cycle through electron transfer with iron, thus ensuring the continuous reduction capacity of PKBC. Besides, the removal rate was also maintained at more than 85% in the actual water samples treatment process. This work provides a new way to remove hexavalent chromium from wastewater and demonstrates the potential critical role of potassium bicarbonate and sulphur.

Determination of Related Substances in Promethazine Hydrochloride and Dextromethorphan Hydrobromide in Oral Solution by RP-HPLC Method

The goal of this study is to provide a single, widely applicable high-performance liquid chromatographic (HPLC) technique for the determination of related substances in multicomponent oral solution of promethazine hydrochloride and dextromethorphan hydrobromide. For the assessment of impurities of promethazine hydrochloride and dextromethorphan hydrobromide in oral solution, a unique, sensitive, quick, stability-indicating gradient HPLC technique has been created. For chromatographic separation, an Agilent Eclipse XDB-C18, 250 mm × 4.6 mm, 5 μm column was used with a buffered mobile phase consisting of a mixture of potassium dihydrogen phosphate pH 3.0:acetonitrile (80:20) v/v as mobile phase A and potassium dihydrogen phosphate pH 3.0:acetonitrile:methanol (10:10:80) v/v/v as mobile phase B. The separation was performed at a flow rate of 1.2 mL/min and a detection wavelength of 224 nm. The temperature of the column oven was regulated at 40°C. With good sensitivity and resolution, all compounds were effectively separated on a reverse-phase HPLC column. Acid, base, photolytic, thermal, oxidative and humidity stress conditions significantly degraded dextromethorphan hydrobromide and promethazine hydrochloride. The developed technique was validated according to the criteria of the International Conference on Harmonization for all validation parameters such as specificity, accuracy, linearity, precision, the limit of detection, the limit of quantitation and robustness.

Characterization of potassium-solubilizing fungi, Mortierella spp., isolated from a poplar plantation rhizosphere soil

Potassium-solubilizing microorganisms are capable of secreting acidic chemicals that dissolve and release potassium from soil minerals, thus facilitating potassium uptake by plants. In this study, three potassium-dissolving filamentous fungi were isolated from the rhizosphere soil of a poplar plantation in Jiangsu Province, China. Phylogenetic analyses based on ITS, 18 S, and 28 S showed that these three isolates were most similar to Mortierella. These strains also possessed spherical or ellipsoidal spores, produced sporangia at the hyphal tip, and formed petal-like colonies on PDA media resembling those of Mortierella species. These findings, along with further phenotypic observations, suggest that these isolates were Mortierella species. In addition, the potassium-dissolution experiment showed that strain 2K4 had a relatively high potassium-solubilizing capacity among these isolated fungi. By investigating the influences of different nutrient conditions (carbon source, nitrogen source, and inorganic salt) and initial pH values on the potassium-dissolving ability, the optimal potassium-solubilization conditions of the isolate were determined. When potassium feldspar powder was used as an insoluble potassium source, isolate 2K4 exhibited a significantly better polysaccharide aggregation ability on the formed mycelium-potassium feldspar complex. The composition and content of organic acids secreted by strain 2K4 were further detected, and the potassium-dissolution mechanism of the Mortierella species and its growth promotion effect were discussed, using maize as an example.

Extraction and separation of astaxanthin with the help of pre-treatment of Haematococcus pluvialis microalgae biomass using aqueous two-phase systems based on deep eutectic solvents

The microalgae Haematococcus pluvialis are the main source of the natural antioxidant astaxanthin. However, the effective extraction of astaxanthin from these microalgae remains a significant challenge due to the rigid, non-hydrolyzable cell walls. Energy savings and high-efficiency cell disruption are essential steps in the recovery of the antioxidant astaxanthin from the cysts of H. pluvialis. In the present study, H. pluvialis microalgae were first cultured in Bold's Basal medium under certain conditions to reach the maximum biomass concentration, and then light shock was applied for astaxanthin accumulation. The cells were initially green and oval, with two flagella. As the induction time increases, the motile cells lose their flagellum and become red cysts with thick cell walls. Pre-treatment of aqueous two-phase systems based on deep eutectic solvents was used to decompose the cell wall. These systems included dipotassium hydrogen phosphate salt, water, and two types of deep eutectic solvents (choline chloride-urea and choline chloride-glucose). The results of pre-treatment of Haematococcus cells by the studied systems showed that intact, healthy cysts were significantly ruptured, disrupted, and facilitated the release of cytoplasmic components, thus facilitating the subsequent separation of astaxanthin by liquid-liquid extraction. The system containing the deep eutectic solvent of choline chloride-urea was the most effective system for cell wall degradation, which resulted in the highest ability to extract astaxanthin. More than 99% of astaxanthin was extracted from Haematococcus under mild conditions (35% deep eutectic solvent, 30% dipotassium hydrogen phosphate at 50 °C, pH = 7.5, followed by liquid-liquid extraction at 25 °C). The present study shows that the pre-treatment of two-phase systems based on deep eutectic solvent and, thus, liquid-liquid extraction is an efficient and environmentally friendly process to improve astaxanthin from the microalgae H. pluvialis.

Examination of Oral Candida Infection in Primary Sjögren's Syndrome Patients

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by symptoms such as dry mouth, dry eyes, and other systematic symptoms. Due to the hyposalivation experienced by pSS patients, oral dysbacteriosis often occurs. A common complication of pSS is the oral Candida infection. In this article, the authors describe systematic methods that can effectively diagnose oral Candida infection and identify the Candida strains using saliva, oral mucosal swabs, or mouthwash from pSS patients. The Sabouraud's Dextrose Agar (SDA), hyphal formation assay, potassium hydroxide (KOH) smear test, and calcofluor white (CFW) staining assay are used for the diagnosis of oral Candida infection. A Candida diagnostic agar is used for the identification of Candida strains. Finally, antifungal susceptibility testing is used to determine appropriate antifungal drug treatment. This standardized method can enhance the diagnosis, treatment, and future research of pSS-related oral Candida infections. Early diagnosis, using this method, can also prevent any complications arising due to delay in receiving appropriate treatment.

Enhanced dewaterability of food waste digestate by biochar/potassium ferrate treatments: Performance and mechanisms

The combined process of biochar (BC) and potassium ferrate (PF) offers a fascinating technique for efficient dewatering of digestate. However, the effects of BC/PF treatment on the dewaterability and mechanisms of FWD are still unknown. This study aimed to reveal the impact mechanisms of BC/PF treatment on digestate dewatering performance. Experimental results indicated that BC/PF treatment significantly enhanced the dewaterability of digestate, with the minimum specific resistance to filtration of (1.05 ± 0.02) × 1015 m·kg-1 and water content of 57.52 ± 0.51% being obtained at the concentrations of 0.018 g·g-1 total solid (TS) BC300 and 0.20 g·g-1 TS PF, which were 8.60% and 13.59% lower than PF treatment, respectively. BC/PF treatment proficiently reduced the fractal dimension, bound water content, apparent viscosity, and gel-like network structure strength of digestate, as well as increased the floc size and zeta potential of digestate. BC/PF treatment promoted the conversion of extracellular polymeric substances (EPS) fractions from inner EPS to soluble EPS, increased the fluorescence intensity of the dissolved compounds, and enhanced the hydrophobicity of proteins. Mechanisms investigations showed that BC/PF enhanced dewatering through non-reactive oxygen species pathways, i.e., via strong oxidative intermediate irons species Fe(V)/Fe(IV). BC/PF treatment enhanced the solubilization of nutrients, the inactivation of fecal coliforms, and the mitigation of heavy metal toxicity. The results suggested that BC/PF treatment is an effective digestate dewatering technology which can provide technological supports to the closed-loop treatment of FWD.

High microplastic and anthropogenic particle contamination in the gastrointestinal tracts of tiger sharks (Galeocerdo cuvier) caught in the western North Atlantic Ocean

Few studies have documented microplastics (<5 mm) in shark gastrointestinal (GI) tracts. Here, we report microplastic contamination in the tiger shark (Galeocerdo cuvier), an apex predator and generalist feeder, at several different life stages. We examined seven stomachs and one spiral valve from eight individuals captured off the United States Atlantic and Gulf of Mexico coasts (eastern US) and conducted a literature review of publications reporting anthropogenic debris ingestion in elasmobranchs. Specimens were chemically digested in potassium hydroxide (KOH) and density separated using calcium chloride (CaCl2) before quantifying and categorizing suspected anthropogenic particles (>45 μm) by size, morphology, and colour. Anthropogenic particles were found in the stomachs and spiral valve of all sharks. A total of 3151 anthropogenic particles were observed across all stomachs with 1603 anthropogenic particles observed in a single specimen. A subset of suspected anthropogenic particles (14%) were chemically identified using Raman spectroscopy and μ-Fourier Transform Infrared spectroscopy to confirm anthropogenic origin. Overall, ≥95% of particles analyzed via spectroscopy were confirmed anthropogenic, with 45% confirmed as microplastics. Of the microplastics, polypropylene (32%) was the most common polymer. Diverse microparticle morphologies were found, with fragments (57%) and fibers (41%) most frequently observed. The high occurrence and abundance of anthropogenic particle contamination in tiger sharks is likely due to their generalist feeding strategy and high trophic position compared to other marine species. The literature review resulted in 32 studies published through 2022. Several methodologies were employed, and varying amounts of contamination were reported, but none reported contamination as high as detected in our study. Anthropogenic particle ingestion studies should continue in the tiger shark, in addition to other elasmobranch species, to further understand the effects of anthropogenic activities and associated pollution on these predators.

Enhancing drought, heat shock, and combined stress tolerance in Myrobalan 29C rootstocks with foliar application of potassium nitrate

BACKGROUND

Drought and heat stress are significant concerns to food security in arid and semi-arid regions, where global warming is predicted to increase both frequency and severity. To cope with these challenges, the use of drought-tolerant plants or technological interventions are essential. In this study, the effects of foliar potassium nitrate (KNO3) application on the stress tolerance and recovery of Myrobalan 29C rootstocks (Prunus cerasifera Ehrh.) were evaluated. These rootstocks are widely recognized for their adaptability and are extensively used in fruit production. To assess their response, the rootstocks were subjected to drought, heat shock, or a combination of both stressors. Additionally, they were treated with 1.0% KNO3 via foliar application. Throughout the stress and recovery periods, various morphological, physiological, and bio-chemical parameters were measured.

RESULTS

Based on our results, KNO3 treatment improved LRWC, Chl stability, SC, and key stress markers like proline, MDA, H2O2, along with antioxidant enzymes CAT, SOD, POD during both stress and recovery phases. Moreover, our results emphasized KNO3's critical role in hormone regulation under stress. KNO3 application significantly altered hormone levels, notably increasing ABA during drought and heat shock stress, essential for stress response and adaptation. In contrast, IAA, GA, and cytokinin's significantly increased during the recovery phase in KNO3-treated plants, indicating improved growth regulation and stress recovery. In addition, KNO3 application improved the recovery process of the rootstocks by restoring their physiological and biochemical functions.

CONCLUSION

This study suggests that the application of foliar KNO3 is an effective technique for enhancing the drought and heat tolerance as well as the recovery of Myrobalan 29C rootstocks. These results hold significant value for farmers, policymakers, and researchers, as they offer crucial insights into the development of drought-tolerant crops and the management of climate change's adverse effects on agriculture.

Synthesis and characterizations of conocarpus- and azadirachta-derived activated carbons as wastewater recycling material

Water being the most important fluid supporting the life as well as industry is getting sparse and polluted day by day. Activated carbon (AC) can be utilized in various applications of significant environmental impact and sustainable living such as carbon dioxide sensing and capturing, air purification, and water recycling. However, in the wake of the recent corona pandemic which resulted in global lockdown and took the entire world by shock, a cost-effective and simple synthesis of such a useful material remains dire need of time. Therefore, this paper describes a simple and cost-effective synthesis of activated carbon (AC) of high porosity and surface area derived from the pruning of conocarpus and azadirachta trees. In reference to the study under consideration, alongside numerous others, a furnace was employed to synthesize activated carbon. However, our approach utilized a more conventional methodology wherein the environmental parameters were not optimized. In furnace-based procedures, factors such as temperature, pressure, and humidity are meticulously regulated, contrasting with the conventional methodologies where such parameters lack optimal control. Consequently, employing a furnace does not constitute a cost-effective approach for the physical activation of organic samples thus proving a furnace is not imperative for physical activation. The synthesis was carried out by physical activation in the form of carbonization followed by chemical activation with potassium hydroxide (KOH). The influence of activated carbon from each pruning over filtration of water containing industrial dye was investigated. Activation temperature and impregnation ratio of 600-800 °C and 1:5 were selected respectively. X-ray diffraction patterns (XRD) for all AC samples indicted the appearance of broad peaks at 2θ value of 20-30° which confirms the presence of carbon in the sample. The physical morphology arrangement by SEM analysis showed uneven arrangement of pores of conocarpus which indicated higher iodine number and hence higher adsorption capacity of 442.13 mg/g.

Chemical Mineralization of AMD into Schwertmannite Fixing Iron and Sulfate Ions by Structure and Adsorption: Paving the Way for Enhanced Mineralization Capacity

Abundant iron and sulfate resources are present in acid mine drainage. The synthesis of schwertmannite from AMD rich in iron and sulfate could achieve the dual objectives of resource recovery and wastewater purification. However, schwertmannite cannot emerge spontaneously due to the Gibbs free energy greater than 0. This results in the iron and sulfate in AMD only being able to use the energy generated by oxidation in the coupling reaction to promote the formation of minerals, but this only achieved partial mineralization, which limited the remediation of AMD through mineralization. In order to clarify the mechanism of iron and sulfate removal by the formation of schwertmannite in AMD, kinetic and thermodynamic parameters were crucial. This work used H2O2 oxidation of Fe2+ as a coupling reaction to promote the formation of schwertmannite from 64.4% of iron and 15.7% of sulfate in AMD, and determined that 99.7% of the iron and 89.9% of sulfate were immobilized in the schwertmannite structural, and only a small fraction was immobilized by the adsorption of schwertmannite, both of which were consistent with second-order kinetics models. The thermodynamic data suggested that reducing the concentration of excess sulfate ions or increasing the energy of the system may allow more iron and sulfate to be immobilized by forming schwertmannite. Experimental verification using the reaction of potassium bicarbonate with the acidity in solution to increase the energy in the system showed that the addition of potassium bicarbonate effectively promoted the formation of schwertmannite from Fe3+ and SO42-. It provided a theoretical and research basis for the direct synthesis of schwertmannite from Fe3+ and SO42- rich AMD for the removal of contaminants from water and the recovery of valuable resources.

Preparation of Oily Sludge-Derived Activated Carbon and Its Adsorption Performance for Tetracycline Hydrochloride

Oily sludge-derived activated carbon was prepared using the potassium hydroxide (KOH) activation method using oily sludge as a raw material, and one-factor experiments determined the best conditions for preparing activated carbon. The activated carbon's morphological structure and surface chemical properties were analyzed by scanning different characterization tools, and the adsorption behavior of tetracycline hydrochloride was investigated. The results showed that the optimum conditions for preparing oily sludge-derived activated carbon were an activation temperature of 400 °C, activation time of 30 min, activator concentration of 1 mol/L, and impregnation ratio of 2 mL/g. After activation, the activated carbon had more pores and a more orderly crystal structure arrangement, the specific surface area was 2.07 times higher than that before activation, and the surface was rich in functional groups such as -HO, -C-O, -C=C, and -C-H, which increased the active sites of activated carbon. Physicochemical effects dominated the adsorption process. It belonged to the spontaneous heat absorption process under the quasi-secondary kinetic and Langmuir isothermal models. The maximum monolayer adsorption capacity of KOH-activated carbon was 205.1 mg·g-1.

Haemostatic discs demonstrate physical efficacy against microbes commonly associated with central-line-associated bloodstream infections

BACKGROUND

Vascular access devices form an essential component in the management of acute and chronic medical conditions. Introduction and ongoing management of these devices are linked with bundles of care aimed at reducing associated risks including bleeding and infection.

AIM

To evaluate the antimicrobial potential of the potassium ferrate haemostatic disc on Gram-positive (Staphylococcus aureus) and Gram-negative (Klebsiella pneumoniae, Pseudomonas aeruginosa) bacteria and on Candida albicans.

METHODS

The impact of the potassium ferrate disc was compared with the often-used chlorhexidine gluconate (CHG) impregnated disc to evaluate the potential efficacy of the potassium ferrate disc as an alternative to CHG in cases with an increased risk of active bleeding.

RESULTS

In the presence of anticoagulated blood, we observed an inhibitory effect of the haemostatic disc on microbial growth for microbial strains commonly associated with vascular access device related infections.

CONCLUSION

Our results indicate that the potassium ferrate disc may provide dual clinical benefits with both haemostatic and antimicrobial action observed during in-vitro testing.

Effect of dipotassium phosphate addition and heat on proteins and minerals in milk protein beverages

Our objective was to determine the effects of dipotassium phosphate (DKP) addition, heat treatments (no heat, high temperature, short time [HTST]: 72°C for 15 s, and direct steam injection UHT: 142°C for 2.3 s), and storage time on the soluble protein composition and mineral (P, Ca, K) concentration of the aqueous phase around casein micelles in 7.5% milk protein-based beverages made with liquid skim milk protein concentrate (MPC) and micellar casein concentrate (MCC). Milk protein concentrate was produced using a spiral wound polymeric membrane, and MCC was produced using a 0.1-µm ceramic membrane by filtration at 50°C. Two DKP concentrations were used (0% and 0.15% wt/wt) within each of the 3 heat treatments. All beverages had no other additives and ran through heat treatment without coagulation. Ultracentrifugation (2-h run at 4°C) supernatants of the beverages were collected at 1, 5, 8, 12, and 15-d storage at 4°C. Phosphorus, Ca, and K concentrations in the beverages and supernatants were measured using inductively coupled plasma spectrometry. Protein composition of supernatants was measured using Kjeldahl and sodium dodecyl sulfate-PAGE. Micellar casein concentrate and MPC beverages with 0.15% DKP had higher concentrations of supernatant protein, Ca, and P than beverages without DKP. Protein, Ca, and P concentrations were higher in MCC supernatant than in MPC supernatant when DKP was added, and these concentrations increased over storage time, especially when lower heat treatments (HTST or no heat treatment) had been applied. Dipotassium phosphate addition caused the dissociation of αS-, β-, and κ-casein, and casein proteolysis products out of the casein micelles, and DKP addition explained over 70% of the increase in supernatant protein, P, and Ca concentrations. Dipotassium phosphate could be removed from 7.5% of protein beverages made with fresh liquid MCC and MPC (containing a residual lactose concentration of 0.6% to 0.7% and the proportional amount of soluble milk minerals), as these beverages maintain heat-processing stability without DKP addition.

Study on the removal of fulvic acid in water by potassium ferrate-enhanced iron-manganese co-oxide film and its mechanism

The previous studies have shown that iron-manganese co-oxide film (MeOx) could simultaneously remove ammonium, manganese ion and bisphenol A. In this study, the removal of fulvic acid (FA) was explored by adding potassium ferrate (K2FeO4) to heighten the catalytic activity of MeOx. After adding about 3.0 mg/L potassium ferrate, the elimination efficiency of 7.0 mg/L FA by the MeOx increased from 20 to 50%. The effects of temperature and ammonium on the elimination of FA were investigated. Higher temperature (above 22 °C) and higher ammonium concentration (above 2.0 mg/L) caused a decrease in FA removal. Most of FA combined with the ferric hydroxide colloid produced by K2FeO4 in water to form macromolecular groups, and they were subsequently absorbed and covered on the surface of MeOx. Scanning electron microscope showed that more viscous flocs appeared on the surface of MeOx, and the film thickness became thicker. Electron energy-dispersive spectrometer analysis revealed a notable increased in the C-O element ratio and a significant decreased in the Mn-Fe element ratio on the surface of MeOx. From Fourier transform infrared spectroscopy, the content of transition metal carbonyl compounds increased in the surface of MeOx. XPS analysis confirmed that the presence of Fe3O4, FeO, Mn2O3 and Mn3O4 along with functional group substances of FA attached on the surface of MeOx. The removal mechanism of FA was studied.

Effect and its mechanism of potassium persulfate on aerobic composting process of vegetable wastes

Vegetable waste (VW) is a potential organic fertilizer resource. As an important way to utilize vegetable wastes, aerobic composting of VW generally has the problems of long fermentation cycle and incomplete decomposition of materials. In this study, 0.3-1.2% of potassium persulfate (KPS) was added to promote the maturity of compost. The results showed that the addition of KPS promoted the degradation of materials, accelerated the temperature rise of compost. KPS also promoted the formation of humic substances (HS). Compared with the control, HS contents of treatments with KPS addition increased by 7.81 ~ 17.52%. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) analysis reveal the mechanism of KPS affecting the composting process: KPS stimulated the degradation of various organic substances such as lignin at high temperature stage, and the degradation of lignin could accelerate the release and decomposition of other components; KPS made the structure of the material looser, with more voids and pores, and more specific surface area of the material, which was more suitable for microbial degradation activities. Therefore, the addition of KPS can promote the decomposition of organic matter in the early stage of composting, accelerate the process of thermophilic phase, and shorten the composting process and improve product maturity.

Synergistic leaching process for ion-exchange ammonium from weathered crust elution deposited rare earth tailings with potassium magnesium compound eluent

The ion-exchangeable ammonium (IE-A) that accounts for 60-90% of the total residual ammonium in rare earth tailings has great potential to pollute the surrounding environment, and much research has been done to seek an effective elution method. However, the current study mainly focused on the single salt solution, which made it hard to reach the desired elution efficiency. In this study, the efficient binary compound eluent was prepared, and the response surface experiments and dynamic elution were performed to optimize the elution condition and evaluate the practical application prospect. Batch experimental results showed that the best IE-A elution efficiency could be achieved at the K:Mg molar ratio of 8:2, the liquid-solid ratio of 26:1, and the concentration of 0.1 mol/L at the natural solution pH. Dynamic experimental results indicated that a higher concentration, flow rate, and elution temperature could all accelerate the elution process, and the highest elution efficiency could reach 99%. The fitting results by shrinking core models show that the apparent activation energy of IE-A was 4.24 kJ/mol in the temperature range of 288-328 K, and the reaction order was 0.16. XPS and FTIR revealed that IE-A was effectively eluted by a potassium and magnesium compound leaching agent via an ion-exchange reaction. Overall, the developed compound solution with potassium and magnesium is a candidate for an elution agent that could be used to remove residual ammonium in a closed field of rare earth ores.

Dermatophyte antigen kit: A useful diagnostic tool for onychomycosis

A dermatophyte antigen kit (DQT) was released in Japan as an in vitro diagnostic tool to identify tinea unguium in June 2022. From July 2022 to February 2023, we examined 75 potassium hydroxide (KOH)-negative patients (male, n = 23; female, n = 52; mean ± SD age, 63.6 ± 13.9 years) and determined the accuracy in confirming the fungal element with ZoomBlue™ staining at 400× magnification. The DQT results were classified into three categories. DQT-positive onychomycosis was detected in 27 patients with tinea unguium and two with non-dermatophyte onychomycosis. Fungal cultures were positive in 14 (51.8%) patients (Trichophyton rubrum [n = 11], T. interdigitale [n = 1], Fusarium solani [n = 1], and Talaromyces muroii [n = 1]). DQT-negative onychomycosis included ten patients with cured tinea unguium and 3 with Candida onychomycosis. Twenty-three patients had DQT-negative mimics for onychomycosis (onychauxis [n = 11], traumatic onycholysis [n = 8], yellow nail syndrome [n = 5], pincer nail deformity [n = 3], brittle nail syndrome [n = 2], contact dermatitis [n = 2], lichen planus [n = 1] and psoriasis [n = 1]). Because sparse, atrophic and/or fragmented mycelia are invisible in direct microscopy with potassium hydroxide (KOH) at 100× magnification, DQT was beneficial for diagnosing onychomycosis.

Contribution identification of hydrolyzed products of potassium ferrate on promoting short-chain fatty acids production from waste activated sludge

Potassium ferrate (K2FeO4) has been extensively employed to promote short-chain fatty acids (SCFAs) production from anaerobic fermentation of waste activated sludge (WAS) because of its potent oxidizing property and formation of alkaline hydrolyzed products (potassium hydroxide, KOH and ferric hydroxide, Fe(OH)3). However, whether K2FeO4 actually works as dual functions of both an oxidizing agent and an alkalinity enhancer during the anaerobic fermentation process remains uncertain. This study aims to identify the contributions of hydrolyzed products of K2FeO4 on SCFAs production. The results showed that K2FeO4 did not execute dual functions of oxidization and alkalinity in promoting SCFAs production. The accumulation of SCFAs using K2FeO4 treatment (183 mg COD/g volatile suspended solids, VSS) was less than that using either KOH (192 mg COD/g VSS) or KOH & Fe(OH)3 (210 mg COD/g VSS). The mechanism analysis indicated that the synergistic effects caused by oxidization and alkalinity properties of K2FeO4 did not happen on solubilization, hydrolysis, and acidogenesis stages, and the inhibition effect caused by K2FeO4 on methanogenesis stage at the initial phase was more severe than that of its hydrolyzed products. It was also noted that the inhibition effects of K2FeO4 and its hydrolyzed products on the methanogenesis stage could be relieved during a longer sludge retention time, and the final methane yields using KOH or KOH & Fe(OH)3 treatment were higher than that using K2FeO4, further confirming that dual functions of K2FeO4 were not obtained. Therefore, K2FeO4 may not be an alternative strategy for enhancing the production of SCFAs from WAS compared to its alkaline hydrolyzed products. Regarding the strong oxidization property of K2FeO4, more attention could be turned to the fates of refractory organics in the anaerobic fermentation of WAS.

Microscopic evidence of sandstone deterioration and damage by fungi isolated from the Angkor monuments in simulation experiments

The Angkor monuments have been registered on the World Cultural Heritage List of UNESCO, while the buildings built mostly of sandstone are suffering from serious deterioration and damage. Microorganisms are one of the leading causes for the sandstone deterioration. Identification of the mechanisms underlying the biodeterioration is of significance because it reveals the biochemical reaction involved so that effective conservation and restoration of cultural properties can be achieved. In this study, the fungal colonization and biodeterioration of sandstone in simulation experiments were examined using confocal reflection microscopy (CRM) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). Aspergillus sp. strain AW1 and Paecilomyces sp. strain BY8 isolated from the deteriorated sandstone of Angkor Wat and Bayon of Angkor Thom, respectively, were inoculated and incubated with the sandstone used for construction of Angkor Wat. With CRM, we could visualize that strain AW1 tightly attached to and broke in the sandstone with extension of the hyphae. Quantitative imaging analyses showed that the sandstone surface roughness increased and the cavities formed under the fungal hyphae deepened during the incubation of strains AW1 and BY8. These highlighted that the massive growth of fungi even under the culture conditions was associated with the cavity formation of the sandstone and its expansion. Furthermore, SEM-EDS indicated the flat and Si-rich materials, presumably quartz and feldspar, were found frequently at the intact sandstone surface. But the flatness was lost during the incubation, possibly due to the detachment of the Si-rich mineral particles by the fungal deterioration. Consequently, this study proposed a biodeterioration model of the sandstone in that the hyphae of fungi elongated on the surface of the sandstone to penetrate into the soft and porous sandstone matrix, damaging the matrix and gradually destabilize the hard and Si-rich minerals, such as quartz and feldspar, to the collapse and cavities.

Analysis of the Potassium-Solubilizing Priestia megaterium Strain NK851 and Its Potassium Feldspar-Binding Proteins

Potassium-solubilizing bacteria are an important microbial group that play a critical role in releasing mineral potassium from potassium-containing minerals, e.g., potassium feldspar. Their application may reduce eutrophication caused by overused potassium fertilizers and facilitate plants to utilize environmental potassium. In this study, a high-efficiency potassium-solubilizing bacterium, named NK851, was isolated from the Astragalus sinicus rhizosphere soil. This bacterium can grow in the medium with potassium feldspar as the sole potassium source, releasing 157 mg/L and 222 mg/L potassium after 3 days and 5 days of incubation, respectively. 16S rDNA sequencing and cluster analysis showed that this strain belongs to Priestia megaterium. Genome sequencing further revealed that this strain has a genome length of 5,305,142 bp, encoding 5473 genes. Among them, abundant genes are related to potassium decomposition and utilization, e.g., the genes involved in adherence to mineral potassium, potassium release, and intracellular trafficking. Moreover, the strong potassium-releasing capacity of NK851 is not attributed to the acidic pH but is attributed to the extracellular potassium feldspar-binding proteins, such as the elongation factor TU and the enolase that contains potassium feldspar-binding cavities. This study provides new information for exploration of the bacterium-mediated potassium solubilization mechanisms.

The Effect of Potassium Nitrate Supplementation on the Force and Properties of Extensor digitorum longus (EDL) Muscles in Mice

Adding potassium nitrate (KNO3) to the diet improves the physiological properties of mammalian muscles (rebuilds weakened muscle, improves structure and functionality). The aim of this study was to investigate the effect of KNO3 supplementation in a mouse model. BALB/c mice were fed a KNO3 diet for three weeks, followed by a normal diet without nitrates. After the feeding period, the Extensor digitorum longus (EDL) muscle was evaluated ex vivo for contraction force and fatigue. To evaluate the possible pathological changes, the histology of EDL tissues was performed in control and KNO3-fed groups after 21 days. The histological analysis showed an absence of negative effects in EDL muscles. We also analyzed 15 biochemical blood parameters. After 21 days of KNO3 supplementation, the EDL mass was, on average, 13% larger in the experimental group compared to the controls (p < 0.05). The muscle-specific force increased by 38% in comparison with the control group (p < 0.05). The results indicate that KNO3 has effects in an experimental mouse model, showing nitrate-diet-induced muscle strength. This study contributes to a better understanding of the molecular changes in muscles following nutritional intervention and may help develop strategies and products designated to treat muscle-related issues.

Continuous and simultaneous conversion of phosphogypsum waste to sodium sulfate and potassium sulfate using quaternary phase diagram

In this present work, the transformation of the Moroccan phosphogypsum (PG) waste, considered a potential source of sulfate, into potassium sulfate compound could help reduce environmental impact and create a new value chain for the phosphate industry. Generally, solid-liquid equilibria are frequently applied in chemical industries. They are a valuable aid in visualizing the precipitation, separation, and purification of a solid phase and the pathways by which crystallization can occur. This process aims to produce potassium sulfate (K₂SO₄), a high-value fertilizer, from sulfate solutions obtained after dissolving PG in a NaOH medium. The quaternary phase diagram Na⁺, K⁺//Cl^-, SO₄^2--H₂O at 25 °C was especially used to determine the operating conditions and the design of a crystallization process during the PG conversion into K₂SO₄. The Jänecke representation of this system enables the determination of the optimal trajectory in the phase diagram for the double decomposition reaction. X-ray fluorescent (XRF) and X-ray diffraction (XRD) techniques were conducted to identify the crystalline phases formed during our process. In summary, the results of this study could contribute to the development of a sustainable valorization PG. Furthermore, K₂SO₄ represents a good alternative to potassium chloride for chloride-sensitive crops.

Spatial distribution of fecal pollution indicators in sewage sludge flocs and their removal and inactivation as revealed by qPCR/viability-qPCR during potassium ferrate treatment

Sludge reuse and utilization is one of important routines of disseminating fecal pollution to surface water and groundwater. However, it remains unclear the spatial distribution of fecal pollution indicators in sludge flocs and their reductions during sludge treatment processes. In this study, the abundances of fecal pollution indicators including cross-assembly phage (crAssphage), JC and BK polyomavirus (JCPyV, BKPyV), human adenovirus (HAdV), the human-specific HF183 Bacteroides (HF183) and Escherichia coli (EC) in soluble extracellular polymeric substances (S-EPS), loosely-bound EPS (LB-EPS), tightly-bound EPS (TB-EPS), and pellets of sludge flocs were determined, and the effect of potassium ferrate (PF) treatment on their removal and inactivation was investigated by using both qPCR and viability-qPCR. Results showed that all investigated indicators were detected in each fraction of sludge flocs. The PF treatment led to a great migration of indicators from sludge pellets to sludge EPS and some extent of their inactivation in each fraction of sludge flocs. The overall reductions of human fecal indicators in sludge determined by qPCR were 0-1.30 logs, which were 0-2 orders of magnitude lower than those of 0.69-2.39 logs detected by viability-qPCR, implying their inactivation by PF treatment to potentially alleviate the associated human health risks.

Ultrahigh sorption of sulfamethoxazole by potassium hydroxide-modified biochars derived from bean-worm skin waste

Food processing of bean worm generates copious amount of skin as solid waste posing a serious environmental concern. The present study utilized bean worm skin (BWS) waste to produce KOH-modified biochars (KBWS-BCs) for the removal of sulfamethoxazole (SMX) from aqueous solution for the first time. Characterization of KBWS-BCs was systematically investigated via multiple instrumental analysis techniques. The sorption performance of KBWS-BCs as a function of solution pH, reaction time, initial SMX concentration, and reaction temperature was investigated using batch experiments. The classic kinetics and isotherm models were employed to fit the sorption data. KBWS-BCs exhibited large surface areas (3331-4742 m² g^-1) and ultrahigh sorption performance for SMX (maximum adsorption capacities of 909-2000 mg g^-1), which were comparable to those of other modified biochars and even those of well-designed materials. Thermodynamic study indicated that the sorption of SMX on KBWS-BCs was a spontaneous (△G° < 0) and exothermic (△H° < 0) process. Mechanism analysis showed that both chemisorption and physisorption were responsible for the adsorption of SMX by KBWS-BCs. Overall, recycling BWS for preparation of high-performance biochars can be a "win-win" strategy for both disposal of BWS and removal of SMX from wastewater.

Combined effects of hydrothermally-altered feldspar and water regime on cadmium minimization in rice

The accumulation of cadmium (Cd) in grains and edible parts of crops poses a risk to human health. Because rice is the staple food of more than half of the world population, reducing Cd uptake by rice is critical for food safety. HydroPotash (HYP), an innovative potassium fertilizer produced with a hydrothermal process, has the characteristics of immobilizing heavy metals and potential use for remediating Cd-contaminated soils. The objective of this study was to evaluate the HYP as a soil amendment to immobilize Cd in acidic soils and to reduce the accumulation of Cd in rice tissues. The experiment was performed in a greenhouse with a Cecil sandy loam soil (pH 5.3 and spiked with 3 mg Cd kg^-1) under either flooding conditions (water level at 4 cm above the soil surface) or at field capacity. Two hydrothermal materials (HYP-1 and HYP-2) were compared with K-feldspar + Ca(OH)₂ (the raw material used for producing HYP), Ca(OH)₂, zeolite, and a control (without amendment). After 30 days of soil incubation, HydroPotashs, the raw material, and Ca(OH)₂ increased both soil solution pH and electrical conductivity. These materials also decreased soluble Cd concentration (up to 99.7%) compared with the control (p < 0.05). After 145 days, regardless of the materials applied, plant growth was favored (up to 35.8%) under the flooded regime. HydroPotash-1 was more effective for increasing dry biomass compared with other amendments under both water regimes. HydroPotashs reduced extractable Cd in soil, Cd content in plant biomass at tillering and maturing stage, and were efficient in minimizing Cd accumulation in rice grains.

Improved Dewaterability of Waste Activated Sludge by Fe(II)-Activated Potassium Periodate Oxidation

Fe(II)-activated potassium periodate (KIO₄) oxidation was used to improve the dewaterability of waste-activated sludge for the first time. Compared with those of raw sludge, the capillary suction time (CST), specific resistance filtration (SRF), and water content of filter cake (W_C) of sludge treated using the Fe(II)/KIO₄ process under the optimal conditions (i.e., the initial pH = 6.8, KIO₄ dose = 1.4 mmol/g volatile suspended solids, Fe(II)/KIO₄ molar ratio = 1.2) decreased by 64.34%, 84.13%, and 6.69%, respectively. For conditioned sludge flocs, the Zeta potential and particle size were increased, and hydrophilic proteins in extracellular polymeric substances (EPS) were partly degraded, accompanied by the transformation of tightly bound EPS into soluble EPS and the conversion of dense sludge flocs into loose and porous ones. During Fe(II)/KIO₄ oxidation, Fe(IV) and the accompanying ^•OH were determined as the predominant reactive species and the underlying mechanism of sludge EPS degradation was proposed. This work provides a prospective method for conditioning the sludge dewaterability.

Preparation of magnesium potassium phosphate cement using by-product MgO from Qarhan Salt Lake for low-carbon and sustainable cement production

Herein, to reduce CO₂ emissions and energy consumption and to promote the recycling of waste resources, two types of boron-containing MgO by-products, which were obtained by lithium extraction from Qarhan Salt Lake, China, were used as substitutes for dead-burned MgO to prepare magnesium phosphate potassium cement (MKPC) as a rapid repair material. First, the phase composition and particle-size distribution of the MgO by-product were investigated. The effects of different MgO sources, molar ratio of MgO to KH₂PO₄ (M/P), and curing age on the setting time and mechanical properties of MKPC were then studied. Based on the results, the mix proportion of MKPC was optimized. Finally, X-ray diffractometry, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), differential thermogravimetric (DTG) analysis, and mercury intrusion porosimetry were used to characterize the phase and microstructure evolution of MKPC prepared with different MgO contents. The results demonstrated that the by-product MgO prolonged the setting time of MKPC to more than 40 min. In addition, in the initial stage of hydration, the compressive strength of the MgO by-product was slightly lower than that of the dead-burned MgO; however, with increasing age, the mechanical properties of MKPC prepared by by-product MgO were excellent (up to 60 MPa). The phase and microstructure results revealed that the main hydration product of MKPC prepared using the three types of MgO was MgKPO₄·6H₂O. Combined with the physical and chemical properties of the raw materials, it was confirmed that the larger particle size and the coexisting impurities from the salt lake were the main reasons for the longer setting time of the MKPC prepared by the by-product MgO. We believe that this research will be of great significance for the preparation of low-carbon, low-cost, and high-performance MKPC materials.

Exploring the role of potassium ferrate and straw fiber in enhancing the strength of cement-based solidified municipal sludge

The effect of potassium ferrate (PF) and straw fiber (SF) on the strength of cement-based solidified municipal sludge, including the influence of reducing the organic matter in the sludge on the efficiency of the hydration of the cement, was studied. Single-factor tests, orthogonal tests, and linear weighted optimization methods were used to obtain suitable ratios to meet practical requirements, and then SEM and XRD analyses were used to explore the solidification mechanism. The results showed that PF and SF had significant influence on the strength, with SF having the greatest influence and the strength increasing with the amount of both admixtures, and cement had no significant influence on the strength. After linear weighting optimization, the ideal dosage was found to be 20% cement, 20% PF, and 5% SF, which produced a solidified sludge that had an strength of 126.87 kPa, far higher than the 50 kPa required to qualify for disposal in landfills. Analysis of the mineral content and microstructure showed that PF and SF could promote cement hydration and produce more hydration products, and the density of the optimized sample was much higher than that of the raw sludge and a sludge sample mixed with 20% cement alone.

Effects of potassium persulfate on nitrogen loss and microbial community during cow manure and corn straw composting

Strong oxidants can reduce the emission of NH₃ during composting. But as a commonly used oxidant, the influence of persulfate on nitrogen transformation during composting is unclear. In this study, the effects of 0.3 %-1.2 % potassium persulfate (PS) on nitrogen losses and microbial community during air-dried cow manure composting were investigated. The results showed that PS could reduce nitrogen losses compared to the control. This was because it decreased pH and the maximum NH₄⁺-N content of treatments, which was beneficial to nitrogen retention. In addition, Pseudoxanthomonas and Chelativorans were enriched compared to the control, which might be associated with NH₄⁺-N transformation and nitrogen fixation. Meanwhile, PS increased the abundance of thermophilic lignocellulose degrading bacteria, and 0.3 % and 0.6 % PS increased the maximum temperature and the duration of the thermophilic period. This study indicated that PS could reduce nitrogen losses in composting and greatly influence nitrogen transforming and lignocellulose degrading bacteria.

Mechanistic understanding of Curium(III) sorption on natural K-feldspar surfaces

To assess a reliable safety case for future deep underground repositories for highly active nuclear waste the retention of radionuclides by the surrounding host rock must be understood comprehensively. Retention is influenced by several parameters such as mineral heterogeneity and surface roughness, as well as pore water chemistry (e.g., pH). However, the interplay between those parameters is not yet well understood. Therefore, we present a correlative spectromicroscopic approach to investigate sorption of the actinide Cm(III) on: 1) bulk K-feldspar crystals to determine the effect of surface roughness and pH (5.5 and 6.9) and 2) a large feldspar grain as part of a complex crystalline rock system to observe how sorption is influenced by the surrounding heterogeneous mineralogy. Our findings show that rougher K-feldspar surfaces exhibit increased Cm(III) uptake and stronger complexation. Similarly, increasing pH leads to higher surface loading and stronger Cm(III) binding to the surface. Within a heterogeneous mineralogical system sorption is further affected by neighboring mineral dissolution and competitive sorption between mineral phases such as mica and feldspar. The obtained results express a need for investigating relevant processes on multiple scales of dimension and complexity to better understand trivalent radionuclide retention by a potential repository host rock.

Potassium ferrate pretreatment promotes short chain fatty acids yield and antibiotics reduction in acidogenic fermentation of sewage sludge

During the acidogenic fermentation converting waste activated sludge (WAS) into short-chain fatty acids (SCFA), hydrolysis of complex organic polymers is a limiting step and the transformation of harmful substances (such as antibiotics) during acidogenic fermentation is unknown. In this study, potassium ferrate (K₂FeO₄) oxidation was used as a pretreatment strategy for WAS acidogenic fermentation to increase the hydrolysis of sludge and destruct the harmful antibiotics. Pretreatment with K₂FeO₄ can effectively increase the SCFA production during acidogenic fermentation and change the distribution of SCFA components. With the dosage of 0.2 g/g TS, the maximum SCFA yield was 4823 mg COD/L, which is 28.3 times that of the control group; acetic acid accounts for more than 90% of the total SCFA. The higher dosage (0.5 g/g TS) can further increase the proportion of acetic acid, but inhibit the overall performance of SCFA production. Apart from the promotion of hydrolysis and acidogenesis, K₂FeO₄ pretreatment can also simultaneously oxidizes and degrades part of the antibiotics in the sludge. When the dosage is 0.5 g/g TS, the degradation efficacy of antibiotics is the most significant, and the contents of ofloxacin, azithromycin, and tetracycline in the sludge are reduced by 69%, 42%, and 50%, respectively. In addition, K₂FeO₄ pretreatment can also promote the release of antibiotics from sludge flocs, which is conducive to the simultaneous degradation of antibiotics in the subsequent biological treatment process.

pH regulated potassium ferrate oxidation promotes acetic acid yield and phosphorous recovery rate from waste activated sludge

To improve the dose efficiency of K₂FeO₄ in waste activated sludge (WAS) treatment, pH regulation on K₂FeO₄ pretreatment and acidogenic fermentation was investigated. Four pretreatments were compared, i.e. pH3 + 50 g/kg-TS, pH10 + 50 g/kg-TS, neutral pH + 50 g/kg-TS and neutral pH + 100 g/kg-TS (without pH adjustment). The higher short chain fatty acids (SCFAs) yield and phosphorous dissolution rate was found under the condition of pH 10.0. In pH10 + 50 g/kg-TS, the maximum concentration of SCFAs was 5591 mg-COD/L, which yield was 22.6 times higher than that of the neutral pH + 50 g/kg-TS (237 mg COD/L). The acidogenic fermentation period could be shortened to 5 days and acetic acid accounted for 70 % of SCFAs. Furthermore, PO₄^3--P in the hydrolysate (346.5 mg/L) accounted for 47.59 % of TP, which is easier to be recovered by chemical precipitation. Therefore, a more economical and feasible utilization mode of potassium ferrate was proposed.

Potassium perchlorate effects on primordial germ cells of developing medaka larvae

Perchlorate is a chemical compound commonly used in military artillery and equipment. It has been detected in drinking water, air, soil, and breast milk. Exposure of humans to perchlorate can occur in the theater of war and areas adjacent to military training grounds. A high concentration of perchlorate has been found to affect reproduction in vertebrates, including fish. However, whether environmental concentrations of perchlorate can affect primordial germ cells (PGCs), the founders of sperm and eggs, is not clearly understood. In the present study, we examined the effects of 0, 10, 100, and 1000 μg/L potassium perchlorate exposure on the embryonic development of medaka and their PGCs. Perchlorate exposure delayed hatching time, reduced heartbeat, inhibited migration of PGCs, and increased developmental deformities in the larvae. The 10 and 20 mg/L concentrations of perchlorate were lethal to embryos, whereas vitamin C co-treatment (1 mg/L) completely blocked perchlorate-induced mortality. RNA-seq analysis of isolated PGCs showed a non-linear pattern in expression profiles of differentially altered genes. Significantly upregulated genes were found in PGCs from the 10 and 1000 μg/L groups, whereas the 100 μg/L groups showed the highest number of significantly downregulated genes. Gene ontology analysis predicted differentially expressed genes to be involved in proteolysis, metabolic processes, peptides activity, hydrolase activity, and hormone activity. Among the cellular components, extracellular, intracellular, sarcoplasmic, and 6-phosphofructokinase and membrane-bounded processes were affected. Ingenuity Pathway Analysis of PGC transcriptomes revealed thyroid hormone signaling to be affected by all concentrations of perchlorate. The present results suggested that perchlorate affected the development of medaka larvae and vitamin C was able to ameliorate perchlorate-induced embryo mortality. Additionally, perchlorate altered the global transcriptional network in PGCs in a non-linear fashion suggesting its potential effects on developing germ cells and fertility.

Aerial and Collimated Sensor Radiological Mapping Following Dispersal of Activated Potassium Bromide

The exposure rate distribution was quantified over a site of three activated potassium bromide radiological dispersal device detonations at the Idaho National Laboratory Radiological Response Training Range with unmanned aerial vehicle (UAV) and ground-based methods. Discussions on the methods' survey characteristics, such as survey time, data spatial resolution, and area coverage, serve to inform those concerned with radiological response and cleanup efforts. Raster scans over the site at 4 m s-1 with 6 m between passes at an altitude of 4 m above ground level were executed with a 2.54 cm × 2.54 cm × 7.62 cm cesium iodide, sodium-doped [CsI(Na)] sensor mounted to a UAV. Exposure rates were calculated from the spectra obtained by the CsI(Na) using a flux unfolding method. Data obtained from the UAV raster were interpolated to produce a continuous exposure rate map across the site. The activity on the ground, inferred from collimated, ground-based sensor (Nomad) measurements in previous work, was used to calculate exposure rate distributions at the same altitude as the UAV-mounted CsI(Na) sensor. Agreement between Nomad and UAV exposure rate distributions is observed at rates up to 1.0 mR h-1 after corrections for ground effects were implemented on the Nomad data. Discrepancies in exposure rate contours are present at higher rates, directly above the detonation locations. In areas of high exposure rate gradients, it is anticipated that a faster UAV-mounted sensor and more refined scans by the UAV will improve characterization of the distribution.

Role of the sedimentary organic matter structure and microporosity on the degradation of nonylphenol by potassium ferrate

In this study, the role of organic matter structure and microporosity in the adsorption and degradation of radioactive nonylphenol in sediments treated with potassium ferrate solutions was investigated. The demineralized fractions and acid non-hydrolyzable fractions were isolated and characterized via advanced solid-state ¹³C nuclear magnetic resonance and CO₂ gas adsorption technology, respectively. Radioactive nonylphenol in the sediments was also fractionated into ¹⁴CO₂, water-soluble residues, extractable residues, and strongly bound residues after treatment with potassium ferrate. A first-order, two-compartment kinetic model well described the mineralization and degradation kinetics of radioactive nonylphenol in the sediment (R² > 0.99). The degradation percentages of spiked nonylphenol were highly negatively correlated with aromatic carbon, aliphatic carbon, and microporosity estimated from acid-non-hydrolyzable fractions in the bulk sediments (R² > 0.82, p < 0.01). The percentages of adsorbed parent nonylphenol residues were highly positively correlated with aromatic carbon, aliphatic carbon, and microporosity estimated from acid-non-hydrolyzable fractions in the bulk sediments (R² > 0.90, p < 0.01). The parent nonylphenol compound desorbed into the aqueous phase and was completely degraded. This study is the first to demonstrate the important role of aromatic carbon, aliphatic carbon, and microporosity in acid non-hydrolyzable fractions on the degradation of nonylphenol during the potassium ferrate oxidation treatment process.

A Role for Allantoate Amidohydrolase (AtAAH) in the Germination of Arabidopsis thaliana Seeds

Seed dormancy is a very complex trait controlled by interactions between genetic and environmental factors. Nitrate is inversely correlated with seed dormancy in Arabidopsis. This is explained by the fact that seed dry storage (after-ripening) reduces the need for nitrogen for germination. When nitrate is absorbed by plants, it is first reduced to nitrite and then to ammonium for incorporation into amino acids, nucleic acids and chlorophyll. Previously, we showed that ALLANTOATE AMIDOHYDROLASE (AtAAH) transcripts are up-regulated in imbibed dormant seeds compared with after-ripened seeds. AAH is an enzyme in the uric acid catabolic pathway which catalyzes the hydrolysis of allantoate to yield CO2, NH3 and S-ureidoglycine. This pathway is the final stage of purine catabolism, and functions in plants and some bacteria to provide nitrogen, particularly when other nitrogen sources are depleted. Ataah mutant seeds are more dormant and accumulate high levels of allantoate, allantoin and urea, whereas energy-related metabolites and several amino acids are lower upon seed imbibition in comparison with Columbia-0. AtAAH expression could be detected during the early stages of seed development, with a transient increase around 8 d after pollination. AtAAH expression is the highest in mature pollen. The application of exogenous potassium nitrate can partly complement the higher dormancy phenotype of the Ataah mutant seeds, whereas other nitrogen sources cannot. Our results indicate that potassium nitrate does not specifically overcome the alleviated dormancy levels in Ataah mutant seeds, but promotes germination in general. Possible pathways by which AtAAH affects seed germination are discussed.

Membrane based reactors for sustainable treatment of Coronopus didymus L. by developing Iodine doped potassium oxide Catalyst under Dynamic conditions

Green nano-technology together with the availability of eco-friendly and alternative sources are the promising candidates to combat environment deteriorations and energy clutches globally. The current work focuses on the synthesis and application of newly synthesized nano catalyst of Iodine doped Potassium oxide I (K₂O) for producing sustainable biodiesel from novel non-edible seed oils of Coronopus didymus L. using membrane based contactor to avoid emulsification and phase separation issues. Highest biodiesel yield (97.03%) was obtained under optimum conditions of 12:1 methanol to oil ratio, reaction temperature of 65 °C for 150 min with the 1.0 wt% catalyst concentration. The lately synthesized, environment friendly and recyclable Iodine doped Potassium oxide K (IO)₂ catalyst was synthesized via chemical method followed by characterization via advanced techniques including EDX, XRD, FTIR and SEM analysis. The catalyst was proved to be stable and efficient with the reusability of five times in transesterification reaction. These analysis have reported the sustainability, stability and good quality of biodiesel from seed oil of Coronopus didymus L. using efficient Iodine doped potassium oxide catalyst. Thus, non-edible, environment friendly and novel Coronopus didymus L. seeds and their extracted oil along with Iodine doped potassium oxide catalyst seems to be highly affective, sustainable and better alternative source to the future biodiesel industry. Also, by altering the reaction equilibrium and lowering the purification phases of the process, these studies show the potential of coupling transesterification and a membrane contactor.

Adsorption of brilliant green dye onto activated carbon prepared from cashew nut shell by KOH activation: Studies on equilibrium isotherm

Activated carbon from cashew nut shell via a potassium hydroxide (KOH) at 600 °C in an N₂ atmosphere and their characteristics using FT-IR, XRD, SEM with EDS, and BET analysis was investigated. The cashew nut shell activated carbon obtained by KOH activation with a CNS/KOH ratio of 1:1 at 600 °C (N₂ atmosphere) for 2 h had the highest surface area (407.80 m²/g) as compared to other ratio samples. Amongst, CNS/KOH ratios of 1:1 sample are used for the adsorbent, they are effects of contact time, pH, adsorbent dose, and initial dye concentration on brilliant green (BG) removal efficiency were studied. Moreover, the Langmuir and Freundlich adsorption models consisted utilized to affirm the adsorption isotherms. They are, best fitting for BG experimental equilibrium data was achieved with the Langmuir isotherm, giving a maximum BG adsorption capacity of 243.90 mg/g.

Ball milling potassium ferrate activated biochar for efficient chromium and tetracycline decontamination: Insights into activation and adsorption mechanisms

Herein, novel Fe-biochar composites (MBC_BM500 and MBC_BM700) were synthesized through K₂FeO₄ co-pyrolysis and ball milling, and were used to eliminate Cr(VI)/TC from water. Characterization results revealed that higher temperature promoted formation of zero-valent iron and Fe₃C on MBC_BM700 through carbothermal reduction between K₂FeO₄ and biochar. The higher specific surface area and smaller particle size of MBC_BM500/700 stemmed from the corrosive functions of K and the ball milling process. And the maximal uptake amount of MBC_BM700 for Cr(VI)/TC was 117.49/90.31 mg/g, relatively higher than that of MBC_BM500 (93.86/84.15 mg/g). Furthermore, ion exchange, pore filling, precipitation, complexation, reduction and electrostatic attraction were proved to facilitate the adsorption of Cr(VI), while hydrogen bonding force, pore filling, complexation and π-π stacking were the primary pathways to eliminate TC. This study provide a reasonable design of Fe-carbon materials for Cr(VI)/TC contained water remediation, which required neither extra modifiers nor complex preparation process.

Nanoporous Carbon from Oil Palm Leaves via Hydrothermal Carbonization-Combined KOH Activation for Paraquat Removal

In this study, nano-porous carbon was completely obtained from oil palm leaves (OPL) by hydrothermal pretreatment with chemical activation, using potassium hydroxide (KOH) as an activating agent. Potassium hydroxide was varied, with different ratios of 1:0.25, 1:1, and 1:4 (C: KOH; w/w) during activation. The physical morphology of nano-porous carbon has a spongy, sponge-like structure indicating an increase in specific surface area and porosity with the increasing amount of KOH activating agent. The highest specific surface area of OPL nano-porous carbon is approximately 1685 m²·g^-1, with a total pore volume of 0.907 cm³·g^-1. Moreover, the OPL nano-porous carbon significantly showed a mesoporous structure designed specifically to remove water pollutants. The adsorptive behavior of OPL nano-porous carbon was quantified by using paraquat as the target pollutant. The equilibrium analyzes were explained by the Langmuir model isotherm and pseudo-second-order kinetics. The maximum efficiency of paraquat removal in wastewater was 79%, at a paraquat concentration of 400 mg·L^-1, for 10 min in the adsorption experiment. The results of this work demonstrated the practical application of nano-porous carbon derived from oil palm leaves as an alternative adsorbent for removing paraquat and other organic matter in wastewater.