Understanding microplastic presence in different wastewater treatment processes: Removal efficiency and source identification

Municipal effluents discharged from wastewater treatment plants (WWTPs) are a considerable source of microplastics in the environment. The dynamic profiles of microplastics in treatment units in WWTPs with different treatment processes remain unclear. This study quantitatively analyzed microplastics in wastewater samples collected from different treatment units in two tertiary treatment plants with distinct processes. The influents contained an average of 15.5 ± 3.5 particles/L and 38.5 ± 2.5 particles/L in the two WWTPs with in the oxidation ditch process and the integrated fixed-film activated sludge process, respectively. Interestingly, microplastic concentrations in the influent were more influenced by the population density in the served area than sewage volume or served population equivalent. Throughout the treatment process, concentrations were reduced to 1.5 ± 0.5 particles/L and 1.0 ± 1.0 particles/L in the final effluents, representing an overall decrease of 90% and 97%, in WWTPs with the oxidation ditch process and integrated fixed-film activated sludge process, respectively. A significant proportion of the microplastics were removed during the primary treatment stage in both WWTPs, with better performance for foam, film, line-shaped and large-sized microplastics. Most microplastics were accumulated in activated sludge, indicating its key role as the primary sink in WWTPs. The multiple correspondence analysis identified laundry washing and daily necessities such as packaging and containers as the major contributors to microplastics in WWTPs. The study proposed recommendations for upgrading WWTPs, modifying designs, and implementing strategies to reduce microplastic sources, aiming to minimize the release of microplastics into the environment. These findings can shed lights on the sources of microplastics in WWTPs, and advance our understanding of the mechanisms for more effective microplastic removals in wastewater treatment technologies in future applications.

More resilient polyester membranes for high-performance reverse osmosis desalination

Thin-film composite reverse osmosis membranes have remained the gold standard technology for desalination and water purification for nearly half a century. Polyamide films offer excellent water permeability and salt rejection but also suffer from poor chlorine resistance, high fouling propensity, and low boron rejection. We addressed these issues by molecularly designing a polyester thin-film composite reverse osmosis membrane using co-solvent-assisted interfacial polymerization to react 3,5-dihydroxy-4-methylbenzoic acid with trimesoyl chloride. This polyester membrane exhibits substantial water permeability, high rejection for sodium chloride and boron, and complete resistance toward chlorine. The ultrasmooth, low-energy surface of the membrane also prevents fouling and mineral scaling compared with polyamide membranes. These membranes could increasingly challenge polyamide membranes by further optimizing water-salt selectivity, offering a path to considerably reducing pretreatment steps in desalination.

Modulating electron density enable efficient cascade conversion from peroxymonosulfate to superoxide radical driven by electron-rich/poor dual sites

The superoxide radical (•O2-)-mediated peroxymonosulfate (PMS)-based photo-Fenton-like reaction enables highly selective water decontamination. Nevertheless, the targeted construction of •O2--mediated photo-Fenton-like system has been challenging. Herein, we developed an electron-rich/-poor dual sites driven •O2--mediated cascade photo-Fenton-like system by modulating electron density. Experimental and theoretical results demonstrated that PMS was preferentially adsorbed on electron-poor Co site. This adsorption promoted O-O bond cleavage of PMS to generate hydrogen peroxide (H2O2), which then migrated to electron-rich O site to extract eg electrons for O-H bond cleavage, rather than competing with PMS for Co site. The developed versatile cascade reaction system could selectively eliminate contaminants with low n-octanol/water partition constants (KOW) and dissociation constants (pKa) and remarkably resist inorganics (Cl-, H2PO4- and NO3-), humic acid (HA) and even real water matrices (tap water and secondary effluent). This finding provided a novel and plausible strategy to accurately and efficiently generate •O2- for the selective water decontamination.

Efficient separation of impurities Fe/Al/Ca and recovery of Zn from electroplating sludge using glucose as reductant

Electroplating sludge (ES), a hazardous waste containing heavy metals and Fe/Al/Ca impurities, is conventionally disposed of in landfills. In this study, a pilot-scale vessel with an effective capacity of 20 L was applied to recycle Zn from real ES. The sludge contained 6.3 wt% Fe, 6.9 wt% Al, 2.6 wt% Si, 6.1 wt% Ca, and 17.6 wt% Zn and was treated using a four-step method. First, ES was dissolved in nitric acid after washing in a water bath at 75 °C for 3 h to produce an acidic solution with Fe, Al, Ca, and Zn concentrations of 4527.2, 3116.1, 3357.7, and 21,275 mg/L, respectively. Second, the acidic solution was added with glucose at an Mglucose/Mnitrate ratio of 0.08 and hydrothermally treated at 160 °C for 4 h. During this step, nearly 100 % Fe and 100 % Al were simultaneously removed as a mixture containing 53.1 wt% Fe2O3 and 45.7 wt% Al2O3. This process was repeated five times, during which the Fe/Al removal and Ca/Zn loss rates remained unchanged. Third, the residual solution was adjusted with sulfuric acid, and over 99 % Ca was removed as gypsum. The residual Fe, Al, Ca, and Zn concentrations were 0.44, 0.88, 52.59, and 31,177.1 mg/L, respectively. Finally, Zn in the solution was precipitated as ZnO with a concentration of 94.3 %. Economic calculations showed that each 1 t of ES processed created revenue of about $122. This is the first study of high-value metal resource recovery using real electroplating sludge at the pilot scale. This work highlights the pilot-scale application of resource utilization of real ES and provides new insights into the recycling of heavy metals from hazardous waste.

Aquifer clogging caused by chlorine disinfection during the reclaimed water recharge

Aquifer clogging plays a critical role in the efficiency of reclaimed water recharge. While chlorine disinfection is commonly used for reclaimed water, its impact on clogging has seldom been discussed. Thus, this study aimed to investigate the mechanism of chlorine disinfection on clogging by establishing a lab-scale reclaimed water recharge system that utilized chlorine-treated secondary effluent as feed water. The findings indicated that increasing the chlorine concentration led to a surge in the total amount of suspended particles, and the median particle size increased from 2.65 μm to 10.58 μm. Furthermore, the fluorescence intensity of dissolved organic matter decreased by 20%, with 80% of these compounds, including humic acid, becoming entrapped within the porous media. Additionally, the formation of biofilms was also found to be promoted. Microbial community structure analysis unveiled a consistent dominance of Proteobacteria consistently exceeded 50% in relative abundance. Moreover, the relative abundance of Firmicutes increased from 0.19% to 26.28%, thereby verifying their strong tolerance to chlorine disinfection. These results showed that higher chlorine concentrations could stimulate microorganisms to secrete an increased quantity of extracellular polymeric substance (EPS) and form a coexistence system with the trapped particles and natural organic matter (NOM) within the porous media. Consequently, this supported the formation of biofilms, thereby potentially elevating the risk of aquifer clogging.

Enhanced degradation of emerging contaminants by percarbonate/Fe(II)-ZVI process: case study with nizatidine

Pharmaceuticals have recently emerged as a significant environmental concern due to the growth of population, expansion of industry, and the shift in modern lifestyles. Herein, we present a Fe(II)/percarbonate (SPC) process with dramatically enhanced efficiency by the introduction of zerovalent iron (ZVI). After the addition of ZVI, the removal rate of nizatidine (NZTD) went up from 71.7 to 84.2%. The removal rate of NZTD decreases with rising pH and speeds up with increasing temperature. It was found that under the condition of pH = 7 and T = 25 °C, the molar ratio of the optimal concentration of NZTD degradation in the system was [NZTD]₀:[SPC]₀:[Fe(II)]₀:[ZVI]₀ = 1:8:24:16, with a degradation rate of 99.8%. At the same time, target pollutants can also be successfully eliminated from actual water bodies. Moreover, we test for toxicity using luminescent bacteria, and the results demonstrate that the system is capable of effectively decreasing the toxicity of NZTD. The research findings can contribute to the clarification of the migration and transformation law of NZTD in the oxidation process, thereby providing a scientific basis and technical support for the removal of NZTD in the tertiary water treatment for a water source.

Progress in Research and Application of Metal-Organic Gels: A Review

In recent years, metal-organic gels (MOGs) have attracted much attention due to their hierarchical porous structure, large specific surface area, and good surface modifiability. Compared with MOFs, the synthesis conditions of MOGs are gentler and more stable. At present, MOGs are widely used in the fields of catalysis, adsorption, energy storage, electrochromic devices, sensing, analysis, and detection. In this paper, literature metrology and knowledge graph visualization analysis are adopted to analyze and summarize the literature data in the field of MOGs. The visualization maps of the temporal distribution, spatial distribution, authors and institutions' distribution, influence of highly cited literature and journals, keyword clustering, and research trends are helpful to clearly grasp the content and development trend of MOG materials research, point out the future research direction for scholars, and promote the practical application of MOGs. At the same time, the paper reviews the research and application progress of MOGs in recent years by combining keyword clustering, time lines, and emergence maps, and looks forward to their challenges, future development trend, and application prospects.

A modelling approach to explore the optimum bubble size for micro-nanobubble aeration

Bubble aeration has been widely applied in water/wastewater treatment, however its low gas utilization rate results in high energy consumption. Application of micro-nanobubbles (MNB) has emerged as a process with the potential to significantly increase gas utilisation due to their high relative surface area and high gas-liquid mass transfer efficiency. In this study, we demonstrate through calibrated models that MNB of an optimum bubble size can shrink and burst at or below the water surface enabling (1) all encapsulated gas to thoroughly dissolve in water, and (2) the bursting of nanobubbles to potentially generate free radicals. Through the understanding of MNB dimensional characteristics and bubble behaviour in water, a dynamic model that integrated force balance (i.e. buoyancy force, gravity, drag force, Basset force and virtual mass force), and mass transfer was developed to describe the rising velocity and radius variation of MNB along its upward trajectory. Unlike for conventional millimetre-sized bubbles, intensive gas dissolution of MNBs led to radius reduction for small bubbles, while a large initial radius triggers bubble swelling. The initial water depth was also crucial, where greater depth could drive the potential for bubble shrinkage so that they were more liable to contract. For example, the optimum bubble size of air (42-194 μm) and oxygen (127-470 μm) MNB that could achieve complete gas transfer (100% gas utilisation) for a range of specific water depths (0.5-10 m) were calculated. The modelling results for microbubbles (10-530 μm) were well validated by the experimental data (R²>0.85). However, the validation of the modelling results for nanobubble (<1 μm) aeration requires further study due to a lack of available empirical data. In this study, the proposed model and analysis provided new insights into understanding bubble dynamics in water and offered fundamental guidance for practitioners looking to upgrade bubble aeration system.

Synergism in sequential inactivation of Cryptosporidium parvum with trypsin and UV irradiation

Cryptosporidium, a protozoan parasite, in wastewater presents a major public health concern for water safety. However, bactericidal efficiencies of conventional disinfection methods towards Cryptosporidium oocysts are still hampered owing to the presence of their thick outer wall. In this study, we present a novel UV inactivation process where the efficiency has been significantly enhanced by addition of a trypsin pretreatment stage. Notably, inactivation (log-reduction) of oocysts was noted to be 73.75-294.72% higher than that obtained by UV irradiation alone, under identical conditions. Experimental observations and supporting mechanistic analyses suggest that trypsin led to cleavage of the protein layers on the oocyst wall, facilitating penetration of UV radiation into the oocysts leading to degradation of their genomic DNA (gDNA). The dissociative effect of trypsin on the oocyst wall was indicated by the fact that 64.50% of oocysts displayed early apoptosis after trypsinization. Imaging by scanning electron microscopy indicated that this combined treatment led to substantial disruption of the oocyst coat, deforming their shape. This resulted in the release of cellular proteins and gDNA, their concentrations in bulk solution increasing by 1.22-8.60 times. As UV irradiation time was prolonged, gDNA was degraded into smaller fragments with lower molecular masses. Both laddering and diffuse smear patterns in gel analysis indicated significantly detrimental effects on gDNA and viability of oocysts. Overall, this study demonstrated enhancement of UV inactivation of Cryptosporidium oocysts by trypsin and explored the underlying mechanisms for the process.

Reclamation of ginseng residues using two-stage fermentation and evaluation of their beneficial effects as dietary feed supplements for piglets

Environmental pollution caused by herbal residues, such as ginseng residue (GR), and the huge waste of medicinal ingredients in such residues hinder the development of the pharmaceutical industry. Few studies focused on the biotransformation of GRs and the practical utilization of their bioproducts. In this study, we developed a two-stage fermentation method to optimize GR bioconversion and used the fermented products as dietary supplements for piglets. The tested GR contained abundant lignocelluloses, protein, sugar, and amino acids. Approximately 43.10% of the total lignocelluloses were degraded into sugars by Inonotus obliquus in stage 1 of fermentation. Meanwhile, the sugar content increased by 36.20%, which became the feed for Bacillus subtilis and Saccharomyces cerevisiae in stage 2 of fermentation. These two strains boosted the production of bacterial proteins and other metabolites, including peptides, organic acids, and amino acids. At the end of fermentation, the contents of bioactive compounds significantly increased by 3.18%-21.79%. The dietary supplementation of fermented GR significantly improved the growth performance (6.47%-7.98%), intestinal microbiota, immune function, and healthy status and reduced the diarrhea incidence and noxious gas emission of the piglets. This study provides evidence-based results for the development and deployment of a circular economy between ginseng and livestock industries.

Mechanism comparisons of transport-deposition-reentrainment between microplastics and natural mineral particles in porous media: A theoretical and experimental study

The migration and distribution of microplastic particles (MPs) in the natural environment has attracted global attention in recent years. However, little is known about the transport-deposition-reentrainment differences between MPs and natural mineral particles in porous media. In this study, polystyrene (PS) and silica (SiO₂) particles, representing model MPs and natural mineral particles, respectively, were selected to study the responses of different particle types to changes in specific particle size and flow velocity. Three typical particle sizes and various flow velocities were chosen to compare and delineate the transport-deposition-reentrainment characteristics of PS and SiO₂ in a packed-bed laboratory column. Collector efficiency was calculated using Tufenkji and Elimelech (TE) equation. The particle fractions released from the collector surfaces were predicted using DLVO theory and force analysis. Two types of particles were attached in the secondary minimum, which were either retained on the collector surface or reentrained to the fluid. The staged elution experiment wherein the flow velocity was increased experienced a period of flow shock, thus breaking the force balance of the particle. An increase in the flow velocity resulted in various degrees of particle elution. The breakthrough experiment at a specific flow velocity showed that the corresponding velocity alteration in staged elution experiment contributed to reentrainment to varying extents. When the effect of gravity on particle deposition was negligible, the particle size was larger, and the lower the velocity for releasing the particles. However, the opposite tendency was observed when considering the effect of gravity on particle deposition. Moreover, the deposition, mainly due to gravity, easily causes particle reentrainment as the flow velocity increases. This study further predicts and reveals the nature of transport and deposition differences between MPs and natural mineral particles, which helps to further assess the risk and potential of groundwater contamination with MPs of different sizes.

Development and validation of a nomogram for predicting the risk of nursing home-acquired pneumonia

OBJECTIVE

Nursing home-acquired pneumonia (NHAP) is one of the most frequent infections in nursing homes, with a difficult diagnosis, poor prognosis, and high mortality. The present study was performed to develop and validate a nomogram to predict the risk of NHAP in nursing homes.

MATERIALS AND METHODS

Based on a literature review and clinician's recommendations, we identified and collected the possible factors affecting the occurrence of NHAP. Based on the above factors, a retrospective observational study of 620 nursing home residents' medical records was performed from September 2016 to September 2021. Significant risk factors for NHAP were identified by univariate and multivariate analysis successively. A nomogram was constructed based on the binary logistic regression models to visualize the prediction model. The model's performance was determined by the concordance index (C-index), and the prediction accuracy was evaluated using a calibration curve. Clinical effectiveness was evaluated by decision curve analysis (DCA).

RESULTS

Finally, 12 independent risk factors were identified and assembled into the nomogram. The nomogram had a C-index of 0.958 (95% confidence interval: 0.943-0.972). The area under the receiver operating characteristic curve (AUC-ROC) value of the nomogram was 0.958 (p<0.05), and the calibration plot showed good goodness of fit. The decision curve analysis and clinical impact curve showed good clinical usefulness of the nomogram.

CONCLUSIONS

A nomogram for the early prediction of NHAP, which is easy for nurses to perform in nursing homes, was successfully constructed and validated, and it had a good predictive performance.

Deciphering the influence of multiple anthropogenic inputs on taxonomic and functional profiles of the microbial communities in Yitong River, Northeast China

We conducted the analysis of physicochemical parameters, 16S rRNA amplicon sequencing and real-time quantitative polymerase chain reaction to explore the impact of human inputs on the bacterioplankton communities within a tributary of the largest river flowing through a megacity in northeast China. Agriculture largely accounted for the alteration of diversity and functions of the microbial communities. Furthermore, nitrate and total phosphorus declined at the reservoir outlet. The WWTP effluent discharge caused a decrease of the relative abundance of Actinobacteria and Cyanobacteria, while the impact on the variation of alpha diversity of river microbial community was slight. Carbon fixation and nitrogen cycle varied with the change of land use type. The rare taxa contributed with a predominant role in the response to environmental variables and NH₃-N as well as NO₃^--N were the main environmental factors that drove the shift in the bacterial community. The occurrence of the human-specific fecal indicator was mostly derived from agriculture, and its increase in relative abundance was observed in the WWTP effluent. Thus, our study provides guidance for ecological assessment and management of rivers by revealing the response pattern of river bacterioplankton to multiple types of anthropogenic stressors.

Oxidation of phthalate acid esters using hydrogen peroxide and polyoxometalate/graphene hybrids

Phthalate acid esters (PAEs) have been adsorbed and oxidatively degraded into small molecules including lactic acid (LA), formic acid (FA), H₂O and CO₂ using polyoxometalates (POMs)/graphene hybrids. We demonstrated that super-lower concentrations of PAEs could be oxidized, which was due to their unique structure. POM molecules have been embedded onto graphene to form H₅PMo₁₀V₂O₄₀@surfactant(n)/Graphene(L wt%) (abbreviated as HPMoV@Surf(n)/GO(L wt%)) using surfactants with the carbon chain length n = 2, 4, 6 and 8 for the loading of HPMoV. The coexistence of the graphene and surfactant layer (on HPMoV@Surf(n)/GO(20 wt%)) adsorbed PAE molecules and transported them rapidly to HPMoV active sites. And n values determined the electron transfer ability between graphene and POMs that promoted PAEs oxidation. The loading of POMs on the surface of graphene permitted HPMoV@Surf(n)/GO(L wt%) act as interfacial catalyst which degraded various PAEs (i.e., diethyl phthalate (DEP), diallyl phthalate (DAP) and di (2-ethylhexyl) phthalate (DEHP)) while removed more than 70% of TOC and COD. The degradation of DEP achieved 93.0% with HPMoV@Surf(n)/GO(20 wt%) and H₂O₂, which followed first-order kinetics and the reaction activation energy (Ea) of 23.1 kJ/mol. Further, HPMoV@Surf(n)/GO(20 wt%) showed potential for the removal of PAEs in Wastewater Treatment Plant (WWTP), and the degradation efficiency for PAE (DEP) in secondary effluent achieved 55.0%. In addition, the loading method for POMs on graphene eliminated the leaching of POMs from graphene, and the degradation efficiency could still reach 88.1% after ten recycles.

Critical prognostic factors for poststroke dysphagia: a meta-analysis

OBJECTIVE

Poststroke dysphagia (PSD) is one of the most significant problems after stroke. The prognosis of dysphagia is closely related to the outcomes of stroke. This meta-analysis aimed at identifying and evaluating critical predictors of prognosis for PSD.

MATERIALS AND METHODS

Electronic databases were searched for relevant case-control and cohort studies in which the prognostic factors of PSD were reported. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale. Review Manager 5.3 was used to calculate odds ratios (OR) and their 95% confidence intervals (CI) of the included factors and to perform heterogeneity and sensitivity analyses. Stata 15.1 was used to evaluate publication bias.

RESULTS

Eighteen of 3132 total studies were finally included in this meta-analysis. Ten predictors of PSD were identified, including 2 protective factors and 8 risk factors. Early intervention (OR=0.75, 95% CI=0.61-0.93) and an MRS (modified Rankin scale) score of 0 before onset (OR=0.58, 95% CI=0.47-0.71) were related to a better prognosis of PSD. The risk factors ranked by pooled OR values were aspiration (OR=7.64, 95% CI=5.94-9.82), brainstem injury (OR=4.82, 95% CI=3.01-7.72), severity of stroke (OR= 3.06, 95% CI=1.69-5.53), bihemispheric injury (OR=3.0, 95% CI=1.67-5.40), older age (OR=1.75, 95% CI=1.50-2.04), malnutrition (OR=1.36, 95% CI=1.22-1.53), severe dysphagia on admission (OR=1.16, 95% CI=1.03-1.29), and reduced level of consciousness (OR=1.03, 95% CI=1.00-1.07).

CONCLUSIONS

Prognostic factors for a good outcome of PSD included early intervention and an MRS score of 0 before onset. Aspiration, brainstem injury, severe stroke and bihemispheric injury are the four most significant predictors of poor prognosis in PSD. Identifying these prognostic factors should help clinicians to better detect patients at risk and provide effective interventions for PSD.

Spatial distribution and potential sources of microplastics in the Songhua River flowing through urban centers in Northeast China

Microplastics (MPs) have elicited increasing concerns in freshwater systems worldwide. However, little information is available on the MP pollution in the Songhua River, the third largest river in China. And the understanding of the sources and pathways of MPs is limited. In this study, MPs were sampled from river water and wastewater treatment plants in five cities along the Songhua River to investigate the occurrence, spatial distribution, characteristics, and potential sources of MPs. Polyethylene, polypropylene and polystyrene accounted for more than 95% of the total MPs. MP pollution was determined to be spatially heterogeneous. The concentration of MPs in the urban center was always considerably higher than that in the upper reach, and irregular variation was observed from the urban center to the lower reach for each city. Urbanization was one of the primary driving forces of spatial variability. Statistically significant positive correlations (p-value < 0.05) were noted between the average concentration of MPs in river water and population density (p = 0.0023) and number of industrial enterprises above designated size (p = 0.0042) of each city. Line and fiber were the major shapes, and white was the most dominant color. Large (1-5 mm) and small (≤ 1 mm) MP particles accounted for 50% each. Multiple correspondence analysis as a new methodological approach was conducted to elucidate the sources of MPs for the first time. The potential sources of MPs included daily use, fishing, agricultural, and industrial productions. This work provides information about MP contamination for future studies on freshwater systems and new insights into the source apportionment of MPs.

Stepwise extraction of Fe, Al, Ca, and Zn: A green route to recycle raw electroplating sludge

Electroplating sludge is a hazardous waste produced in large quantities in the electroplating industry during production. It is rich in heavy metal resources and can be recovered as value-added heavy metal products. To recover Zn in electroplating sludge, Fe/Al/Ca impurities were effectively removed as hematite, boehmite, and calcium sulfate, respectively, via a facile hydrothermal method with reduction of nitric acid by addition of glucose. After the sludge was dissolved in nitric acid, the generated solution contained 6.1 g/L of Zn, 2.2 g/L of Fe, 2.5 g/L of Al, and 2.9 g/L of Ca. First, approximately 100% Fe was extracted as hematite nanoparticles containing 94.6 wt% Fe₂O₃ after the solution was treated at 190 °C for 6 h. Second, when the temperature was elevated to 270 °C, nearly 99% Al was isolated as boehmite particles containing 95.2 wt% Al₂O₃. Third, more than 98% Ca was removed as anhydrite, which contained 95.9 wt% CaSO₄, by adding sulfuric acid. During the steps, the total loss of Zn was less than 3%, and 5.75 g/L of residual Zn was recovered as zincite containing 92.2 wt% ZnO by adjusting the pH to 8. The dissolved Fe, Al, and Ca impurities were successfully removed as purified hematite, boehmite, and anhydrite, respectively, through the stepwise separation method by adjusting reaction temperatures and pH. The high content of Zn in the electroplating sludge was finally purified as zincite.

Outcomes Following Hypofractionated Stereotactic Radiotherapy to the Cavity After Surgery for Melanoma Brain Metastases

AIMS

Hypofractionated stereotactic radiotherapy (HSRT) to the cavity after surgical resection of brain metastases improves local control. Most reported cohorts include few patients with melanoma, a population known to have high rates of recurrence and neurological death. We aimed to assess outcomes in patients with melanoma brain metastases who received HSRT after surgery at two Australian institutions.

MATERIALS AND METHODS

A retrospective analysis was carried out including patients treated between January 2012 and May 2020. HSRT was recommended for patients with melanoma brain metastases at high risk of local recurrence after surgery. Treatment was delivered using appropriately commissioned linear accelerators. Routine follow-up included surveillance magnetic resonance imaging brain every 3 months for at least 2 years. Primary outcomes were overall survival, local control, incidence of radiological radionecrosis and symptomatic radionecrosis.

RESULTS

There were 63 cavities identified in 57 patients. The most common HSRT dose prescriptions were 24 Gy in three fractions and 27.5 Gy in five fractions. The median follow-up was 32 months in survivors. Local control was 90% at 1 year, 83% at 2 years and 76% at 3 years. Subtotal brain metastases resection (hazard ratio 12.5; 95% confidence interval 1.4-111; P = 0.0238) was associated with more local recurrence. Overall survival was 64% at 1 year, 45% at 2 years and 40% at 3 years. There were 10 radiological radionecrosis events (16% of cavities) during the study period, with 5% at 1 year and 8% at 2 years after HSRT. The median time to onset of radiological radionecrosis was 21 months (range 6-56). Of these events, three became symptomatic (5%) during the study period at a median time to onset of 26 months (range 21-32).

CONCLUSION

Cavity HSRT is associated with high rates of local control in patients with melanoma brain metastases. Subtotal resection strongly predicts for local recurrence after HSRT. Symptomatic radionecrosis occurred in 5% of cavities but increased to 8% of longer-term survivors.

Cu transport and distribution in different cellular fractions of Klebsiella oxytoca strain CAV 1374

This study elucidated copper (Cu) transport and trafficking mechanisms at the cellular interface using the Cu-resistant strain Klebsiella oxytoca CAV 1374. The optimum conditions for biosorption were determined by investigating uptake rates due to initial pH, initial Cu concentrations, and maximum tolerated concentrations (MTC) of Cu. Cellular fraction analysis and depth-profiling XPS were used to comprehensively evaluate the spatial-temporal distribution of Cu on cellular interfaces during biosorption. Potential uptake mechanisms were then further examined by biosorption kinetics analyses, ion exchange experiments, FTIR analysis, and K⁺ channel blocking experiments. The results indicated that Cu was primarily absorbed by extracellular polymeric substances through chemical interactions and little Cu penetrated inside cells under low Cu stress conditions (≤20 mg/L). In contrast, an intracellular rate-controlling physical interaction was predominant under high Cu stress conditions (≥30 mg/L). Further, Cu²⁺ could be bound by functional groups, followed first by replacement of Ca²⁺ at the cell surface. Subsequently, some of the Cu²⁺ in cell walls was reduced to Cu⁺, and only Cu⁺ could then penetrate into cell membranes. These results indicate that strain Klebsiella oxytoca CAV 1374 is a suitable biosorbent agent for Cu removal and can provide critical insights into Cu-uptake mechanisms of microorganisms.

Bactericidal efficiency and photochemical mechanisms of micro/nano bubble-enhanced visible light photocatalytic water disinfection

Microbial contamination of water in the form of highly-resistant bacterial spores can cause a long-term risk of waterborne disease. Advanced photocatalysis has become an effective approach to inactivate bacterial spores due to its potential for efficient solar energy conversion alongside reduced formation of disinfection by-products. However, the overall efficiency of the process still requires significant improvements. Here, we proposed and evaluated a novel visible light photocatalytic water disinfection technology by its close coupling with micro/nano bubbles (MNBs). The inactivation rate constant of Bacillus subtilis spores reached 1.28 h^-1, which was 5.6 times higher than that observed for treatment without MNBs. The superior performance for the progressive destruction of spores' cells during the treatment was confirmed by transmission electron microscopy (TEM) and excitation-emission matrix (EEM) spectra determination. Experiments using scavengers of reactive oxygen species (ROSs) revealed that H₂O₂ and •OH were the primary active species responsible for the inactivation of spores. The effective supply of oxygen from air MNBs helped accelerate the hole oxidation of H₂O₂ on the photocatalyst (i.e. Ag/TiO₂). In addition, the interfacial photoelectric effect from the MNBs was also confirmed to contribute to the spore inactivation. Specifically, MNBs induced strong light scattering, consequently increasing the optical path length in the photocatalysis medium by 54.8% at 700nm and enhancing light adsorption of the photocatalyst. The non-uniformities in dielectricity led to a high-degree of heterogeneity of the electric field, which triggered the formation of a region of enhanced light intensity which ultimately promoted the photocatalytic reaction. Overall, this study provided new insights on the mechanisms of photocatalysis coupled with MNB technology for advanced water treatment.

Fabrication of ordered mesoporous POMs/SiO2-NH2 nanofibers for production of DFF from 5-HMF for cellulose wastewater resource recovery

5-hydroxymethylfurfural (5-HMF) is a biomass cellulose platform product that can be transformed into the valuable resource 2,5-diformylfuran (DFF). Polyoxometalates (POMs) have important applications in resource recovery technologies and cellulose wastewater treatment. Ordered mesoporous H₅PMo₁₀V₂O₄₀/SiO₂-NH₂ (wt%) nanofibers (HPMoV/meso-SiO₂-NH₂ (wt%)) were synthesized by the combining in-situ fabrication and electrospinning techniques, using H₅PMo₁₀V₂O₄₀ (HPMoV) and organic-silica as precursors. Aiming the recovery and transformation of 5-HMF, aerobic oxidation of 5-HMF was explored using these nanofibers as catalysts, while the best yield of DFF (90.0%) was obtained upon HPMoV/meso-SiO₂-NH₂ (23%) nanofibers after 8 h at 120 °C using oxygen (1.0 MPa). The selectivity to DFF was improved by changing the hydrophilicity of the HPMoV@SiO₂ nanofibers to hydrophobicity by modifying SiO₂ nanofibers with -NH₂R compared to mesoporous SiO₂ nanofibers, which allowed the formed DFF to be isolated. In the recycling test, HPMoV@SiO₂-NH₂ showed good performance, and no leaching of active sites from SiO₂-NH₂ due to the interactions between them occurred after 10 cycles. The production of DFF from the real cellulosic wastewater was obtained with 118% yield based on 5-HMF conversion by HPMoV/meso-SiO₂-NH₂ (23) and oxygen, which was contributed to the one-pot conversion of sugar, furan and 5-HMF in the wastewater.

Enhanced Photocatalytic Water Decontamination by Micro-Nano Bubbles: Measurements and Mechanisms

Despite recent advancements in photocatalysis enabled by materials science innovations, the application of photocatalysts in water treatment is still hampered due to low overall efficiency. Herein, we present a TiO₂ photocatalytic process with significantly enhanced efficiency by the introduction of micro-nano bubbles (MNBs). Notably, the removal rate of a model organic contaminant (methylene blue, MB) in an air MNB-assisted photocatalytic degradation (PCD) process was 41-141% higher than that obtained in conventional macrobubble (MaB)-assisted PCD under identical conditions. Experimental observations and supporting mechanistic modeling suggest that the enhanced photocatalytic degradation is attributed to the combined effects of increased dissolution of oxygen, improved colloidal stability and dispersion of the TiO₂ nanocatalysts, and interfacial photoelectric effects of TiO₂/MNB suspensions. The maximum dissolved oxygen (DO) concentration of the MNB suspension (i.e., 11.7 mg/L) was 32% higher than that of an MaB-aerated aqueous solution (i.e., 8.8 mg/L), thus accelerating the hole oxidation of H₂O on TiO₂. We further confirmed that the MNBs induced unique light-scattering effects, consequently increasing the optical path length in the TiO₂/MNB suspension by 7.6%. A force balance model confirmed that a three-phase contact was formed on the surface of the bubble-TiO₂ complex, which promoted high complex stability and PCD performance. Overall, this study demonstrates the enhanced photocatalytic water decontamination by MNBs and provides the underlying mechanisms for the process.

An integrated approach using ozone nanobubble and cyclodextrin inclusion complexation to enhance the removal of micropollutants

Ozone (O₃) has been widely used for the elimination of recalcitrant micropollutants in aqueous environments, due to its strong oxidation ability. However, the utilization efficiency of O₃ is constrained by its low solubility and short half-life during the treatment process. Herein, an integrated approach, using nanobubble technology and micro-environmental chemistry within cyclodextrin inclusion cavities, was studied in order to enhance the reactivity of ozonisation. Compared with traditional macrobubble aeration with O₃ in water, nanobubble aeration achieved 1.7 times higher solubility of O_3, and increased the mass transfer coefficient 4.7 times. Moreover, the addition of hydroxypropyl-β-cyclodextrin (HPβCD) further increased the stability of O₃ through formation of an inclusion complex in its molecule-specific cavity. At a HPβCD:O₃ molar ratio of 10:1, the lifespan of O₃ reached 18 times longer than in a HPβCD-free O₃ solution. Such approach accelerated the removal efficiency of the model micropollutant, 4-chlorophenol by 6.9 times, compared with conventional macrobubble ozonation. Examination of the HPβCD inclusion complex by UV-visible spectroscopy and Nuclear Magnetic Resonance analyses revealed that both O₃ and 4-chlorophenol entered the HPβCD cavity, and Benesi-Hildebrand plots indicated a 1:1 stoichiometry of the host and guest compounds. Additionally, molecular docking simulations were conducted in order to confirm the formation of a ternary complex of HPβCD:4-chlorophenol:O₃ and to determine the optimal inclusion mode. With these results, our study highlights the viability of the proposed integrated approach to enhance the ozonation of organic micropollutants.

Resource Recycling of Mn-Rich Sludge: Effective Separation of Impure Fe/Al and Recovery of High-Purity Hausmannite

Groundwater treatment sludge is a Fe/Mn-rich waste generated in mass production in a groundwater treatment plant for potable water production. The conventional disposal of sludge, such as direct discharge into river/lake, sea, and landfill, is not environmentally sustainable. Herein, a novel method was proposed to effectively separate Fe/Al and recover Mn via a combined hydrochloric acid leaching and hydrothermal route. The sludge contained 14.6% Fe, 6.3% Mn, and 11.5% Al and was first dissolved in 5 M HCl to prepare a leaching solution. Second, the leaching solution was hydrothermally treated, in which 97.1% Fe and 94.8% Al were precipitated as hematite and boehmite and more than 98% Mn was kept. Increasing the reaction temperature to 270 °C was beneficial for Fe/Al removal. With the consumption of abundant H+, the reaction of added glucose and nitrate accelerated as the temperature increased. An optimal pH was utilized for Fe/Al hydrolysis and crystallization, leading to extensive removal of Fe/Al. Third, the residual solution was adjusted to pH 8.3 with NaOH, and approximately, 99.2% Mn was removed as hausmannite with a Mn content of 63.6%. This method exhibited efficient separation of impure Fe/Al from Mn-rich groundwater treatment plant iron mud, and the recycled high-purity hausmannite was a marketable active pharmaceutical ingredient.

A facile calcination conversion of groundwater treatment sludge (GTS) as magnetic adsorbent for oxytetracycline adsorption

In this paper, groundwater treatment sludge (GTS) was recycled as a magnetic adsorbent via a facile calcination process without adding any reductant. The prepared magnetic adsorbents (MAs) were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS), vibrating sample magnenometer (VSM) and Mössbauer spectroscopy. The results showed that GTS comprised 33.2% Fe, 1.4% Al and 6.2% Si, and exhibited a weak saturation magnetization of 0.0008 emu/g. Without NaOH, the GTS calcinated at 700 and 500 °C were well magnetized with Ms of 20.1 and 7.1 emu/g, separately, but exhibited a low Ms of 0.43 emu/g at 300 °C. By adding NaOH powder, the Ms of GTS apparently increased to 4.9 emu/g after calcination at 300 °C, and further to 8.5 emu/g at 500 °C. In GTS, about 96.1% Fe was involved in ferrihydrite form. The Ms of calcinated GTS was accompanied with the phase transformation of ferrihydrite to maghemite. Si/Al oxides in GTS coordinated on the surface sites of ferrihydrite and inhibited the conjunction and phase transformation of adjacent ferrihydrite particles, but were effectively desorbed as in the presence of NaOH. Na500, preparing by calcinating GTS at 500 °C with NaOH, showed an optimal total surface sites (Hs) of 0.65 mmol/g. Oxytetracycline (OTC) was used as a target for studying the adsorption characteristics of synthetic magnetic adsorbents and a high adsorption capacity of oxytetracycline of 862.1 mg/g in comparison with the other calcinated GTS, and the adsorption data was consistent with the Langmuir model. By adding 6 g/L Na-500, approximately 100% of oxytetracycline and tetracycline and nearly 40% total organic carbon were removed from real pharmaceutical wastewater. With the method, GTS can be converted in mass production to magnetic adsorbent that exhibits effective application in pharmaceutical wastewater treatment.

Evolution of dissolved organic matter during artificial groundwater recharge with effluent from underutilized WWTP and the resulting facilitated transport effect

Currently, the interaction between contaminants and dissolved organic matter (DOM) during artificial groundwater recharge (AGR) with effluent from underutilized wastewater treatment plant (WWTP) is unclear. The present study investigated DOM evolution in this AGR scenario. The DOM composition in the inflow was identified to be distinct to that of the outflow due to the release of soil humic acid (HA). The soluble soil HA was then extracted and used in co-transport experiments with tetracycline (TC). The separated HA transport through the soil column exhibited high mobility with mass recovery >92.5% in the effluent. Following the mixing of injected TC and HA, the TC breakthrough in the column increased with HA concentration. TC was heavily adsorbed by the soil without the presence of HA, yet the retention ratios decreased from 63.60% to 53.30% for the HA range of 0-20 mg L^-1. An advection-dispersion-retention (ADR) numerical model was developed to effectively quantify the HA-TC co-transport, with results demonstrating the reduction in the TC attachment rate with increasing HA concentrations. Furthermore, batch adsorption experiments, kinetics and isotherms models, and FTIR spectra analysis were implemented to determine the underlying mechanism. The co-transport behavior was observed to be a function of the relative soil sorption affinity between HA and TC. The weaker sorption of the HA-coated TC compared to the separated TC consequently suggests that HA is likely to compete for available soil adsorption sites. Thus, the release of soil humus during AGR can potentially facilitate the transport of the introduced contaminants.

Photo-electrochemical Osmotic System Enables Simultaneous Metal Recovery and Electricity Generation from Wastewater

Global depletion of natural resources provides an impetus for developing low-cost, environmentally benign technologies for the recovery of valuable resources from wastewater. In this study, we present an autonomous photo-electrochemical osmotic system (PECOS) that can recover a wide range of metals from simulated metal-laden wastewater with sunlight illumination while generating electricity. The PECOS comprises a draw solution chamber with a nickel nanoparticle-functionalized titanium nanowire (Ni-TiNA) photoanode, a feed solution chamber containing synthetic wastewater with an immersed carbon fiber cathode, and a forward osmosis (FO) membrane mounted between the chambers as a separator. Using a Na₂-EDTA anolyte as a draw solution at neutral pH, we demonstrate that a sunlit PECOS achieves copper recovery at a rate of 51 g h^-1 per m^-2 of membrane area from simulated copper-laden wastewater while simultaneously producing a maximum power density of 228 mW m^-2. Moreover, because of the osmotic pressure difference generated by the photo-electrochemical reactions, the PECOS reduces the wastewater volume by extracting fresh water through the FO membrane at a water flux of 0.84 L m^-2 h^-1. We further demonstrate the feasibility of the PECOS in recovering diverse metals from a simulated metal-laden industrial wastewater under sunlight irradiation. Our proof-of-concept PECOS prototype provides a sustainable technological solution that leverages sunlight in an electrochemical osmotic system to recover multiple resources from wastewater.

Pilot study on urban sewage treatment with micro pressure swirl reactor

This study aimed to propose a new type of micro-pressure swirl reactor (MPSR) to treat urban sewage. The MPSR could form a stable swirl in the reactor, and realized the coexistence of anaerobic, anoxic, and aerobic zones in a single aeration tank. The pilot study showed that MPSR achieved high removal efficient of SS, COD, NH₄⁺-N, TN, TP under the conditions of drastic fluctuation in influent quality and temperature, and the average removal rate were 88.58%, 93.32%, 94.47%, 73.19%, 96.16%. The relative high abundance of Thermomonas, Thaurea, and Dechloromonas, etc, guaranteed the denitrification efficiency of the MPSR, and Dechloromonas was the main phosphorus removal bacteria in the system. The study confirmed the rationality of the structural design of the MPSR, and it was excellent in sewage treatment and stability.

Upcycling of groundwater treatment sludge to an erdite nanorod as a highly effienct activation agent of peroxymonosulfate for wastewater treatment

Groundwater treatment sludge is an Fe-rich waste continuously generated in large amounts through potable water production at groundwater treatment plants. In this study, the sludge was converted to erdite nanorod particles via a one-step hydrothermal route with only adding Na₂S. The sludge was a mixture of ferrihydrite, hematite and Si/Al oxides. After hyddrothemal treatment, erdite was primarily formed from ferrihydrite, which accounted for 91.2% of the Fe species in the sludge, whereas approximately 8.8% of hematite accounted for the Fe species that remained before and after the reaction. The produced erdite nanorods were approximately 200 nm in diameter and 1-3 μm in length. They also exhibited a superior efficiency in peroxymonosulfate (PMS) activation. Nearly 100% quinoline removal (initail concentration = 10 mg L^-1) was achieved when the eridite nanorods were used with PMS. The removal rate of quinoline was much higher than that of raw sludge, nano-scale zero-valent iron, FeS, hematite and magnetite. The erdite nanorods or the PMS alone had a quinoline removal rate of less than 20%. The erdite nanorods were spontaneously hydrolysed to generate Fe²⁺ for PMS activation and to form S species for the reductive cycling of Fe³⁺ to Fe²⁺, which likely promoted PMS activation. This study not only highlighted a facile method to recycle the sludge for erdite nanorod preparation but also presented a novel nanomaterial that could efficiently activate PMS for organic wastewater treatment.

Electrochemical-Osmotic Process for Simultaneous Recovery of Electric Energy, Water, and Metals from Wastewater

A highly-efficient, autonomous electrochemical-osmotic system (EOS) is developed for simultaneous recovery of electric energy, water, and metals from wastewater. We demonstrate that the system can generate a maximum electric power density of 10.5 W m^-2 using a spontaneous Fe/Cu²⁺ galvanic cell, while simultaneously achieving copper recovery from wastewater. With an osmotic pressure difference generated by the deployed electrochemical reactions, water is osmotically extracted from the feed solution with the EOS at a water flux of 5.1 L m^-2 h^-1. A scaled-up EOS realizes a power density of 105.8 W per m^-3 of treated water to light an LED over 24 h while also enhancing water extraction and metal recovery. The modularized EOS obtains ultrahigh (>97.5%) Faradaic efficiencies under variable operating conditions, showing excellent system stability. The EOS is also versatile: it can recover Au, Ag, and Hg from wastewaters with simultaneous electricity and water coproduction. Our study demonstrates a promising pathway for realizing multiresource recycling from wastewater by coupling electrochemical and osmosis-driven processes.

Risk of physical clogging induced by low-density suspended particles during managed aquifer recharge with reclaimed water: Evidences from laboratory experiments and numerical modeling

How to reduce the risk of physical clogging is the most significant challenge during managed aquifer recharge (MAR). The prediction of occurrence and development of physical clogging has received increasing attention. In this study, chlorinated secondary wastewater (SW) was recharged into a laboratory column filled with quartz sands. The results showed that the continuous injection of reclaimed water caused a significant reduction in hydraulic conductivity by about 86% in porous media, during the 50-h injection process. The reduction was attributed to physical clogging resulting from the deposition of suspended particles with a flocculent and reticular structure, significantly increasing the surface area and the effective volume of the particle deposits. A numerical model was established based on the mass balance equations for liquid and suspended particles, coupling the particle transport-deposition model and the expressions describing the relationships between the porosity, hydraulic conductivity (K), and the concentration of deposited particles; the model was used to obtain a quantitative description of the temporal and spatial distribution of physical clogging. The bulk factor and the attachment and detachment coefficients were calibrated simultaneously. The model results provided an improved understanding of the influence degree of the three parameters on the physical clogging process. The sensitivity analysis results showed that the bulk factor had the largest sensitivity among the three parameters. In addition, a significant correlation was observed between the simulated data and the experimental data (R² > 0.90, p < 0.01). The proposed numerical model provides a meaningful guidance tool for assessing and predicting the risk of physical clogging induced by low-density floc particles during artificial recharge with reclaimed water at a large-scale site.

Effective column adsorption of triclosan from pure water and wastewater treatment plant effluent by using magnetic porous reduced graphene oxide

The ubiquitous presence of triclosan (TCS) in aquatic systems is of great concern. In the present work, magnetic porous reduced graphene oxide (MPrGO) was synthesized via in situ chemical co-precipitation of Fe³⁺and porous graphene oxide and, was used as an adsorbent for the removal of TCS with μg/L level from both pure water and wastewater treatment plant (WWTP) effluent by conducting with continuous flow fixed column. The BET surface area of MPrGO (1070 m²/g) was about tenfold higher than that of commercial powder activated carbon (PAC). Fast adsorption equilibrium can be reached within 20 s, the maximum adsorption capacity of TCS on MPrGO reached 1105.8 mg/g, and the sorbent can be regenerated for reusability about 5 cycles. The breakthrough time was 50 days for the bed depth of 2.3 mm at the inlet TCS concentration of 100 μg/L. MPrGO exhibited a much higher affinity toward TCS than PAC as the breakthrough time for MPrGO was 6.5 times longer than that for PAC. The Thomas and Yoon-Nelson models provide a better fitting curve than that by the Adams-Bohart model. High TCS adsorption capacity of 935.3 mg/g was calculated from WWTP effluent.

Novel application of a Z-scheme photocatalyst of Ag3PO4@g-C3N4 for photocatalytic fuel cells

A composite of Ag₃PO₄@g-C₃N₄ with the Z-scheme structure was synthesized, and used as the photoanode in a photocatalytic fuel cell (PFC). With the help of the Z-scheme design, both the degradation of tetracycline and the output of maximum power density (P_max) were greatly enhanced in this PFC system. The degradation rate of tetracycline in the Ag₃PO₄@g-C₃N₄ PFC was 2.53 times and 3.65 times that in the PFC systems with the Ag₃PO₄ photoanode and the g-C₃N₄ photoanode, respectively. The P_max of the Ag₃PO₄@g-C₃N₄ PFC was 6.06 μW cm^-2, which was 1.46 times and 90.4 times that of the Ag₃PO₄ PFC (4.16 μW cm^-2) and the g-C₃N₄ PFC (0.067 μW cm^-2), respectively. The possible mechanism was proposed. The Z-scheme photoanode could not only contribute to the separation of photogenerated carriers to achieve a high photocatalytic activity, but also reserve a good redox capacity. Additionally, aeration played an important role on the PFC performance. It was demonstrated that N₂ purging facilitated the electricity generation, while O₂ purging promoted the pollutant degradation.

Fasudil alleviates hepatic fibrosis in type 1 diabetic rats: involvement of the inflammation and RhoA/ROCK pathway

OBJECTIVE

Rho-associated kinases (ROCKs) are recognized to be involved in many pathophysiological processes caused by hyperglycemia. We performed experiments to evaluate the effects of fasudil, the Rho/ROCK inhibitor, on preventing hepatic fibrosis in type 1 diabetic rats and to elucidate the underlying mechanisms.

MATERIALS AND METHODS

Sprague-Dawley (SD) rats were randomly divided into five groups: normal control (NC), untreated diabetic (DM), low-dose fasudil-treated (L-Fas), high-dose fasudil-treated (H-Fas) and captopril-treated (Cap) groups. Streptozotocin was injected to establish the diabetes model. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were analyzed. Hematoxylin and eosin (HE) and Masson's trichrome staining were used for histological observations. The expression of transforming growth factor-β (TGF-β1), metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinase-1 (TIMP-1), collagen type Iα (Coll α1), nuclear factor-kappa B (NF-κB) and ROCK-1 were measured to investigate the mechanisms involved in fibrosis.

RESULTS

The DM group exhibited hepatic fibrosis with remarkable liver damage and inflammation reaction by the activation of the NF-κB pathway. Treatment with fasudil or captopril suppressed not only the inflammation reaction but also the accumulation of the extracellular matrix due to the downregulation of TGF-β1 and MMP-9/TIMP-1, which induces the amelioration of the liver fibrosis with diabetes. Furthermore, fasudil significantly attenuated the activation of ROCK-1 and NF-κB in the livers of diabetic rats.

CONCLUSIONS

These results suggest that fasudil exert anti-inflammation actions and markedly decrease the accumulation of extracellular matrix. Fasudil is a good candidate agent for treating hepatic fibrosis in diabetes.

Dracorhodin perchlorate protects pancreatic β-cells against glucotoxicity- or lipotoxicity-induced dysfunction and apoptosis in vitro and in vivo

Glucotoxicity or lipotoxicity leads to hyperglycemia and insulin secretion deficiency, which are important causes for the onset of type 2 diabetes mellitus (T2DM). Thus, the restoration of β-cell function is a long-sought goal in diabetes research. Previous studies have implicated pancreatic and duodenal homeobox 1 gene (Pdx1) in β-cell function and insulin secretion. In this study, we established a Pdx1 promoter-dependent luciferase system and identified the natural compound dracorhodin perchlorate (DP) as an effective promotor of Pdx1 expression. We further demonstrated that DP could significantly inhibit β-cell apoptosis induced by 33 mm glucose or 200 μm palmitate by interfering with endoplasmic reticulum stress and mitochondrial pathways and enhance insulin secretion as well. These effects were associated with enhanced activities of Erk1/2, which in turn promoted Pdx1 expression and increased the ratio of Bcl2/Bax, since inhibition of the Erk1/2 pathway abolished the DP-induced expression of Pdx1 and suppression of apoptosis. In addition, our in vivo results in diabetic mice indicated that DP treatment lowered blood glucose, raised insulin levels, enhanced Pdx1 expression and increased islet size and number in the pancreas of diabetic mice. Our findings suggest that Pdx1 is a potential target molecule of DP in the treatment of T2DM via the inhibition of glucotoxicity- or lipotoxicity- induced β-cell apoptosis and the attenuation of insulin secretion dysfunction.

Intensifying ozonation treatment of municipal secondary effluent using a combination of microbubbles and ultraviolet irradiation

Ozonation treatment of municipal secondary effluent is complicated by the low solubility of ozone and inefficient production of hydroxyl free radicals from ozone decomposition. To resolve these problems, this study investigated methods for intensifying ozonation treatment, using a combination of microbubbles and ultraviolet (UV) irradiation (UV/MBO). The high efficiency of the method was illustrated by treating river water containing refractory components derived from secondary effluent in a wastewater treatment plant. The results showed that the ozone mass transfer coefficient in a microbubble system was an order of magnitude compared with a conventional macrobubble system at the initial stage. The amount of ·OH generated during the treatment was quantified using a fluorescent probe analysis. The amount of ·OH in the UV/MBO system was almost 2-6 times more than the amount found with conventional ozonation using macrobubbles (CO), CO with UV irradiation (UV/CO), and microbubble ozonation (MBO) units. The UV/MBO system achieved chemical oxygen demand (COD), UV₂₅₄, and UV₄₀₀ removal performance rates of up to 37.50%, 81.15%, and 94.74% respectively. These levels were 2-36% higher than those in other systems. The coupling UV/MBO treatment significantly reduced all five categories of substances according to EEM spectra and fluorescence regional integration. The distribution of fractions with different molecular weights (MW) was altered and the UV₂₅₄ of MW (< 500 Da) increased by 15.8%. The biodegradability of the water was significantly improved, as indicated by the TOC/UV₂₅₄. This is ascribed to the enhanced degradation of refractory organics in the water. The combination of the UV/microbubble technique with ozonation could provide an efficient approach for advanced wastewater treatment. Graphical abstract.

Responses to copper stress in the metal-resistant bacterium Cupriavidus gilardii CR3: a whole-transcriptome analysis

Microbial metal-resistance mechanisms are the basis for the application of microorganisms in metal bioremediation. Despite the available studies of bacterial molecular mechanisms to resistance metals ions (particularly copper), the understanding of bacterial metal resistance is very limited from the transcriptome perspective. Here, responses of the transcriptome (RNA-Seq) was investigated in Cupriavidus gilardii CR3 exposed to 0.5 mM copper, because strain CR3 had a bioremoval capacity of 38.5% for 0.5 mM copper. More than 24 million clean reads were obtained from six libraries and were aligned against the C. gilardii CR3 genome. A total of 310 genes in strain CR3 were significantly differentially expressed under copper stress. Apart from the routine copper resistance operons cus and cop known in previous studies, Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses of differentially expressed genes indicated that the adenosine triphosphate-binding cassette transporter, amino acid metabolism, and negative chemotaxis collectively contribute to the copper-resistant process. More interestingly, we found that the genes associated with the type III secretion system were induced under copper stress. No such results were reordered in bacteria to date. Overall, this comprehensive network of copper responses is useful for further studies of the molecular mechanisms underlying responses to copper stress in bacteria.

Fast degradation of phthalate acid esters by polyoxometalate nanocatalysts through adsorption, esterolysis and oxidation

A novel route was created to facilitate the degradation of diethyl phthalate (DEP) upon micellar polyoxometalate (POM) catalysts and H₂O₂. The best catalytic activity was obtained using [C₁₆H₃₃N(CH₃)₃]H₄PMo₁₀V₂O₄₀ (N-hexadecyl-N,N,N-trimethylammonium tetrahydrogen decamolybdo-divanadophosphate, abbreviated as (CTA)H₄PMoV) with 90.2% degradation efficiency within 30 min, while the chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiency were about 77.7% and 74.3% within 40 min. The highest efficiency was attributed to the concentration of DEP by amphiphilic POM catalyst, coupling with its strong Brønsted acidity and higher redox potential to catalyze esterolysis and oxidation of DEP. This allowed the phthalate acid esters (PAEs) with long carbon chains in super low concentration of 0.03 μM to be efficiently decomposed. The above synergistic effects explored DEP being degraded into ethanol, lactic acid and CO₂, which were non-toxic to the water surroundings. And the reaction activation energy (Ea) of 12.49 kJ/mol was obtained upon the degradation of DEP with (CTA)H₄PMoV followed first-order kinetics. Meanwhile, (CTA)H₄PMoV acted as a heterogeneous catalyst, which showed long duration and higher stability with only 3.7% loss amount during ten recycles.

Valorization of manganese-containing groundwater treatment sludge by preparing magnetic adsorbent for Cu(II) adsorption

Mn-containing sludge from groundwater treatment was converted to magnetic particles (MPs) via a one-step hydrothermal method using sodium ascorbate (SA) as the reductant. The MPs were characterized by X-ray diffraction spectroscopy, Mössbauer spectroscopy, X-ray fluorescence spectroscopy, magnetometry and Gran titration and the results showed that magnetic jacobsite was obtained as an intermediate product in transformation of Fe/Mn oxides to siderite and rhodochrosite. When the molar ratio of SA to Mn in the sludge was two, the produced MPs-2 contained a mixture of ferrihdyrite, hematite, jacobsite and Si/Al oxides, and could magnetize at 2.4 emu/g. Ferrihydrite content in MPs decreased with increase of the SA/Mn molar ratio, leading to decrease of the surface sites concentration (H_s). Thus, MPs-2 contained optimized H_s of 6.7 mmoL/g and a desirable adsorption capacity of Cu(II) (73.1 mg/g). The adsorption isotherms of MPs-2 on Cu(II) complied with the Langmuir model and the adsorption kinetics fitted well with the pseudo-second-order model. The major mechanism of adsorption was cationic exchange of the coordinated H and Na ions on MPs-2 surface sites with the Cu(II) ions. This study was the first time to report preparation of MPs by recycling Mn-containing sludge, which could be used as a high-capacity and low-cost adsorbent in treatment of heavy metal-containing wastewater.

High-Performance TiO₂ Nanotubes/Poly(aryl ether sulfone) Hybrid Self-Cleaning Anti-Fouling Ultrafiltration Membranes

A series of novel self-cleaning hybrid photocatalytic ultrafiltration (UF) membranes were fabricated to separate polyacrylamide, which is widely used as a commercial flocculant. To maximize the self-cleaning and anti-fouling properties of hybrid membranes, high surface area TiO₂ nanotubes (TNTs) with excellent photocatalytic activity were homogeneously introduced into a poly(aryl ether sulfone) matrix by chemical bonds. The chemical structure, micromorphology, hydrophilicity, separation efficiency, fouling behavior, and self-cleaning property of the prepared hybrid membranes were well characterized and evaluated. For the optimal sample, the flux recovery ratio increased from ~40% to ~80% after simulated sunlight irradiation for 20 min, which was attributable to the homogeneous dispersion and efficient photocatalytic degradation ability of TNTs. Furthermore, the intelligent fabrication strategy enhanced the anti-aging ability of the hybrid membranes via the use of a fluorine-containing poly matrix. This work provided new insight into the fabrication of high-performance self-cleaning inorganic/organic hybrid membranes.

Resource recovery of wastewater treatment sludge: synthesis of a magnetic cancrinite adsorbent

Water treatment sludge, which is mechanically dewatered and landfilled as solid waste, is considerably generated in water plants for potable water production. Herein, a novel route to hydrothermally convert this sludge into magnetic particles (MPs) is demonstrated. The sludge comprised amorphous aggregates with a relatively high Al/Si ratio of 3.7 and low Fe content of 8.5 wt%. After hydrothermal treatment, the Al/Si ratio of the MPs was approximated to 1, which was unaffected as the NaOH concentration increased from 2 M to 4 M or 6 M. The amorphous sludge was converted to MPs in the following order: spherical sodalite with a diameter of 3–5 μm, large spherical sodalite with a diameter of 5–10 μm and crystal dendritic cancrinite. Dendritic cancrinite was generated by recrystallisation of amorphous Al/Si oxides with spherical sodalite as the intermediate. With the addition of ascorbic acid, magnetisation of the weakly magnetised sludge increased from 0.11 emu g⁻¹ to 3.6 emu g⁻¹ and 14.8 emu/g by raising the NaOH concentration from 2 M to 4 M and 6 M. The magnetic property was related to the magnetite generated from the reduction of ferrihydrite and hematite in the sludge by the added ascorbic acid. Dendritic cancrinite exhibited an optimal surface site concentration of 0.31 mmol g⁻¹ and desirable adsorption capacity of tetracycline (TC) (482.6 mg g⁻¹), which were twice those of spherical sodalite prepared with 4 M NaOH. This study not only highlights the resource recovery of wastewater treatment sludge for MP preparation but also presents a new and effective adsorbent for treatment of TC-containing wastewater.

Water treatment sludge was directly converted into magnetic spherical sodalite and dendritic cancrinite particles, separately. These particles were efficient in tetracycline adsorption.

Nanopore enriched hollow carbon nitride nanospheres with extremely high visible-light photocatalytic activity in the degradation of aqueous contaminants of emerging concern

Nanopore enriched hollow carbon nitride nanospheres exhibit extremely high visible-light photocatalytic activity in the degradation of aqueous contaminants of emerging concern.