CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Yongkui Li,Xianjin Qi,Guohua Li,Hua Wang
Nonferrous smelting wastewaters containing high levels of arsenic and sulfuric acid threaten human health and ecological environments due to insufficient disposal technologies and/or possible leakages during transportation to long-term storage facilities. Chemical precipitation is one important route for arsenic removal and immobilization via the formation of arsenic-stabilized minerals. In this study, we propose a new strategy for the treatment of wastewaters containing high levels of arsenic using pyrite as an in situ S and Fe source to prepare environmentally friendly scorodite and As 2 S 3 precipitates. Dissolved pyrite release (S-II) and Fe (II) ions in highly acidic wastewater, both of which drive arsenic precipitation. Sulfide ions readily react with As(III) to generate the stable As 2 S 3 while Fe(II)/As(III) were oxidized to Fe(III)/As(V) by H 2 O 2 . The reaction between Fe(III) and As(V) took place on the pyrite surface as a nucleation site to form amorphous ferric arsenate that ultimately transformed into crystalline scorodite. Sulfide ions were oxidized to H 2 SO 4 that further promoted pyrite dissolution. Up to 99.4% of arsenic was successfully removed from copper smelting wastewaters with an initial arsenic concentration of 11200 mg/L. The concentration of leached As from the As-bearing precipitate was 1.78 mg/L under optimized conditions, which were: a 1.4 FeS 2 /As molar ratio, an initial solution pH of 2, an H 2 O 2 /As molar ratio of 1%, a reaction temperature of 90 °C, and a reaction time of 12 h. In summary, a prospective process successfully shows arsenic removal and immobilization from smelting wastewater, and further demonstrates the potential for the efficient and affordable disposal of wastewater.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Na Chen,Yichao Wan,Guangming Zhan,Xiaobing Wang,Meiqi Li,Lizhi Zhang
Solar light driven organoarsenicals degradation and simultaneous inorganic arsenic immobilization with naturally abundant hematite is very promising for organoarsenicals remediation, but suffers from the fast electron-hole charge recombination of hematite. Herein, we report that oxalate, widely existed in soil and water environments, can greatly enhance the photocatalytic molecular oxygen activation of hematite to degrade a typical organoarsenical roxarsone and immobilize the resulted inorganic arsenic. It was found that oxalate could chelate with surface Fe(III) of hematite to generate plenty of •OH via a surface Fe(III)/Fe(II) cycle mediated oxygen molecular activation process under a simulated solar light, and thus induced 85.1% of roxarsone transformation into inorganic arsenic species, mainly As(V), within 6 h. The generated As(V) could be further adsorbed on hematite surface with prolonging the reaction time to 24 h in dark, avoiding secondary pollution. More importantly, hematite was reusable for the simulated solar light driven roxarsone degradation and As(V) immobilization in the presence of oxalate. This study offers a green and effective strategy for organoarsenicals remediation, and also sheds light on the environmental effects of iron oxides and oxalate.
研究领域:
环境科学
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光化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2024
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IF 8.2
Wenli Jia,Zhi Yu,Junfeng Chen,Jian Zhang,Jian Zhu,Wentao Yang,Ruidong Yang,Pan Wu,Shengsen Wang
Nitrate nitrogen fertilizer was usually used to mitigate arsenic (As) release and mobilization in the anaerobic contaminated paddy soil. However, the effect of the interplay between nitrate fertilizer and biochar on As availability as well as the involved mechanism were poorly understood. Herein, the effects and mechanisms of biochar, nitrate fertilizer, and biochar-based nitrate fertilizer on the availability of As in the contaminated paddy soil were investigated via a microcosm incubation experiment. Results indicated that the application of biochar-based nitrate fertilizer significantly lessened the available As concentration in the contaminated paddy soil from 3.01 ± 0.03 (control group) to 2.24 ± 0.08 mg kg −1 , which presented an immobilization efficiency of 26.6 % better than those of individual biochar (13.5 %) and nitrate fertilizer (17.6 %), exhibiting a synergistic effect. Moreover, the biochar-based nitrate fertilizer also facilitated the transformation of more toxic arsenite in the contaminated soil to less toxic arsenate. Further, biochar-based nitrate fertilizer increased soil redox potential (Eh), dissolved organic carbon, organic matter, and nitrate yet decreased soil pH and ammonium, which changed the microbial community in the soil, enhancing the relative abundance of Bacillus , Arthrobacter , and Paenibacillus . These functional microorganisms drove the coupled transformation between nitrate denitrification and Fe(II) or As(III) oxidation, favoring As immobilization in the anaerobic paddy soil. Additionally, the co-application of biochar offset the negative effect of single nitrate fertilizer on microbial community diversity. Overall, biochar-based nitrate fertilizer could be a promising candidate for the effective immobilization of As in the anaerobic paddy soil. The current research can provide a valuable reference to the remediation of As-contaminated paddy soil and the production of safe rice.
研究领域:
环境科学
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土壤学
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农业
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2021
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IF 7.963
Cheng Ye,Jing Deng,Lingyi Huai,Anhong Cai,Xiao Ling,Hongguang Guo,Qiongfang Wang,Xueyan Li
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.
研究领域:
环境科学
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化学工程
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水处理技术
✓ 已验证
DOI
高影响因子
Biochar
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2024
·Vol. 6
·期 1
·1-14
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IF 13.1
Wang Shengsen,Li Wenjing,Ding Chengyu,Zhang Jian,Zhang Ni,Li Yuncong C.,Gao Bin,Wang Bing,Wang Xiaozhi
Arsenic (As) detoxification in polluted soils by iron-based materials can be mediated by the endogenous soil organic matter (SOM), nevertheless the mechanisms remain unclear. Herein, endogenous SOM in a paddy soil was substantially removed to understand its roles on As immobilization by biochar-supported zero-valent iron (ZVI/BC). The results demonstrated that ZVI/BC application significantly decreased As bioavailability by 64.2% compared with the control soil under the anaerobic condition. XPS and HR-TEM suggested As immobilization by ZVI/BC mainly invoked the formation of ternary complexes (i.e., As-Fe-SOM). However, SOM depletion compromised the efficacy of ZVI/BC for As immobilization by 289.8%. This is likely because SOM depletion increased the fulvic acid and OH − contents in soils. Besides, ZVI/BC increased the proportion of As(III) in available As fraction, but SOM depletion altered the mechanisms associated with As(V) reduction. That is, As(V) reduction resulted from the reductive capacity of ZVI in the pristine soil, but the As(V)-reducing bacteria contributed greater to As(V) reduction in the SOM-depleted soil. Additionally, SOM depletion boosted the abundances of Fe(III)- and As(V)-reducing bacteria such as Bacillus and Ammoniphilus in soils, which enhanced the dissimilatory arsenate reduction. Thus, this work highlighted the importance of SOM in the remediation of As-contaminated soils by ZVI/BC. Graphical Abstract
研究领域:
环境科学
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土壤化学
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微生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Yuxi Zhang,Yamin Deng,Jiangkai Xue,Yihan Cheng,Yulun Nie,Kunfu Pi,Yao Du,Xianjun Xie,Jianbo Shi,Yanxin Wang
The environmental fate of arsenic (As) relies substantially on its speciation, which occurs frequently coupled to the redox transformation of manganese. While trivalent manganese (Mn(III)), which is known for its high reactivity, is believed to play a role in As mobilization by iron (oxyhydr)oxides in dynamic aquifers, the exact roles and underlying mechanisms are still poorly understood. Using increasingly complex batch experiments that mimick As-affected aquifer conditions in combination with time-resolved characterization, we demonstrate that Mn(III)-NOM complexes play a crucial role in the manganese-mediated immobilization of As(III) by ferrihydrite and goethite . Under anaerobic condition , Mn(III)-fulvic acid (FA) rapidly oxidized 31.8% of aqueous As(III) and bound both As(III) and As(V). Furthermore, Mn(III)-FA exerted significantly different effects on the adsorption of As by ferrihydrite and goethite. Mn(III)-FA increased the adsorption of As by 6–16% due to the higher affinity of oxidation-produced As(V) for ferrihydrite under circumneutral conditions. In contrast, As adsorption by crystalline goethite was eventually inhibited due to the competitive effect of Mn(III)-FA. To summarize, our results reveal that Mn(III)-NOM complexes play dual roles in As retention by iron oxides , depending on the their crystallization. This highlights the importance of Mn(III) for the fate of As particularly in redox fluctuating groundwater environments.
研究领域:
环境科学
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地球化学
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水文地质学
✓ 已验证
DOI
PubMed
高影响因子
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