Addition Of H2O2 Research Articles

Synergistic adsorption-Fenton degradation of organic pollutants by MIL-88B/montmorillonite and cellulose nanocrystals functionalized gelatin composite aerogels

In this work, MIL-88B loaded montmorillonite (MMT) and cellulose nanocrystals (CNC) were incorporated into gelatin (G) aerogel to yield a multifunctional and reinforced bio-aerogel, named as MMCG aerogel, for removing organic pollutants by synergistic adsorption and Fenton degradation. As expected, the MMCG aerogels exhibited highly efficient adsorption capacity for charged pollutants. The adsorption process of methyl blue (MB) followed well with Langmuir isotherm, while tetracycline hydrochloride (TCH) and methylene blue (MEB) could be better fitted by Freundlich isotherm. The adsorption kinetics were accurately described by the pseudo-second-order kinetic model. Thermodynamic experiments revealed that the adsorption process was endothermic and spontaneous. The maximum adsorption capacities for MB, MEB and TCH were 1494.47 mg/g, 952.26 mg/g and 701.82 mg/g, respectively. Electrostatic interactions, hydrogen bonds and π-π interactions may be responsible for the adsorption mechanism. Most importantly, it exhibited better removal performance for all organic contaminants with or without charged states by triggering the Fenton reaction with the addition of H2O2. For the non-adsorbed bisphenol A (BPA) with uncharged state, the removal efficiency after Fenton degradation significantly increased from 4.73 % to 86.13 %. Additionally, it had excellent recyclability. Therefore, the MMCG aerogel could be recognized as a promising material for wastewater treatment.

Enhancement of graphitic carbon nitride (g‐C3N4) assisted photodegradation of Rhodamine B under visible light

AbstractIn the current work, the g‐C3N4 photocatalyst was produced by thermal polycondensation of melamine. The Characterization techniques XRD, SEM, FTIR, UV‐DRS, PL, and BET were investigated to find out inherent properties. The PL spectra of the g‐C3N4 photocatalyst showed good absorbance in visible regions for faster degradation of Rhodamine B (RhdB). The synthesized g‐C3N4 photocatalyst is employed for decolorization and demineralization of RhdB about 73 % and 80 % in 105 min and 480 min under visible light. Further, the addition of H2O2 and H2SO4 to RhdB solution in the presence of g‐C3N4 showed enhanced results when compared to g‐C3N4 alone. Moreover, it reduces the time for the removal of RhdB. Simultaneously impeding shift of the maximum absorption peak of RhdB represents alteration of the degradation mechanism. Under alike conditions of photodegradation, after the addition of H2O2 and H2SO4 to the dye solution. The removal of RhdB is enhanced to 98 % and 95 % in 40 min, and 60 min for 5 mg/l and 10 mg/l respectively for H2O2. Further, the addition of H2SO4 enhances efficiency up to 87 %, and 95 % in 50 min, and 80 min respectively for 5 mg/l and 10 mg/l. The overall H2O2 addition showed better efficiency and better rate constants.

Synthesis of CoWO4/g-C3N4 Z-scheme heterojunction for the efficient photodegradation of diazinon with the addition of H2O2

Pesticides are on the list of substances that are routinely monitored by agencies and organizations in various natural environments and habitats. Diazinon (DZN) is the active ingredient in more than 20 agricultural pesticides, it causes the most damage and has been prohibited in many countries around the world. The final product CoWO4/g-C3N4 Z-scheme heterojunction was successfully synthesized in this work, where CoWO4 nanoparticles were deposited on the surface of g-C3N4. CoWO4/g-C3N4 structure allowed for the efficient separation of photo-generated electron-hole pairs, with electrons at the CoWO4 CB migrating to the g-C3N4 VB and preserving the electrons at the g-C3N4 CB and holes in the CoWO4 VB. The photodegradation efficiency of DZN using CoWO4/g-C3N4 Z-scheme heterojunction was investigated, as compared with its precursors, such as CoWO4, and g-C3N4. CoWO4/g-C3N4 Z-scheme heterojunction demonstrated the highest degradation capacity for DZN removal. Based on the results, the photocatalysis of the CoWO4/g-C3N4 Z-scheme heterojunction can be recycled for the effective removal of DZN by simple washing after three runs, proving the heterojunction’s stability and suggesting CoWO4 as a promising material for the removal of DZN from contaminated water sources.

Fabrication of ZnO/Ag and ZnO/Fe nanoparticles with immobilised peroxidase as a biocatalyst for photodegradation of ibuprofen

This paper presents the preparation of a photocatalyst based on ZnO nanoparticles modified with silver and iron ions and peroxidase (ZnO/Ag/POX NPs and ZnO/Fe/POX NPs). The materials were characterised using XRD, AAS, TEM, FTIR, and UV–Vis analyses. Metal ion sorption analysis revealed that Ag and Fe ions were successfully adsorbed on the ZnO surface, reaching sorption capacities of 13.39 mg/g and 41.47 mg/g, respectively. After peroxidase immobilisation, ZnO/Ag/POX NPs and ZnO/Fe/POX NPs were obtained, presenting peroxidase activities of 291.34 and 223.78 U/g, respectively. Based on the ibuprofen decomposition study, the effectiveness of the photocatalysts was confirmed. After 120 min, the decomposition efficiency of ibuprofen with an initial concentration of 20 mg/L in the presence of H2O2 additive was 78 and 86% for ZnO/Ag/POX NPs and ZnO/Fe/POX NPs, respectively. ZnO/Fe/POX NPs showed the highest activity, which increased by 40% after the addition of H2O2. It is suggested that the high efficiency of the material is due to two separate processes taking place: the Fenton reaction and the decomposition of H2O2 by peroxidase.

Analysis of Microcystis aeruginosa physiology by spectral flow cytometry: Impact of chemical and light exposure.

M. aeruginosa fluorescent changes were observed using a Cytek Aurora spectral flow cytometer that contains 5 lasers and 64 narrow band detectors located between 365 and 829 nm. Cyanobacteria were treated with different concentrations of H2O2 and then monitored after exposure between 1 and 8 days. The red fluorescence emission derived from the excitation of cyanobacteria with a yellow green laser (550 nm) was measured in the 652-669 nm detector while green fluorescence from excitation with a violet laser (405 nm) was measured in the 532-550 nm detector. The changes in these parameters were measured after the addition of H2O2. There was an initial increase in red fluorescence intensity at 24 hours. This was followed by a daily decrease in red fluorescence intensity. In contrast, green fluorescence increased at 24 hours and remained higher than the control for the duration of the 8-day study. A similar fluorescence intensity effect as H2O2 on M. aeruginosa fluorescence emissions was observed after exposure to acetylacetone, diuron (DCMU), peracetic acid, and tryptoline. Minimal growth was also observed in H2O2 treated cyanobacteria during exposure of H2O2 for 24 days. In another experiment, H2O2-treated cyanobacteria were exposed to high-intensity blue (14 mW) and UV (1 mW) lights to assess the effects of light stress on fluorescence emissions. The combination of blue and UV light with H2O2 had a synergistic effect on M. aeruginosa that induced greater fluorescent differences between control and treated samples than exposure to either stimulus individually. These experiments suggest that the early increase in red and green fluorescence may be due to an inhibition in the ability of photosynthesis to process photons. Further research into the mechanisms driving these increases in fluorescence is necessary.

Thiol-Based Modification of MarR Protein VnrR Regulates Resistance Toward Nitrofuran in Vibrio cholerae By Promoting the Expression of a Novel Nitroreductase VnrA and of NO-Detoxifying Enzyme HmpA.

Aims: Epidemiological investigations have indicated low resistance toward nitrofuran in clinical isolates, suggesting its potential application in the treatment of multidrug-resistant bacteria. Therefore, it is valuable to explore the mechanism of bacterial resistance to nitrofuran. Results: Through phenotypic screening of ten multiple antibiotic resistance regulator (MarR) proteins in Vibrio cholerae, we discovered that the regulator VnrR (VCA1058) plays a crucial role in defending against nitrofuran, specifically furazolidone (FZ). Our findings demonstrate that VnrR responds to FZ metabolites, such as hydroxylamine, methylglyoxal, hydrogen peroxide (H2O2), β-hydroxyethylhydrazine. Notably, VnrR exhibits reversible responses to the addition of H2O2 through three cysteine residues (Cys180, Cys223, Cys247), leading to the derepression of its upstream gene, vnrA (vca1057). Gene vnrA encodes a novel nitroreductase, which directly contributes to the degradation of FZ. Our study reveals that V. cholerae metabolizes FZ via the vnrR-vnrA system and achieves resistance to FZ with the assistance of the classical reactive oxygen/nitrogen species scavenging pathway. Innovation and Conclusion: This study represents a significant advancement in understanding the antibiotic resistance mechanisms of V. cholerae and other pathogens. Our findings demonstrate that the MarR family regulator, VnrR, responds to the FZ metabolite H2O2, facilitating the degradation and detoxification of this antibiotic in a thiol-dependent manner. These insights not only enrich our knowledge of antibiotic resistance but also provide new perspectives for the control and prevention of multidrug-resistant bacteria.

Optimization, synthesis, and properties of foamed graphene reinforced slag/fly ash-based geopolymer composites

To obtain hybrid foams with higher porosity and better performance, a novel lightweight foamed slag/fly ash-based graphene/geopolymer composite was prepared using a foaming method with graphene nanoplatelets (GNPs). The synergistic effects of the foaming agent (H2O2) and GNPs content on the phase structure, pore distribution, and mechanical and thermal properties of the obtained foamed graphene/geopolymer composites were investigated. The GNPs were well-dispersed in the final foamed composites. The non-crystalline structure of the foamed composites was maintained with the addition of GNPs. The mean pore size of the foamed samples obtained by adding 1.25 wt% GNPs and 3 wt% H2O2 to the geopolymer was ~340 μm. The total porosity of the samples was 13.1–76.2 %. The total porosity increased as the H2O2 ratio increased and declined with the addition of the GNPs because greater GNPs addition increased the solid content of the slurry, which affected the foaming process of the geopolymer matrix. The compressive strength of the 28-day aged foamed samples increased relative to that of the 7-day samples, attributed to the geopolymerization of the matrix, pull-out, and crack deflection of the GNPs. The thermal conductivity of samples decreased with the H2O2 addition, and achieved the thermal conductivity of 0.191 W/(m·K) with the addition of 1.250 wt% GNPs and 5 wt% H2O2. These samples have potential applications in construction, thermal insulation, etc.

The degradation of 1,4 acetaminophen by electrocatalytic oxidation process and investigation the by-products of the system

The study was aimed at using Ti/IrO2-RuO2 electrocatalytic electrodes for the purpose of removing 1,4-acetaminophen from a solution. The electrooxidation process's efficiency was studied by controlling various parameters such as pH (3−11), current density (100–1000 A.m-2), electrolyte type (NaCl, Na2SO4, KCl), and conductivity (1.5–10 mS.cm-1). Additionally, H2O2 addition (100–1000 µL), and acetaminophen concentration (25–100 ppm) were also studied. In addition, it was found that when the initial concentrations were increased from 25 ppm to 100 ppm, there was a corresponding increase in the removal efficiencies, which ranged from 27% to 36% at a current density of 350 A.m-2 and a conductivity of 3.5 mS.cm-1 for a period of 90 min. The removal efficiency increased from 30% to 42% when 0.5 mL of 30% H2O2 was added to the initial concentration of 50 ppm. The presence of chlorine ions in a solution has been demonstrated to result in the formation of oxidation products. This result has enabled researchers to investigate the toxic and disinfecting properties of the solution. The LC-MS spectra analysis revealed the formation of intermediate degradation products. The identification of these metabolites enabled the suggestion of their structure and degradation mechanism.

Low acrosin activity is associated with decreased Spam1/acrosin expression and GSH deficiency-caused premature acrosome release of human sperm cells.

Low acrosin activity (LAA) is associated with sperm function anomaly and poor outcomes of in vitro fertilization. In this study, we confirm that 993 semen samples with LAA had a reduced sperm motility and low in vitro fertilization rate in comparison with 1332 normal controls (NC). Proteomic comparison between 11 LAA and 11 NC sperm samples identified 35 upregulated and 99 downregulated proteins in the LAA group. Indeed, proteomic data showed that acrosome enzymes Spam1 and Acrosin were among the downregulated proteins in the LAA group, which was validated by quantitative PCR and immunefluorescent staining of sperm cells. The KEEG pathway analysis revealed a deficiency of GSH and Gln biosynthesis in LAA sperm cells. Immunofluorescent staining of sperms and quantitative PCR verified downregulation of GLUL and GCLC, the key enzymes for GSH and Gln biosynthesis. Moreover, the results of ELISA assay confirmed low levels of GSH and Gln in LAA sperm cells. Mechanistic studies showed that addition of 10mM H2O2 to semen samples led to a significant reduction of acrosin activity and sperm motility, most possibly by triggering premature acrosome release. In contrast, the presence of 20mM GSH blocked the oxidative effects of H2O2. Since GSH counteracts the oxidative stress and Gln participates in TCA cycling, their deficiency may affect the redox balance as well as energy production of sperm cells. These findings shed new light on the pathological mechanisms of infertility associated with LAA. Male infertility patients could benefit from GSH supplement by improvement of acrosin activity and other sperm functions.

Study on synergistic catalytic degradation of wastewater containing polyacrylamide catalyzed by low-temperature plasma-H2O2.

The degradation behavior of polyacrylamide (PAM) solution by low-temperature plasma was investigated, and the effect of some factors that might affect the degradation process was further examined. The PAM solution was treated with low-temperature plasma generated by dielectric barrier discharge (DBD) combined with H2O2 and a Mn + Cu/AC composite catalyst. The optimal conditions for the oxidation degradation of a PAM solution using low-temperature plasma-H2O2-Mn + Cu/AC were determined as follows: initial concentration of 1000mg/L, discharge voltage of 18kV, H2O2 addition of 2%, and catalyst addition of 810mg. The results indicated that the degradation rate increased with the increase of the catalyst dosage at the same discharge time. The degradation rate of 180min increases from 90 to 97.6% with an increase in voltage from 16 to 18kV, and the molecular weight decreases from 2,720,204.23 to 1,370,815.54. The degradation effect caused by the change of H2O2 addition was considerable compared with other factors. When the discharge time was 180min, the degradation rate increased 26.3% with the increase of 1.6% H2O2 addition. Under the optimal process conditions, the addition of the catalyst resulted in a more rapid initial decrease in the pH value of the solution compared to the system without the catalyst.

Enhanced degradation of metformin using surface-coated vortex diodes

The present work successfully demonstrates, for the first time, complete degradation of metformin using newer surface-coated vortex diode (SCVD) with copper and nickel coating to provide catalytic activity in the conventional hydrodynamic cavitation (HC) for significantly enhanced degradation efficiency. The SCVDs have dual functionality and the efficacy of catalytic cavitation reactors get enhanced using process intensifications of the type H2O2 addition, pH modification, and combined approach of HC+ pH+ H2O2 apart from the advantage of low pressure drop for the vortex flow based cavitation in vortex diode (ΔP of 1 bar). Complete, 100%, degradation of metformin (MTF) was achieved within 5 min with integration of optimized H2O2 dose and exceptionally high synergistic index value over 300, indicating extraordinary synergy for both Cu and Ni-SCVD. Acidic condition promote degradation and a complete degradation with a high 43–48% mineralization was observed using HC+ pH 4+ (1:200) H2O2 with less intermediates formation. The SCVDs reveal remarkable enhancement of ∼9800% in per-pass degradation and 1400–3400% in cavitational yield as compared to conventional cavitation process under similar conditions. The newer SCVDs with catalytic activity can provide more cost-effective solutions for industrial and real-life applications.

Optical Signatures of Phosphorene Chemical Evolvement in Liquid Environment

Phosphorene possesses a unique combination of physical and chemical properties, including tunable direct bandgap, anisotropic electronic and optical properties. However, application of phosphorene is hampered by its fast degradation under ambient conditions. It is believed that H2O and O2 play key roles in the instability of phosphorene, but their exact contributions have not yet been completely understood in experiment. Herein, a technique of probing the mechanism of phosphorene oxidation through the evolvement of its photoluminescence spectra in a liquid suspension is introduced. With the addition of H2O2, the photoluminescence intensity of the suspension surprisingly increases, indicating a passivation effect due to the formation of phosphorene oxide, which is also verified by Raman spectroscopy. In contrast, direct addition of H2O leads to irreversible and rapid degradation as shown by the quenching of photoluminescence. Furthermore, monolayer phosphorene suspension photoluminescence at 2.17 eV is obtained by completely eliminating effects from contaminations, substrate strain, dielectric substrate, and oxidation of samples. Solvent protection in combination with the optical probing method provides an effective approach in investigating the chemistry of active materials like phosphorene. Phosphorene has great potential in the range of sensing applications including high‐resolution H2O2 and humidity sensors.

Oxygen Defect Engineering Promotes Synergy Between Adsorbate Evolution and Single Lattice Oxygen Mechanisms of OER in Transition Metal-Based (oxy)Hydroxide.

The oxygen evolution reaction (OER) activity of transition metal (TM)-based (oxy)hydroxide is dominated by the number and nature of surface active sites, which are generally considered to be TM atoms occupying less than half of surface sites, with most being inactive oxygen atoms. Herein, based on an in situ competing growth strategy of bimetallic ions and OH- ions, a facile one-step method is proposed to modulate oxygen defects in NiFe-layered double hydroxide (NiFe-LDH)/FeOOH heterostructure, which may trigger the single lattice oxygen mechanism (sLOM). Interestingly, by only varying the addition of H2 O2 , one can simultaneously regulate the concentration of oxygen defects, the valence of metal sites, and the ratio of components. The proper oxygen defects promote synergy between the adsorbate evolution mechanism (AEM, metal redox chemistry) and sLOM (oxygen redox chemistry) of OER in NiFe-based (oxy)hydroxide, practically maximizing the use of surface TM and oxygen atoms as active sites. Consequently, the optimal NiFe-LDH/FeOOH heterostructure outperforms the reported non-noble OER catalysts in electrocatalytic activity, with an overpotential of 177mV to deliver a current density of 20mA cm-2 and high stability. The novel strategy exemplifies a facile and versatile approach to designing highly active TM-LDH-based OER electrocatalysts for energy and environmental applications.

BTN3A3 inhibits clear cell renal cell carcinoma progression by regulating the ROS/MAPK pathway via interacting with RPS3A

Butyrophilin subfamily 3 member A3 (BTN3A3) is a member of the immunoglobulin superfamily and functions as a tumor suppressor in multiple cancer types. Our study has revealed that in clear cell renal cell carcinoma (ccRCC), patients who express high levels of BTN3A3 experience longer survival times than those with lower expression. Further, we have observed that BTN3A3 inhibits the proliferation, migration, and invasion of ccRCC cells. Through the utilization of an immunoprecipitation assay followed by mass spectrometry, we have discovered that BTN3A3 binds directly to RPS3A. Knockdown of BTN3A3 led to increased cell proliferation, migration, and invasion. However, this effect was significantly reduced when RPS3A was simultaneously overexpressed. Previous reports have demonstrated that RPS3A positively regulates mitochondrial function and reactive oxygen species (ROS) levels. Our study has shown that overexpression of both BTN3A3 and RPS3A can increase cellular oxygen consumption rate (OCR) and ROS levels. Furthermore, we have observed that the addition of H2O2 can reverse the effects of BTN3A3 knockdown on cell proliferation and migration by increasing the cellular ROS level. ROS play a crucial role in regulating the MAPK pathway and tumor cell growth. To further explore this relationship, we examined RNA-Seq and immunoblotting data and found that BTN3A3 can negatively regulate the degree of activation of the MAPK signaling pathway. This finding suggests that the BTN3A3/RPS3A complex may regulate ccRCC progression by modulating MAPK pathways. Therefore, BTN3A3 could serve as both a prognostic marker and a potential therapeutic target for ccRCC patients.

Properties of a Soluble Lead Flow Battery Recycled with Hydrogen Peroxide

AbstractThe service life of soluble lead flow batteries can be extended by periodic addition of H2O2, especially when it failed. However in first few cycles after H2O2 treatment, its coulombic efficiency is very low. To clarify it, the properties of electrode and electrolyte, and cycle performance have been systematically analyzed. It has been found that the negative/positive electrode reactions have serious overpotentials during early charging due to oxygen, which are produced and dissolved into the electrolyte during H2O2 treatment. With increasing the cycle number, the polarization degree decreases to the normal level of the battery. To solve it, oxygen is removed using argon after H2O2 treatment. The flow cell is normally recovered in the cycling performance. The average coulomb efficiency is 94.5±5.8 % for 500 times. After H2O2 treatment and oxygen removal, it exhibits a good cycling performance at the average coulomb efficiency of 93.9±4.2 % for another 500 times.

Assessment of solar water disinfection enhancement with H2O2 and dissolved oxygen on inactivating different waterborne pathogens

Water scarcity has been growing for the last decades and one feasible solution for water-deprived areas is the storage and treatment of roof-harvested rainwater. Solar disinfection (SODIS) is a proven water treatment procedure, but several drawbacks still need assessing, such as increasing the output volume of treated water, reducing the treatment time and/or increasing the inactivation efficiency performance. In this study, the addition of low concentrations (1–5 mg/L) of H2O2 and/or the increment of dissolved oxygen (DO) has been tested at a pilot plant scale using a solar Compound Parabolic Collector photo-reactor with the aim of enhancing the disinfection efficiency of SODIS. Their performance has been assessed against a consortium of five pathogens normally found in rainwater: E. coli, E. faecalis, S. enteritidis, P. aeruginosa and MS2 bacteriophage. The addition of DO and/or H2O2 to solar photo-inactivation (SP-I) proved to enhance pathogens’ inactivation kinetics. Results have shown that O2 supply affects E. coli, P, aeruginosa and E. faecalis as their kinetic constants increase 1.48, 1.17 and 1.6 times, respectively. On the other hand, H2O2 addition enhances the inactivation of all pathogens. being the most noteworthy MS2 inactivation as > 5 Log Reduction Values (LRV) were reduced for all concentrations between 99% and 95% of the energy required for SP-I. Finally, the combination of both agents is also effective but can only be noted in E. faecalis inactivation, which is better than with only H2O2 addition. The findings obtained in this study show that from the perspective of implementing solar technologies in the field, the addition of DO sparging can be discarded due to a slightly enhanced disinfection performance, while the use of low H2O2 concentrations can be envisaged due to both, the enhancement of the disinfection performance and the competitive cost estimated (0.0025 €/L) in comparison with only SODIS (0.002 €/L).

Human Osteoblasts' Response to Biomaterials for Subchondral Bone Regeneration in Standard and Aggressive Environments.

Osteochondral lesions, when not properly treated, may evolve into osteoarthritis (OA), especially in the elderly population, where altered joint function and quality are usual. To date, a collagen/collagen-magnesium-hydroxyapatite (Col/Col-Mg-HAp) scaffold (OC) has demonstrated good clinical results, although suboptimal subchondral bone regeneration still limits its efficacy. This study was aimed at evaluating the in vitro osteogenic potential of this scaffold, functionalized with two different strategies: the addition of Bone Morphogenetic Protein-2 (BMP-2) and the incorporation of strontium (Sr)-ion-enriched amorphous calcium phosphate (Sr-ACP) granules. Human osteoblasts were seeded on the functionalized scaffolds (OC+BMP-2 and OC+Sr-ACP, compared to OC) under stress conditions reproduced with the addition of H2O2 to the culture system, as well as in normal conditions, and evaluated in terms of morphology, metabolic activity, gene expression, and matrix synthesis. The OC+BMP-2 scaffold supported a better osteoblast morphology and stimulated scaffold colonization, cell activity, and extracellular matrix secretion, especially in the stressed culture environment but also in normal culture conditions, with increased expression of genes related to osteoblast differentiation. In conclusion, the incorporation of BMP-2 into the Col/Col-Mg-HAp scaffold also represents an improvement of the osteochondral scaffold in more challenging conditions, supporting further preclinical studies to optimize it for use in clinical practice.

Optimal extraction of polysaccharides from Stevia rebaudiana roots for protection against hydrogen peroxide-induced oxidative damage in RAW264.7 cells

Stevia rebaudiana boasts a wide range of medical and food applications and contains polysaccharides that exert beneficial effects against oxidative stress. In this study, we optimised the extraction of a polysaccharide (SRRP) from S. rebaudiana roots by employing a Box–Behnken design and response surface methodology. The optimal extraction conditions were as follows: 93.57 min, 71.67 °C, and a water-to-raw material ratio of 21.40 mL/g. Under these conditions, 14.00 ± 0.35% of crude polysaccharide was obtained. Treatment of RAW264.7 cells with SRRP prior to the addition of H2O2, a major contributor to oxidative damage, significantly increased cell viability. In addition, SRRP increased the levels of superoxide dismutase, catalase, and glutathione and reduced the levels of malondialdehyde in RAW264.7 cells. Therefore, SRRP can provide effective protection against H2O2-induced oxidative damage. These findings indicate the potential of SRRP as a natural antioxidant in the food and pharmaceutical industries.

In-situ utilization of EPS improves the directional oxidation ability of Fe(III)/H2O2 and enhances sludge dewaterability

Inefficient sludge dewatering can result in high costs for sludge treatment and disposal, as well as increased pollution of the environment. In this study, we constructed a double oxidation–reduction (Redox) cycle system of Fe(II)/Fe(III) and Fe(II)-extracellular polymeric substance (EPS)/Fe(III)-EPS by utilizing EPS in situ and collaborating with Fe (III) and H2O2 so as to regulate the performance of Fenton oxidation for efficiently enhancing the dewaterability. Results displayed the specific resistance to filtration (SRF) reduced from 34.1 ± 2.4 × 1012 m/kg to 16.2 ± 1.5 × 1012 m/kg with only 0.15 mmol Fe(III)/g VSS and 1.46 mmol H2O2/g VSS. Notably, the formation of relative stable Fe(III)-EPS complex was found under the interval addition of Fe(III) and H2O2. Four types of reactive species (hydroxyl radical (•OH), singlet oxygen (1O2), superoxide radical (O2•-) and Fe(IV)) which could effective destroy EPS structure during conditioning process, were generated after the addition of H2O2. It effectively promoted the transition from intracellular oxidation to extracellular oxidation under Fenton oxidation conditions, which reduced negative effects of cell lysis under excessive oxidation during sludge conditioning. The structure of EPS damaged significantly during the oxidation process, leading to the effective conversion of bound water to free water. Meanwhile, the existence of dissociative Fe(III) promoted the aggregation of sludge flocs, generating large channels or pores for sludge water to discharge, and then improving the dewaterability. Overall, [Fe(III)-EPS]/H2O2 treatment as an efficient sludge conditioning method can provide guidance for sludge dewaterability enhancement in urban sludge treatment and disposal.

Effective removal of arsenite from water using polylactic acid ZIF-8 biocomposite nanofiber

Water purification from As(III)-contaminated groundwater is difficult but highly needed. Herein, a new polylactic acid ZIF-8 biocomposite nanofiber mat (ZIF-8@PLA/NFM) was fabricated using an electrospinning technique for As(III) decontamination. The active component, ZIF-8 nanoparticles, are uniformly embedded in sustainable PLA fibers and can be rapidly contacted by As(III), achieving fast kinetics and high utilization of nanoparticles. The removal experiments show that the ZIF-8@PLA/NFM can effectively remove As(III), especially in combination with H2O2. The 50%-ZIF-8@PLA/NFM with 1 mM H2O2 reduced 1000 μg/L As(III) to less than 10 μg/L in just 5 min through the synergy of oxidation and adsorption. The maximum sorption capacity for As(III) on 50-ZIF-8@PLA/NFM was 11.61 ± 0.99 mg/g, which increased to 39.25 ± 3.84 mg/g with the addition of H2O2. It performed well in the pH range of 4–9. The combination of H2O2 broadened its effective pH operating range (3–10) as well as enhanced interference resistance, enabling deep removal of As(III) across a wide range of water environments. The As(III)-spiked natural water (100 μg/L) could be purified to drinking standard level by ZIF-8@PLA/NFM within 60 min. In combination with H2O2, the removal efficiency was reduced by only 1.5% at the fifth reuse. Macroscopic experiments and microscopic characterization suggest that the adsorption follows the inner-sphere complexes mechanism. The study provides a novel approach for the fabrication of efficient, easy-to-use, and sustainable MOFs-based biocomposite for As(III) decontamination.