Effect of TiO2/Fe2O3 nanopowder synthesis method on visible light photocatalytic degradation of reactive blue dye

Water pollution and scarcity of clean water are major issues of concern globally. In this study, titanium dioxide (TiO2) photocatalyst doped with ferric oxide (Fe2O3) was used to degrade reactive blue dye (171) using sunlight irradiation. Two approaches were employed to synthesize the photocatalyst: synthesis of ferric oxide and titanium precursor through ultrasonic-assisted sol-gel method and using iron (III) nitrate nonahydrate with commercial titanium dioxide. The photocatalysts were characterized using FTIR Spectroscopy, SEM, XRD analyses, and UVDRS to determine their chemical composition, morphology, crystallinity, and light absorption, respectively. The effect of contaminant concentration (1-3 ppm), solution pH and photocatalyst type on the degradation efficiency was studied. Doping enabled visible light absorption as confirmed by the UVDRS analysis. Solar photocatalytic degradation resulted in complete (100 % removal) of the dye within 2 h under solar irradiation for all concentrations of the dye studied. Furthermore, the photocatalysts exhibited superior performance in both neutral and acidic solutions compared to basic ones. After four cycles, the dye removal efficiency has decreased by less than 15 % for all the photocatalysts confirming the significant activity and high stability of the nanocomposite. The increased dye photodegradation efficacy of Fe2O3 doped TiO2 under sunlight irradiation is attributed to the narrowing of the photocatalyst's bandgap from 3.76 eV (in pure TiO2) to 2.83 eV. This narrowing of the bandgap enhances the absorption of visible light from sunlight, thus making this photocatalyst effective under sunlight and eliminating the use of electricity which is a requirement for ultraviolet photocatalysis.

A meta-analysis of ferric carboxymaltose versus other intravenous iron preparations for the management of iron deficiency anemia during pregnancy

Objective

We conducted a meta-analysis of randomized clinical trials evaluating the clinical effects of ferric carboxymaltose therapy compared to other intravenous iron in improving hemoglobin and serum ferritin in pregnant women. We also assessed the safety of ferric carboxymaltose vs. other intravenous iron.

Data source

EMBASE, PubMed, and Web of Science were searched for trials related to ferric carboxymaltose in pregnant women, published between 2005 and 2021. We also reviewed articles from google scholar. The keywords "ferric carboxymaltose," "FCM," "intravenous," "randomized," "pregnancy," "quality of life," and "neonatal outcomes" were used to search the literature. The search was limited to pregnant women.

Selection of studies

Studies related to ferric carboxymaltose in pregnancy were scanned. Observational studies, review articles, and case reports were excluded. Randomized studies in pregnant women involving ferric carboxymaltose and other intravenous iron formulations were shortlisted. Of 256 studies, nine randomized control trials were selected.

Data collection

Two reviewers independently extracted data from nine selected trials.

Data synthesis

The final effect size for increase in hemoglobin after treatment was significant for ferric carboxymaltose vs. iron sucrose/iron polymaltose (standard mean difference 0.89g/dl [95% confidence interval 0.27,1.51]). The final effect size for the increase in ferritin after treatment was more for ferric carboxymaltose vs. iron sucrose/iron polymaltose (standard mean difference 22.53µg/L [-7.26, 52.33]). No serious adverse events were reported with ferric carboxymaltose or other intravenous iron.

Conclusion

Ferric carboxymaltose demonstrated better efficacy than other intravenous iron in increasing hemoglobin and ferritin levels in treating iron deficiency anemia in pregnant women.

Multi-omics analysis reveals the collaboration and metabolisms of the anammox consortia driven by soluble/non-soluble Fe(III) as the sole iron element

Iron is recognized as a physiological requirement for anammox bacteria (AnAOB), with Fe(II) considered to be the most effective form. However, Fe(III), instead of Fe(II) is the common iron form in natural and artificial ecosystems. In this study, the nitrogen removal performance and metabolic mechanisms in anammox consortia with soluble and non-soluble Fe(III) as the sole iron element were investigated. After the 150-day operation, the soluble (FeCl3) and insoluble (Fe2O3) Fe(III)-fed anammox systems reached nitrogen removal rates of 71.84 ± 0.80% and 50.20 ± 0.98%, respectively. AnAOB could survive with soluble (FeCl3) or insoluble (Fe2O3) Fe(III) as the sole iron element, reaching relative abundances of 18.49% and 13.16%, respectively. The results show that the formation of anammox core consortia can enable AnAOB's survival to adverse external conditions of Fe(II) deficiency. Metagenomic and metatranscriptomic analysis reveal that Ca. Kuenenia can only uptake Fe(II) into the cell for metabolisms either independently through the extracellular electron transfer or with the cross-feeding of symbiotic microbes. This study provides insight into the utilization and metabolic mechanisms of Fe(III) in Ca. Kuenenia-dominated consortia, and deepens the understanding of anammox core consortia in the nitrogen, carbon, and iron cycling, further promoting the practical applications of anammox processes.

Anaerobic bioreduction of elemental sulfur improves bioavailability of Fe (III) oxides for bioremediation

Fe(III) oxides are ubiquitous electron acceptors for anaerobic bioremediation, although their bioavailability was limited due to the passivation of secondary mineralization products. Here we found the solid S⁰ can be added to improve their bioavailability. Using lepidocrocite (γ-FeOOH), acetate and Geobacter sulfurreducens PCA as representatives of Fe(III) oxides, intermediate of pollutant degradation and microbes, a 6 times higher amount of FeOOH reduction in the presence of S⁰ was observed with a time needed for S⁰ reduction shortened by half. The bioreduction of S⁰ activated the reduction of FeOOH, while the product (conductive FeS) may have bridged electron transfer across the cell membrane and periplasm. The proportion of excessive Fe(II) produced from Fe(III) was quantified as a direct bioreduction (26 %), with an abiotic FeOOH reduction to FeS (20 %) and an FeS-conducted FeOOH bioreduction (54 %), which highlight the key role of gradually formed FeS from S⁰ in the bioreduction of FeOOH. Our results showed that S⁰ can be an effective additive for the bioremediation of environments with abundant Fe(III) oxides, which has broader implications for elemental biogeochemical cycling.

Improving methane mitigating functionality of blast furnace slag by adding electron acceptor

Blast furnace slag (BFS), a byproduct of iron-producing process, has been applied as silicate fertilizer in rice paddy. Silicate fertilizer contains lime and silicate as main components and iron and manganese as electron acceptors. This amendment improves soil productivity and mitigates methane (CH₄) emissions. However, its suppression effect was limited to <20 % at a field level, and its functionality needs improvement to encourage recycling. We hypothesized that the effect of silicate fertilizer on suppressing CH₄ emission might improve by increasing electron acceptor concentration. To investigate the feasibility of electron acceptor added silicate fertilizer on increasing CH₄ flux suppression, four byproducts of the iron-production process (basic oxygen slag-BOF, ferromanganese slag-FerroMn, iron rust, and Kambara reactor slag-KR) were selected and compared through soil incubation test. Iron rust effectively suppressed CH₄ production by 67 %, which is comparable with a 15-30 % reduction of others. To find the optimum mixing ratio of iron rust, it was mixed to BFS with the rate of 0-5 % (wt wt^-1), and their effect on CH₄ flux was compared. The 3 % mixing ratio highly increased the BFS functionality on suppressing CH₄ production. To confirm the field adaptability of the improved BFS, three types of silicate fertilizer (mixing iron rust with the ratios of 0, 2.5, and 5 %) were applied with the recommendation level (1.5 Mg ha^-1) before rice transplanting. Seasonal CH₄ flux was significantly decreased by the original silicate fertilizer (BFS₀) application to 20 % over control. This effectiveness was enhanced by adding 2.5 % iron rust but thereafter, not more increased. Silicate fertilization (BFS₀) significantly increased rice grain productivity by 9 % over control, and the improved silicate fertilizer (BFS_{2.5 & 5.0}) more highly increased by 13 %. In conclusion, the BFS's functionality to increase rice productivity and suppress CH₄ emission could be improved by adding an effective electron acceptor such as Fe₂O₃.

Emission of volatile sulphur compounds during swine manure composting: Source identification, odour mitigation and assessment

This study aimed to identify the sources of volatile sulphur compounds (VSCs) and evaluate their mitigation by ferric oxide (Fe₂O₃) during swine manure composting. Four chemicals, including l-cysteine, l-methionine, sodium sulphite, and sodium sulphate, were further added to simulate organic and inorganic sulphur-containing substances in swine manure to track VSC sources during composting. Results show that sulphur simulants induced the emission of six common VSCs, including methyl sulphide (Me₂S), dimethyl sulphide (Me₂SS), carbonyl sulphide (COS), carbon disulphide (CS₂), methyl mercaptan (MeSH), and ethyl mercaptan (EtSH), during swine manure composting. Of them, COS, CS₂, MeSH and Me₂SS were predominantly contributed by the biodegradation of methionine and cysteine, while Me₂S and EtSH were dominated by the reduction of sulphite and sulphate. Further Fe₂O₃ addition at 1.5 % of total wet weight of composting materials immobilized elemental sulphur and inhibited sulphate reduction to reduce the emission of VSCs by 46.7-80.9 %. Furthermore, odour assessment indicated that adding Fe₂O₃ into composting piles significantly reduced the odour intensity level to below 4, the odour value of VSCs by 47.1-81.3 %, and thus the non-carcinogenic risk by 68.4 %.

Cadmium removal by FeOOH nanoparticles accommodated in biochar: Effect of the negatively charged functional groups in host

Metallic oxide nanoparticles (NPs) anchored in biochar provide a promising measure forward into the scaled-up application of these NPs in water treatment, and reducing the size of the dwelled NPs is expected to boost the adsorption performance of biochar-based composites because of the size and surface effect. Nevertheless, it is still of great challenge to regulate the size of the impregnated NPs due to their intrinsic self-agglomeration caused by high surface energy. In this study, we fabricated the charged biochar (C-BC) bearing high-density negatively charged groups (i.e., carboxyl and hydroxyl groups) via HNO₃ oxidization to load the model metal oxide FeOOH NPs. The average sizes of anchored FeOOH NPs were ultrasmall, ranging from 19.9 ± 1.5 to 3.1 ± 0.5 nm, and decreased with the increased amount of carboxyl and hydroxyl groups in C-BC. Whether in batch adsorption or fixed-bed column setting, adsorption of Cd(II) onto the as-made composites was greatly enhanced by carboxyl and hydroxyl groups in carrier. The normalized adsorption capacities of Cd(II) by ferric mass of the loaded FeOOH were 499.9-724.9 mg/g-Fe, approximately 18.6-27.1 and 2.51-3.64 folds over the bulky FeOOH and FeOOH-impregnated biochar. Our study results should provide a significant reference on how to acquire highly efficient biochar-based composites for water decontamination.

Iron-activated persulfate oxidation degrades aqueous Perfluorooctanoic acid (PFOA) at ambient temperature

Perfluorooctanoic acid (PFOA, C₈HF₁₅O₂) is an industrial surfactant that is highly resistant to natural breakdown processes such as those mediated by heat, hydrolysis, photolysis, and biodegradation. Many efforts have been developed to breakdown PFOA to less harmful species due to its widespread human exposure and potential toxicity. However, these methods require high temperature or specialized equipment with serious disadvantages of high energy cost for long-term use. We investigated the effectiveness of PFOA degradation by ferrous iron-activated persulfate oxidation (IAPO) under various aqueous geochemical conditions. Approximately 64% of PFOA (initial concentration = 1.64 μmol L^-1) was degraded after 4 h under illuminated anoxic conditions at ambient temperature. This degradation rate and magnitude support the potential use of IAPO as a novel inexpensive and environmentally friendly method to remediate PFOA in soil and groundwater.

Improvising the efficiency of single-sloped solar still using thermally conductive nano-ferric oxide

The world is facing a severe shortage of freshwater, and so we are in urge to fetch new technologies to resolve water scarcity. To desalinate saline water, the single-sloped solar still (SSSS) has proven to be a viable option with much affordability. This research work concentrates on the usage of nanomaterial on the absorbent layer to improve the thermal conductivity of the basin area and thus the distillate produced per hour. The micro-coated and nano-Fe₂O₃ particles were employed and analyzed. The experiment proved that the implementation of this idea had a better productivity rate. The nanoparticles and microparticles were added at weight proportions of 10%. The experiment was conducted on two consecutive days. On the first day, the saline water was maintained at 0.5 cm depth, while on the next day, the saline water level was maintained at 1 cm. The cumulative yield for micro absorbent layer solar still (MALSS) was 3.23 kg/m² and nanoabsorbent layer solar still (NALSS) was 4.39 kg/m².

Novel nanocarrier of miconazole based on chitosan-coated iron oxide nanoparticles as a nanotherapy to fight Candida biofilms

Overexposure of microorganisms to conventional drugs has led to resistant species that require new treatment strategies. This study prepared and characterized a nanocarrier of miconazole (MCZ) based on iron oxide nanoparticles (IONPs) functionalized with chitosan (CS), and tested its antifungal activity against biofilms of Candida albicans and Candida glabrata. IONPs-CS-MCZ nanocarrier was prepared by loading MCZ on CS-covered IONPs and characterized by physicochemical methods. Minimum inhibitory concentration (MIC) of the nanocarrier was determined by the microdilution method. Biofilms were developed (48 h) in microtiter plates and treated with MCZ-carrying nanocarrier at 31.2 and 78 μg/mL, in both the presence and absence of an external magnetic field (EMF). Biofilms were evaluated by total biomass, metabolic activity, cultivable cells (CFU), extracellular matrix components, scanning electron microscopy and confocal microscopy. Data were analyzed by two-way ANOVA and Holm-Sidak test (p < 0.05). A nanocarrier with diameter lower than 50 nm was obtained, presenting MIC values lower than those found for MCZ, and showing synergism for C. albicans and indifference for C. glabrata (fractional inhibitory concentration indexes of <0.12 and <0.53, respectively). IONPs-CS-MCZ did not affect total biomass and extracellular matrix. IONPs-CS-MCZ containing 78 μg/mL MCZ showed a superior antibiofilm effect to MCZ in reducing CFU and metabolism for single biofilms of C. albicans and dual-species biofilms. The EMF did not improve the nanocarrier effects. Microscopy confirmed the antibiofilm effect of the nanocarrier. In conclusion, IONPs-CS-MCZ was more effective than MCZ mainly against C. albicans planktonic cells and number of CFU and metabolism of the biofilms.

Ferric oxide: A favorable additive to balance mechanical strength and biological activity of silicocarnotite bioceramic

Ideal materials for bone regeneration should have not only a good bioactivity, but also a good mechanical strength to provide an initial support for new bone formation. How to get a balance between high mechanical property and good bioactivity is a challenging issue for bone regeneration materials. In the present work, a biocompatible additive Fe₂O₃ was selected to optimize the comprehensive properties of a novel calcium phosphate silicate (CPS) ceramic using a mechanical mixing method. The effects of Fe₂O₃ content on microstructure, bending strength, apatite formation ability and cytocompatibility of Fe-CPS bioceramics were investigated and the related mechanism was also discussed. The obtained Fe-CPS bioceramics showed enhanced mechanical and favorable bioactivity performances. Especially, the Fe-CPS bioceramic with 1.5 wt% Fe₂O₃ sintered at 1250 °C presented the highest bending strength of 91.9 MPa. While, Fe-CPS bioceramics still exhibited a good ability on apatite formation in simulated body fluid (SBF), and cytocompatibility test revealed that Fe-CPS bioceramics were favorable for cell adhesion and proliferation. All the results indicated that Fe-CPS bioceramics are promising candidate materials for bone regeneration at load bearing applications.

Phytoremediation performance of floating treatment wetlands with pelletized mine water sludge for synthetic greywater treatment

PURPOSE

Buckets containing floating reed (Phragmites australis) simulated floating treatment wetlands (FTWs) and were used to improve the remediation performance of synthetic greywater (SGW). The aim of the study was to investigate the behaviour of FTWs for treatment of key contaminants within artificial greywater.

METHODS

Pelletized ochre based on acid mine water sludge was introduced to selected FTWs, because of its capability in sequestration phosphorus and other trace elements. The impact of the following four operational variables were tested in the experimental set-ups of the FTWs (four replicates each): pollutant strength (high- (HC) and low- (LC) concentrations), treatment time (2- or 7-days of hydraulic retention time (HRT)), presence or absence of macrophytes (P. australis) and cement-ochre pellets.

RESULTS

The results showed that 5 - day biochemical oxygen demand (BOD) and chemical oxygen demands (COD) were significantly (p < 0.05) reduced in all wetlands. Nitrate-nitrogen (NO₃-N) concentrations were significantly (p < 0.05) higher, and those measurements for PO₄-P were significantly (p < 0.05) lower than the corresponding ones determined for the influent. The existence of ochre pellets with P. australis significantly (p < 0.05) decreased B, Cd, Cr, Cu, Mg, Ni and Zn concentrations, but increased Al, Ca, Fe and K concentrations in the effluent, with the exception of sodium (Na).

CONCLUSIONS

The FTW performances can be improved by utilising ochre-cement pellets to increase the pH of greywater. The presence of P. australis acts as a buffer to neutralise the pH of SGW. Rhizomes and biofilms mitigate increases in turbidity, TSS and colour values.

Bacteriostatic Potency of Fe2O3 Against Enterococcus faecalis in Synergy with Antibiotics by DDST Method

BACKGROUND

In this study, bacteriostatic potency of the Iron oxide nanoparticles against Enterococcus faecalis (E. faecalis) (a clinical sample and the ATCC11700 strain) was investigated.

METHODS

Nanoparticles' bacteriostatic concentration was determined and used to appraise the characteristics of the Iron Oxide (Fe₂O₃) against the isolates. Antimicrobial examinations with 10⁸ cfu.ml ^-1 were performed at the baseline. Due to evaluation level of potency, after performing Minimum Inhibitory Concentration (MIC), the assessment of death kinetic and susceptibility constant of nanoparticles was done by suspension at two MICs in 0 to 360 min treatment time.

RESULTS

Fe₂O₃ nanoparticles in size range of 10-50 nm demonstrated the most effective susceptibility reaction against E. faecalis and ATCC11700 strain in Z=78.125 ml/μg ^-1 and 39.0625 ml/μg ^-1, respectively. The kinetic reaction of E. faecalis against Fe₂O₃ suspension was supposed to be decreased through the elapse of treatment time, whereas increased concentration was along with bacteria growth after a certain time. So, the efficient concentration of nanoparticles was applied with semi-sensitive and antibiotic resistant for both strains. However, synergism of Fe₂O₃ nanoparticles with Ceftazidime and Clindamycin revealed a higher susceptibility compared with Fe₂O₃nanoparticles alone against E. faecalis.

CONCLUSION

The experimental results reveal that Fe₂O₃ has a strong antimicrobial effect at a certain concentration over the time so could potentially be used for bacterial inhibition and this feature will be strengthened in combination with antibiotics.

Photocorrosion resistant Ag2CO3@Fe2O3/TiO2-NT nanocomposite for efficient visible light photocatalytic degradation activities

Ternary nanocomposite Ag₂CO₃@Fe₂O₃/TiO₂-NT (AFT), compared with binary Fe₂O₃/TiO₂-NT (FTNT) and TiO₂ nanotube (TNT), showed remarkably enhanced performance for catalytic photodegradation of phenol compounds in the presence of solar irradiation. AFT nanocomposite performed high degradation efficiency (96.5%) and high degree of sustainability. The unique catalytic properties of the nanocomposite such as synergetic light absorption, efficient charge separation-transfer and resistance toward photocorrosion suggested three possible alternative mechanisms for transferring photogenerated electrons. Ag₂CO₃@Fe₂O₃/TiO₂-NT nanocomposite may have a potential application for the industrial treatment of wastewater containing toxic organic contamination.

Comparison of the Effects of Iron Oxide, as a New Form of Iron Supplement, and Ferrous Sulfate on the Blood Levels of Iron and Total Iron-Binding Globulin in the Rabbit

Iron oxide is an important biological agent that has a key role in medical processes; however, the mechanism whereby it provides iron for human and animal cells and its biological uses remains unclear. We aimed to evaluate the effects of oral iron oxide on serum iron status and compare the results with those of iron sulfate as a reference salt. Fifteen adult rabbits were divided into 3 groups of 5 each: control group, iron sulfate group, and iron oxide group. The groups received doses of 3.3, 10, and 33 mg/kg in 3 experiments. Venous blood samples were obtained just before the oral administration of iron sulfate and iron oxide (3.3 mg/kg). More blood samples were taken 3 times at the time points of 1, 6, and 12 hours after the administration of the solutions. Serum was separated for the measurement of iron (Fe) and total iron-binding globulin (TIBG) with routine methods. One week later, the same experiment was repeated with 10 mg/kg of iron sulfate and iron oxide; and 1 week later after the second experiment, again the same experiment was repeated with 33 mg/kg of iron sulfate and iron oxide. The results showed that 33 mg/kg of iron sulfate 1 hour after treatment caused a significant difference in the Fe and TIBG levels between all the groups (P=0.014 for Fe and P=0.027 for TIBG). Our data showed that the absorption of iron oxide was similar to that of ferrous sulfate and in high doses was as useful as iron supplement.