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Water Research Aug 2023The widespread occurrence of p-arsanilic acid (p-ASA) in natural environments poses big threats to the biosphere due to the generation of toxic inorganic arsenic (i.e.,...
The widespread occurrence of p-arsanilic acid (p-ASA) in natural environments poses big threats to the biosphere due to the generation of toxic inorganic arsenic (i.e., As(III) and As(V), especially As(III) with higher toxicity and mobility). Oxidation of p-ASA or As(III) to As(V) followed by precipitation of total arsenic using Fe-based advanced oxidation processes demonstrated to be a promising approach for the treatment of arsenic contamination. This study for the first time investigated the efficiency and inherent mechanism of p-ASA and As(III) oxidation by Fe(II)/peracetic acid (Fe(II)/PAA) and PAA processes. p-ASA was rapidly degraded by the Fe(II)/PAA process within 20 s at neutral to acidic pHs under different conditions, while it was insignificantly degraded by PAA oxidation alone. Lines of evidence suggested that hydroxyl radicals and organic radicals generated from the homolytic OO bond cleavage of PAA contributed to the degradation of p-ASA in the Fe(II)/PAA process. p-ASA was mainly oxidized to As (V), NH, and p-aminophenol by the Fe(II)/PAA process, wherein the aniline group and its para position were the most vulnerable sites. As(III) of concern was likely generated as an intermediate during p-ASA oxidation and it could be readily oxidized to As(V) by the Fe(II)/PAA process as well as PAA alone. The in-depth investigation demonstrated that PAA alone was effective in the oxidation of As(III) under varied conditions with a stoichiometric molar ratio of 1:1. Efficient removal (> 80%) of total arsenic during p-ASA oxidation by Fe(II)/PAA process or during As(III) oxidation by PAA process with additional Fe(III) in synthetic or real waters were observed, mainly due to the adsorptive interactions of amorphous ferric (oxy)hydroxide precipitates. This study systematically investigates the oxidation of p-ASA and As(III) by the Fe(II)/PAA and PAA processes, which is instructive for the future development of arsenic remediation technology.
Topics: Ferric Compounds; Arsenic; Arsanilic Acid; Peracetic Acid; Arsenites; Oxidation-Reduction; Ferrous Compounds; Water Pollutants, Chemical; Hydrogen Peroxide
PubMed: 37262947
DOI: 10.1016/j.watres.2023.120091 -
Water Research Sep 2022As a feed additive, p-arsanilic acid (p-ASA) is hardly metabolized in animal bodies and is excreted chemically unchanged via feces and urine, which can be transformed...
As a feed additive, p-arsanilic acid (p-ASA) is hardly metabolized in animal bodies and is excreted chemically unchanged via feces and urine, which can be transformed into more toxic inorganic arsenic species and other organic by-products upon degradation in the aquatic environment. In this study, UV-LED/persulfate (PS)/Fe(Ⅲ) and UV-LED/peroxymonosulfate (PMS)/Fe(Ⅲ) processes were developed to remove p-ASA and immobilize the formed inorganic arsenic via tuning solution pH. UV-LED/PMS/Fe(Ⅲ) (90.8%) presented the best performance for p-ASA degradation at pH 3.0, and the p-ASA degradation in these processes both followed the pseudo-first-order kinetics. The ∙OH played the major role in UV-LED/PS/Fe(Ⅲ) and UV-LED/PMS/Fe(Ⅲ) systems. Solution pH greatly affected the p-ASA degradation and the maximum removal can be achieved at pH 3.0 due to the presence of more Fe(OH)(HO). The dosages of Fe(III) and PMS (PS), SO and HCO significantly influenced the performance of p-ASA oxidation, while HA, Cl and NO slightly affected the p-ASA degradation. According to quantum chemical calculation, radical addition on the C atom in the C-As bond of p-ASA was corroborated to be the dominant reaction pathway by SO∙ and ∙OH. Additionally, the reactive sites and reasonable degradation pathways of p-ASA were proposed based on DFT calculation and HPLC/MS analysis. The release of inorganic arsenic in both processes can be effectively immobilized and the toxicity of the reaction solution dramatically reduced by adjusting solution pH to 6.0. UV-LED/PMS/Fe(Ⅲ) process was found to be more cost-effective than UV-LED/PS/Fe(Ⅲ) process at the low oxidant dosages.
Topics: Animals; Arsanilic Acid; Arsenates; Arsenic; Ferric Compounds; Oxidants; Oxidation-Reduction; Peroxides; Water Pollutants, Chemical
PubMed: 35998556
DOI: 10.1016/j.watres.2022.118989 -
Environmental Science and Pollution... Nov 2021Phenylarsonic acid compounds, which were widely used in poultry and swine production, are often introduced to agricultural soils with animal wastes. Fenton coagulation...
Phenylarsonic acid compounds, which were widely used in poultry and swine production, are often introduced to agricultural soils with animal wastes. Fenton coagulation process is thought as an efficient method to remove them. However, the substituted amino group could apparently influence the removal efficiency in Fenton coagulation process. Herein, we investigated the optimal conditions to treat typical organoarsenic contaminants (p-arsanilic acid (p-ASA) and phenylarsonic acid (PAA)) in aqueous solution based on Fenton coagulation process for oxidizing them and capturing the released inorganic arsenic, and elucidated the influence mechanism of substituted amino group on removal. Results showed that the pH value and the dosage of HO and Fe significantly influenced the performance of the oxidation and coagulation processes. The optimal conditions for removing 20 mg L-As in this research were 40mg L Fe and 60mg L HO (the mass ratio of Fe/HO = 1.5), initial solution pH of 3.0, and final solution pH of 5.0 adjusting after 30-min Fenton oxidation reaction. Meanwhile, the substituted amino group made p-ASA much more easily be attacked by ·OH than PAA and supply one more binding sites for forming complexes with Fe hydrolysates, resulting in 36% higher oxidation rate and 7% better coagulation performance at the optimal conditions.
Topics: Animals; Arsanilic Acid; Hydrogen Peroxide; Iron; Oxidation-Reduction; Swine; Water; Water Pollutants, Chemical
PubMed: 34227010
DOI: 10.1007/s11356-021-15157-x -
Journal of Colloid and Interface Science Jan 2023Organic arsenic pollutant p-arsanilic acid (p-ASA) in wastewater can be converted into highly toxic inorganic arsenic under natural conditions, causing serious harm to...
HYPOTHESIS
Organic arsenic pollutant p-arsanilic acid (p-ASA) in wastewater can be converted into highly toxic inorganic arsenic under natural conditions, causing serious harm to the environment and human health. In this study, an Fe-based metal-organic framework (MOF) material, activated MIL-88A, was synthesized as an adsorbent to remove p-ASA in water.
EXPERIMENTS
Various influencing factors in the material synthesis process, including temperature, time, solution, and annealing process, were investigated to obtain the optimal reaction conditions. The synthesized activated MIL-88A had great porosity and excellent adsorption capacity for p-ASA in a wide pH range (3 ∼ 10). When the pH of the solution was 6, the activated MIL-88A achieved a great adsorption capacity of 813 mg·g for the p-ASA solution with an initial concentration of 0.334 mmol·L. In addition, it still had excellent adsorption capacity after 4 times of repeated usage and washing.
FINDINGS
The adsorption kinetics of p-ASA on the activated MIL-88A followed the pseudo-second-order models, and the adsorption isotherms can be fitted by the Langmuir models well. The adsorption behavior was spontaneous and endothermic, and was dominated by Fe-O-As coordination and hydrogen bonding.
Topics: Humans; Arsanilic Acid; Adsorption; Metal-Organic Frameworks; Arsenic; Wastewater; Water Pollutants, Chemical; Water
PubMed: 36095897
DOI: 10.1016/j.jcis.2022.08.133 -
Environmental Research May 2022In this study, a bimetallic composite catalyst (Co-Fe@C) was fabricated with calcination at high temperature (800 °C) by using Co-MIL-101 (Fe) as the precursor. The...
In this study, a bimetallic composite catalyst (Co-Fe@C) was fabricated with calcination at high temperature (800 °C) by using Co-MIL-101 (Fe) as the precursor. The characterization results showed that the resulted Co-Fe@C composite mainly consisted of carbon, FeCo alloys, FeO, CoO and FeO, and owned evident magnetism. In addition, the Co-Fe@C was employed to activate the peroxydisulfate (PDS) to degrade a representative organic pollutant (p-arsanilic acid, p-ASA) and the main factors were optimized, which involved 0.2 g L of catalyst dosage, 1.0 g L of PDS dosage and 5.0 of initial pH. Under the optimal condition, Co-Fe@C/PDS system could completely degrade p-ASA (20 mg L) in 5 min. In the Co-Fe@C/PDS system, SO·, Fe(IV) and ·OH were the main species during p-ASA degradation. Under the attack of these species, p-ASA was first decomposed into phenols and then transformed into the organics acids and finally mineralized into CO and HO through a series of reactions like hydroxylation, dearsenification, deamination and benzene ring opening. Importantly, most of the released inorganic arsenic species (93.40%) could be efficiently adsorbed by the catalyst.
Topics: Arsanilic Acid; Arsenic; Catalysis; Cobalt; Oxides
PubMed: 34627800
DOI: 10.1016/j.envres.2021.112184 -
The Science of the Total Environment Nov 2020para-arsanilic acid (p-ASA), as a major phenylarsonic feed additive, was used annually in many countries. Once it enters the water environment, p-ASA would be...
para-arsanilic acid (p-ASA), as a major phenylarsonic feed additive, was used annually in many countries. Once it enters the water environment, p-ASA would be transformed into hypertoxic inorganic arsenic species, causing severe arsenic pollution. In this study, magnetic copper ferrite (CuFeO) was applied to activate peroxymonosulfate (PMS) for p-ASA removal and synchronous control of the released inorganic arsenic species. Results showed that CuFeO/PMS system presented favorable oxidation ability and close to 85% of 10 mg/L p-ASA was eliminated under the condition of simultaneous dosing 0.2 g/L CuFeO and 1 mM PMS. The rapid decomposition of p-ASA resulted from homogeneous PMS oxidation and the attack of reactive oxygen species (i.e., SO, HO and O), which was involved the heterogeneous PMS activation through the cycles between Fe(II)/Fe(III) and Cu(II)/Cu(I). Meanwhile, the released inorganic arsenic species during p-ASA degradation were found to be controllable via the adsorption on CuFeO surface and metal hydroxyl groups played the crucial role. CuFeO/PMS system exhibited the stable and efficient performance within the broad range of pH 3.0-11.0. The existence of common anions (Cl, NO, HCO, SO) and humic acid presented the slight inhibition for p-ASA degradation. The reduction of initial p-ASA concentration favored the p-ASA removal. Besides, the catalyst retained a favorable reactivity and stability even after four successive cycles and almost no metal leaching was observed. The rational degradation pathway was mainly involved in the cleavage of AsC bond, oxidation of amino group, substitution and oxidation of hydroxyl group. The transformation of arsenic species could be divided into the release of inorganic arsenic species, the oxidation of As(III) into As(V) and the adsorption of As(V) by CuFeO.
PubMed: 32623153
DOI: 10.1016/j.scitotenv.2020.140587 -
Food Additives & Contaminants. Part A,... May 2021Arsanilic acid (ASA) residue, which is the most common contaminant in edible animal tissues such as pork and liver, has caused environmental and food-safety concerns. In...
Arsanilic acid (ASA) residue, which is the most common contaminant in edible animal tissues such as pork and liver, has caused environmental and food-safety concerns. In this study, direct and indirect competitive fluorescence-linked immunosorbent assays (dc-FLISA and ic-FLISA) incorporating quantum dots (QDs) as the fluorescent label were developed for the first time to detect ASA residues in edible pork and animal liver. Monoclonal antibodies against ASA and rabbit anti-mouse antibody were conjugated to orange QDs with excitation wavelengths at 450 nm, and the QD-Abs served as detection probes. The limits of detection for dc-FLISA and ic-FLISA were 0.11 ng/mL and 0.001 ng/mL, respectively. QD-FLISA was used to analyse spiked samples; recoveries ranged from 80.2%-91.2% in dc-FLISA and 82.5%-91.2% in ic-FLISA, and the coefficients of variations (CV) were less than 12%. Compared with conventional indirect competitive enzyme-linked immunosorbent assay (ic-ELISA), the QD-FLISA described here was more sensitive and accurate in the analysis of ASA residues in animal tissues. Moreover, the results of QD-FLISA correlated well with HPLC. These results indicate that dc-FLISA and ic-FLISA are sensitive and reliable for detection of ASA residues in edible animal tissues.
Topics: Animals; Antibodies, Monoclonal; Arsanilic Acid; Fluorescent Antibody Technique; Food Analysis; Food Contamination; Liver; Pork Meat; Quantum Dots; Swine
PubMed: 33784216
DOI: 10.1080/19440049.2021.1885751 -
The Science of the Total Environment Feb 2022Organoarsenic contaminants existing in water body threat human health and ecological environment due to insufficient bifunctional treatment technologies for...
Multifunctional capacity of CoMnFe-LDH/LDO activated peroxymonosulfate for p-arsanilic acid removal and inorganic arsenic immobilization: Performance and surface-bound radical mechanism.
Organoarsenic contaminants existing in water body threat human health and ecological environment due to insufficient bifunctional treatment technologies for organoarsenic degradation and inorganic arsenic immobilization. In order to safely and efficiently treat organoarsenic contaminants discharged into the aquatic environment, Co-Mn-Fe layered double hydroxide (CoMnFe-LDH) and Co-Mn-Fe layered double oxide (CoMnFe-LDO) were fabricated and employed as peroxymonosulfate (PMS) activator for organoarsenic degradation and inorganic arsenic immobilization, and p-arsanilic acid (p-ASA) was selected as target pollutant. Results demonstrated that the satisfactory removal of p-ASA (100.0%) in both CoMnFe-LDH/PMS and CoMnFe-LDO/PMS systems was obtained within 30 min, and substantial inorganic arsenic adsorption could be achieved (below 0.5 mg/L) in two systems with converting major inorganic arsenic species to arsenate. As XPS, ESR and quenching experiment revealed, the existence and generation of surface-bound radicals in two systems were identified. Based on density functional theory calculation and XPS analysis, the catalytic mechanism of CoMnFe-LDO/PMS system that PMS could be activated via direct electron transfer from adsorbed p-ASA was clarified, which differed from PMS activation via coupling with surface hydroxyl groups in CoMnFe-LDH/PMS system. Catalytic performance assessment under various critical operation parameters indicated that CoMnFe-LDH presented more stable ability of p-ASA removal in a wide pH range and complex aquatic environment. The recycle experiment demonstrated the excellent stability and reusability of CoMnFe-LDH(LDO). Besides, seven degradation products of p-ASA in CoMnFe-LDH/PMS system including phenolic compounds, azophenylarsonic acid, nitrobenzene and benzoquinne were identified by UV-Vis spectra and LC-TOF-MS analysis, and the corresponding degradation pathway was proposed. In summary, compared to CoMnFe-LDO/PMS, CoMnFe-LDH/PMS holds great promise for the development of an oxidation-adsorption process for efficient control of organoarsenic pollutant.
Topics: Arsanilic Acid; Arsenic; Humans; Hydroxides; Peroxides
PubMed: 34571222
DOI: 10.1016/j.scitotenv.2021.150379 -
The Science of the Total Environment Sep 2021p-arsanilic acid (p-ASA) is still widely applied as feed additive in many countries. Accompanied with chemical reactions in the environment, p-ASA will release more...
p-arsanilic acid (p-ASA) is still widely applied as feed additive in many countries. Accompanied with chemical reactions in the environment, p-ASA will release more toxic inorganic arsenic. In order to safely and efficiently treat p-ASA flow washing into the environment, iron encapsulated B/N-doped carbon nanotubes (Fe@C-NB) were fabricated and used as the catalyst for the degradation of p-ASA. The calcination temperature and the dose of the iron salt have significant effects on the structure and properties of the catalysts. We have produced a series of catalysts of the same type to facilitate the degradation of p-ASA. Under optimal conditions of material (Fe@C-NB) syntheses, both 95% degradation of p-ASA and 86% total arsenic immobilization can be obtained with oxidant (Peroxymonosulfate, PMS) and catalyst (Fe@C-NB) treatment after 60 min. The effects of oxidant types (peroxydisulfate (PDS), PMS, hydrogen peroxide (HO)), amount, initial solution pH, inorganic anion, and other reaction conditions were studied in the p-ASA removal. In this Fenton-like reaction, the Fe@C-NB exhibits high efficiency and excellent stability without complex preparation methods; besides, the advantages of short reaction time and natural reaction conditions in Fe@C-NB/PMS system will promote the practical application of Fenton-like.
PubMed: 33933762
DOI: 10.1016/j.scitotenv.2021.147152 -
Environmental Science and Pollution... Mar 2023As a typical wide band gap photocatalyst, titania (TiO) cannot use the visible light and has fast recombination rate of photogenerated electron-hole pairs. Simultaneous...
As a typical wide band gap photocatalyst, titania (TiO) cannot use the visible light and has fast recombination rate of photogenerated electron-hole pairs. Simultaneous introduction of erbium ion (Er) and graphene oxide (rGO) into TiO might overcome these two drawbacks. In this study, Er and rGO were co-doped on TiO to synthesize Er-rGO/TiO photocatalyst through a two-step sol-gel method. Based on the UV-visible diffuse reflectance spectra and photoluminescence spectrum, the introduction of Er and rGO increased the visible light absorption efficiency and enhanced the migration of photogenerated electron. Pure TiO has almost no photocatalytic activity for arsanilic acid (p-ASA) degradation under visible light irradiation. However, while doping with 2.0 mol% Er and 10.0 mol% rGO, the p-ASA could be completely degraded within 50 min by the Er-rGO/TiO photocatalyst under visible light irradiation, and most of produced inorganic arsenic was in situ removed by adsorption from the solution. The reactive oxygen species (ROS) reacting with p-ASA was determined and superoxide radical (O) and singlet oxygen (O) were the dominant ROS for the oxidation of p-ASA and arsenite. This work provides an approach of introducing Er and rGO to enhance the visible light photocatalytic efficiency of TiO.
Topics: Arsanilic Acid; Reactive Oxygen Species; Graphite
PubMed: 36525183
DOI: 10.1007/s11356-022-24627-9