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Environmental Science and Pollution... Dec 2018The effect of varying inorganic (chloride, nitrate, sulfate, and phosphate) and organic (represented by humic acid) solutes on the removal of aqueous micropollutant...
The effect of varying inorganic (chloride, nitrate, sulfate, and phosphate) and organic (represented by humic acid) solutes on the removal of aqueous micropollutant bisphenol A (BPA; 8.8 μM; 2 mg/L) with the oxidizing agents hydrogen peroxide (HP; 0.25 mM) and persulfate (PS; 0.25 mM) activated using zero-valent aluminum (ZVA) nanoparticles (1 g/L) was investigated at a pH of 3. In the absence of the solutes, the PS/ZVA treatment system was superior to the HP/ZVA system in terms of BPA removal rates and kinetics. Further, the HP/ZVA process was not affected by nitrate (50 mg/L) addition, whereas chloride (250 mg/L) exhibited no effect on the PS/ZVA process. The negative effect of inorganic anions on BPA removal generally speaking increased with increasing charge in the following order: NO (no inhibition) < Cl (250 mg/L) = SO < PO for HP/ZVA and Cl (250 mg/L; no inhibition) < NO < SO < PO for PS/ZVA. Upon addition of 20 mg/L humic acid representing natural organic matter, BPA removals decreased from 72 and 100% in the absence of solutes to 24 and 57% for HP/ZVA and PS/ZVA treatments, respectively. The solute mixture containing all inorganic and organic solutes together partly suppressed the inhibitory effects of phosphate and humic acid on BPA removals decreasing to 46 and 43% after HP/ZVA and PS/ZVA treatments, respectively. Dissolved organic carbon removals were obtained in the range of 30 and 47% (the HP/ZVA process), as well as 47 and 57% (the PS/ZVA process) for the experiments in the presence of 20 mg/L humic acid and solute mixture, respectively. The relative Vibrio fischeri photoluminescence inhibition decreased particularly for the PS/ZVA treatment system, which exhibited a higher treatment performance than the HP/ZVA treatment system.
Topics: Aliivibrio fischeri; Aluminum; Benzhydryl Compounds; Chlorides; Humic Substances; Hydrogen Peroxide; Kinetics; Models, Chemical; Oxidants; Oxidation-Reduction; Phenols; Solutions; Sulfates; Water; Water Pollutants, Chemical; Water Purification
PubMed: 29322392
DOI: 10.1007/s11356-017-1182-9 -
Water Research Sep 2021Cell-viability of cyanobacteria declines from development to decay stage during a successive bloom. Potassium permanganate (KMnO) has demonstrated to be a superior...
Cell-viability of cyanobacteria declines from development to decay stage during a successive bloom. Potassium permanganate (KMnO) has demonstrated to be a superior pre-oxidant to treat high-viability cyanobacteria compared to other common oxidants (e.g., chlorine), but whether it is feasible to treat low-viability cyanobacteria is unknown. Here, effects of KMnO on membrane integrity, cyanotoxin fate and extracellular organic matters (EOMs) removal of high- and low-viability cyanobacteria were compared. Results showed that cell-viability of cyanobacteria could affect oxidant decay (k), membrane damage (k), and cyanotoxins release (k) and degradation (k) during KMnO oxidation, similar to chlorination. However, unlike chlorination, initial low dosages of KMnO (0.5 and 1 mg L) minimized membrane damage for low-viability cyanobacteria (< 27%), and continuously decrease extracellular cyanotoxins, extracellular organic matters (EOMs), and aromatic compounds to some degrees (P<0.05). High dosages of KMnO (> 2 mg L) caused severe membrane destruction (> 89%) for low-viability cyanobacteria, leading to a fast increase of extracellular cyanotoxins within 1 h. However, total/extracellular cyanotoxins were oxidized to below the safety guideline of 1 μg L after being dosed with sufficient oxidant exposure. EOMs and aromatic compounds were also reduced by 5-18% (P<0.05). Additionally, KMnO-assisted coagulation significantly improved the removal of low-viability cyanobacteria (2-5 fold). Consequently, KMnO could be a promising pre-oxidant to treat low-viability cyanobacteria at decay stage of a successive bloom.
Topics: Chlorine; Cyanobacteria; Halogenation; Oxidants; Oxidation-Reduction; Potassium Permanganate; Water Purification
PubMed: 34246989
DOI: 10.1016/j.watres.2021.117353 -
Environmental Science & Technology Dec 2021Manganese (Mn) oxides are considered as the primary oxidant of trivalent chromium [Cr(III)] in the environment. Microbial activities are responsible for the majority of...
Manganese (Mn) oxides are considered as the primary oxidant of trivalent chromium [Cr(III)] in the environment. Microbial activities are responsible for the majority of Mn oxide formation in nature, thus likely influencing Cr(III) oxidation. Previous studies have been limited to Cr(III) oxidation by bacterial Mn oxides. Herein, we report coupled Mn(II) and Cr(III) oxidation in the presence of three Mn(II)-oxidizing Ascomycete fungi. In contrast to the previously reported inhibitory effect of Cr(III) on bacterial Mn(II) oxidation, varying effects of Cr(III) on fungal Mn(II) oxidation were observed, which may be linked to their Mn(II)-oxidation mechanisms. Under the concentrations of Mn(II) and Cr(III) applied in this study, Cr(III) promoted Mn(II) oxidation if it was mediated by hyphae-associated processes, but inhibited Mn(II) oxidation if it was achieved via extracellular enzymes/metabolites. The Cr(III) oxidation rate and extent were affected by Cr(III) speciation, Cr(VI) removal capacity (i.e., adsorption/reduction) of fungi, and organic content. The morphology and spatial relationship of Mn oxides with fungi varied, depending on fungal species and Cr(III) presence. Our findings highlight the importance of Mn(II)-oxidizing fungi in biogeochemical cycles of Mn and Cr and have significant implications for the origin of geogenic Cr(VI) and stability of reduced chromium in contaminated environments.
Topics: Adsorption; Ascomycota; Bacteria; Chromium; Manganese Compounds; Oxidation-Reduction; Oxides
PubMed: 34825822
DOI: 10.1021/acs.est.1c05341 -
Water Research Sep 2018UV based advanced oxidation processes (UV-AOPs) that efficiently eliminate organic pollutants during water treatment have been the subject of numerous investigations.... (Review)
Review
UV based advanced oxidation processes (UV-AOPs) that efficiently eliminate organic pollutants during water treatment have been the subject of numerous investigations. Most organic pollutants are not completely mineralized during UV-AOPs but are partially oxidized into transformation products (TPs), thereby adding complexity to the treated water and posing risks to humans, ecological systems, and the environment. While the degradation kinetics and mechanisms of pollutants have been widely documented, there is little information about the risks associated with TPs. In this review, we have collated recent knowledge about the harmful TPs that are generated in UV/HO and UV photocatalysis, two UV-AOPs that have been studied extensively. Toxic and assimilable TPs were ubiquitously observed in more than 80% of UV-AOPs of organic pollutants, of which the toxicity and assimilability levels changed with variations in the reaction conditions, such as the UV fluence and oxidant dosage. Previous studies and modeling assessments showed that toxic and assimilable TPs may be generated during hydroxylation, dealkylation, decarboxylation, and deamination. Among various reactions, TPs generated from dealkylation and decarboxylation were generally less and more toxic than the parent pollutants, respectively; TPs generated from decarboxylation and deamination were generally less and more assimilable than the parent pollutants, respectively. There is also potential concern about the sensory-unpleasant TPs generated by oxidations and subsequent metabolism of microorganisms. In this overview, we stress the need to include both the concentrations of organic pollutants and the evaluations of the risks from TPs for the quality assessments of the water treated by UV-AOPs.
Topics: Animals; Color; Humans; Hydrogen Peroxide; Odorants; Oxidants; Oxidation-Reduction; Risk; Taste; Ultraviolet Rays; Water Pollutants, Chemical; Water Purification
PubMed: 29783164
DOI: 10.1016/j.watres.2018.05.005 -
Nature Communications May 2022Removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hampered by the excessive input of energy and/or chemicals as well as the...
Removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hampered by the excessive input of energy and/or chemicals as well as the large amounts of residuals resulting from incomplete mineralization. Herein, we report a new water purification paradigm, the direct oxidative transfer process (DOTP), which enables complete, highly efficient decontamination at very low dosage of oxidants. DOTP differs fundamentally from AOPs and adsorption in its pollutant removal behavior and mechanisms. In DOTP, the nanocatalyst can interact with persulfate to activate the pollutants by lowering their reductive potential energy, which triggers a non-decomposing oxidative transfer of pollutants from the bulk solution to the nanocatalyst surface. By leveraging the activation, stabilization, and accumulation functions of the heterogeneous catalyst, the DOTP can occur spontaneously on the nanocatalyst surface to enable complete removal of pollutants. The process is found to occur for diverse pollutants, oxidants, and nanocatalysts, including various low-cost catalysts. Significantly, DOTP requires no external energy input, has low oxidant consumption, produces no residual byproducts, and performs robustly in real environmental matrices. These favorable features render DOTP an extremely promising nanotechnology platform for water purification.
Topics: Decontamination; Environmental Pollutants; Oxidants; Water; Water Pollutants, Chemical
PubMed: 35637224
DOI: 10.1038/s41467-022-30560-9 -
Accounts of Chemical Research Apr 2019Formation of iodinated disinfection byproducts (I-DBPs) in drinking water has become an emerging concern. Compared to chlorine- and bromine-containing DBPs, I-DBPs are...
Formation of iodinated disinfection byproducts (I-DBPs) in drinking water has become an emerging concern. Compared to chlorine- and bromine-containing DBPs, I-DBPs are more toxic, have different precursors and formation mechanisms, and are unregulated. In this Account, we focus on recent research in the formation of known and unknown I-DBPs in drinking water. We present the state-of-the-art understanding of known I-DBPs for the six groups reported to date, including iodinated methanes, acids, acetamides, acetonitriles, acetaldehyde, and phenols. I-DBP concentrations in drinking water generally range from ng L to low-μg L. The toxicological effects of I-DBPs are summarized and compared with those of chlorinated and brominated DBPs. I-DBPs are almost always more cytotoxic and genotoxic than their chlorinated and brominated analogues. Iodoacetic acid is the most genotoxic of all DBPs studied to date, and diiodoacetamide and iodoacetamide are the most cytotoxic. We discuss I-DBP formation mechanisms during oxidation, disinfection, and distribution of drinking water, focusing on inorganic and organic iodine sources, oxidation kinetics of iodide, and formation pathways. Naturally occurring iodide, iodate, and iodinated organic compounds are regarded as important sources of I-DBPs. The apparent second-order rate constant and half-lives for oxidation of iodide or hypoiodous acid by various oxidants are highly variable, which is a key factor governing the iodine fate during drinking water treatment. In distribution systems, residual iodide and disinfectants can participate in reactions involving heterogeneous chemical oxidation, reduction, adsorption, and catalysis, which may eventually affect I-DBP levels in finished drinking water. The identification of unknown I-DBPs and total organic iodine analysis is also summarized in this Account, which provides a more complete picture of I-DBP formation in drinking water. As organic DBP precursors are difficult to completely remove during the drinking water treatment process, the removal of iodide provides a cost-effective solution for the control of I-DBP formation. This Account not only serves as a reference for future epidemiological studies to better assess human health risks due to exposure to I-DBPs in drinking water but also helps drinking water utilities, researchers, regulators, and the general public understand the formed species, levels, and formation mechanisms of I-DBPs in drinking water.
Topics: Aldehydes; Disinfectants; Drinking Water; Gas Chromatography-Mass Spectrometry; Half-Life; Iodides; Oxidants; Oxidation-Reduction; Phenols; Water Purification
PubMed: 30919613
DOI: 10.1021/acs.accounts.8b00641 -
Chemosphere Jan 2021Micropollutants like pharmaceuticals, hormones and pesticides are still found in treated municipal wastewater. An effective way to degrade micropollutants is to use...
Micropollutants like pharmaceuticals, hormones and pesticides are still found in treated municipal wastewater. An effective way to degrade micropollutants is to use oxidants such as ozone or hydroxyl radicals. We designed an innovative experimental protocol combining batch experiments and a study of a full-scale WWTP to understand and predict the removal via ozonation of typical micropollutants present in secondary treated effluents. First, the direct and indirect ozonation of 47 organic micropollutants was scrutinized, then a model was developed and calibrated to simulate the ozone transfers and the oxidation of the selected micropollutants. The kinetic rate constants between micropollutants and ozone or hydroxyl radicals (OH) were determined for 47 micropollutants found in secondary treated effluent. We classified the micropollutants into low- (k between 1.50 and 4.47 × 10 L mol. s), medium- (k between 1.31 × 10 and 4.92 × 10 L mol. s) and high-oxidizable groups (k between 9.44 × 10 and 8.18 × 10 L mol. s) according to their reactivity with ozone, and identified the major degradation pathways for all 47 micropollutants. Micropolluants of the low- and medium-oxidizable groups were largely eliminated by the indirect pathway, at 96% and 84% on average, respectively. In contrast, micropollutants of high-oxidizable group were largely eliminated by the direct pathway, at 98% on average. The model successfully simulated the direct and indirect ozonation of the 47 micropollutants in batch experiments and confirmed the predominant pathways for each group. Finally, the model was applied to the full-scale ozonation process operated at an ozone dose ranging from 0.5 to 1.6 gO. gDOC. The model was found to reliably simulate the ozonation-process removal efficiencies for 4 micropollutants (imidacloprid, fenofibric acid, metronidazole and ketoprofen).
Topics: Hydroxyl Radical; Kinetics; Models, Theoretical; Oxidants; Oxidation-Reduction; Ozone; Wastewater; Water Pollutants, Chemical; Water Purification
PubMed: 33182096
DOI: 10.1016/j.chemosphere.2020.127969 -
Scientific Reports Feb 2020Felids have a high incidence of chronic kidney disease (CKD), for which the most common renal lesion is chronic interstitial nephritis (CIN). CIN can be induced by...
Felids have a high incidence of chronic kidney disease (CKD), for which the most common renal lesion is chronic interstitial nephritis (CIN). CIN can be induced by tissue oxidative stress, which is determined by the cellular balance of pro- and anti-oxidant metabolites. Fish-flavoured foods are more often fed to cats than dogs, and such foods tend to have higher arsenic content. Arsenic is a pro-oxidant metallic element. We propose that renal accumulation of pro-oxidant elements such as arsenic and depletion of anti-oxidant elements such as zinc, underpin the high incidence of CIN in domestic cats. Total arsenic and other redox-reactive metal elements were measured in kidneys (after acid-digestion) and urine (both by inductively-coupled plasma-mass spectrometry) of domestic cats (kidneys, n = 56; urine, n = 21), domestic dogs (kidneys, n = 54; urine, n = 28) and non-domesticated Scottish Wildcats (kidneys, n = 17). Renal lesions were graded by severity of CIN. In our randomly sampled population, CIN was more prevalent in domestic cat versus domestic dog (51%, n = 32 of 62 cats; 15%, 11 of 70 dogs were positive for CIN, respectively). CIN was absent from all Scottish wildcats. Tissue and urinary (corrected for creatinine) arsenic content was higher in domestic cats, relative to domestic dogs and wildcats. Urine arsenic was higher in domestic cats and dogs with CIN. Arsenobetaine, an organic and relatively harmless species of arsenic, was the primary form of arsenic found in pet foods. In summary, the kidneys of domestic cats appear to have greater levels of pro-oxidant trace elements, as compared to dogs and wildcats. Since there was no difference in renal arsenic levels in cats with or without CIN, renal arsenic accumulation does not appear a primary driver of excess CIN in cats. Given clear differences in renal handling of pro vs. anti-oxidant minerals between cats and dogs, further in vivo balance studies are warranted. These may then inform species-specific guidelines for trace element incorporation into commercial diets.
Topics: Animal Feed; Animals; Antioxidants; Arsenic; Arsenicals; Cat Diseases; Cats; Dogs; Female; Fibrosis; Fishes; Food Contamination; Kidney; Male; Mass Spectrometry; Nephritis, Interstitial; Oxidants; Oxidation-Reduction; Reactive Oxygen Species; Renal Insufficiency, Chronic; Trace Elements
PubMed: 32081923
DOI: 10.1038/s41598-020-59876-6 -
Chemosphere Nov 2022In recent years, there has been an increasingly growing interest regarding the use of electrochemical advanced oxidation processes (EAOPs) which are considered highly... (Review)
Review
Decontamination of wastewater containing contaminants of emerging concern by electrooxidation and Fenton-based processes - A review on the relevance of materials and methods.
In recent years, there has been an increasingly growing interest regarding the use of electrochemical advanced oxidation processes (EAOPs) which are considered highly promising alternative treatment techniques for addressing environmental issues related to pollutants of emerging concern. In EAOPs, electrogenerated oxidizing agents, such as hydroxyl radical (HO), can react non-selectively with a wide range of organic compounds, degrading and mineralizing their structures to unharmful molecules like CO, HO, and inorganic ions. To this date, a broad spectrum of advanced electrocatalysts have been developed and applied for the treatment of compounds of interest in different matrices, specifically aiming at enhancing the degradation performance. New combined methods have also been employed as alternative treatment techniques targeted at circumventing the major obstacles encountered in Fenton-based processes, such as high costs and energy consumption, which still contribute significantly toward inhibiting the large-scale application of these processes. First, some fundamental aspects of EAOPs will be presented. Further, we will provide an overview of electrode materials which have been recently developed and reported in the literature, highlighting different anode and cathode structures employed in EAOPs, their main advantages and disadvantages, as well as their contribution to the performance of the treatment processes. The influence of operating parameters, such as initial concentrations, pH effect, temperature, supporting electrolyte, and radiation source, on the treatment processes were also studied. Finally, hybrid techniques which have been reported in the literature and critically assess the most recent techniques used for evaluating the degradation efficiency of the treatment processes.
Topics: Carbon Dioxide; Decontamination; Electrochemical Techniques; Electrodes; Hydrogen Peroxide; Hydroxyl Radical; Oxidants; Oxidation-Reduction; Wastewater; Water Pollutants, Chemical
PubMed: 35952792
DOI: 10.1016/j.chemosphere.2022.135763 -
Scientific Reports Mar 2022The idea of applying ultrasound (US) as a green activation method in chemical transformations, especially in catalytic alcohol oxidations, technically and ecologically...
The idea of applying ultrasound (US) as a green activation method in chemical transformations, especially in catalytic alcohol oxidations, technically and ecologically appeals to chemists. In the present work, as an attempt to fulfill the idea of designing an eco-friendly system to oxidize alcoholic substrates into corresponding aldehydes, we developed multifunctional tungstate-decorated CQD base catalyst, A-CQDs/W, and examined its sonooxidation performance in presence of HO as a green oxidant in aqua media. By comparing the catalyst performance in oxidize benzyl alcohol as a testing model to benzaldehyde (BeOH) prior and after US irradiation-trace vs 93%- the key role of ultrasonic irradiation in achieving high yield is completely appreciated. Exceptional thermal and compression condition that is created as a result of acoustic waves is in charge of unparalleled yield results in this type of activation method. The immense degree of reagent interaction in this method, ensures the maximum yield in notably low time, which in turn leads to decrease in the number of unreacted reagents and by-products. Meanwhile, the need for using toxic organic solvents and hazardous oxidants, auxiliaries and phase transfer catalyst (PTC) is completely obviated.
Topics: Alcohols; Aldehydes; Catalysis; Hydrogen Peroxide; Oxidants; Tungsten Compounds
PubMed: 35233016
DOI: 10.1038/s41598-022-06874-5