ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2022
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IF 11.357
Wenjie Kuang,Zhang Yan,Jinxiu Chen,Xiaotang Ling,Wenxiao Zheng,Weijun Huang,Chunhua Feng
Electrochemical oxidation has been demonstrated to be a useful method for removing biorefractory organic pollutants in mature landfill leachate but suffers from low efficiency in eliminating ammonium because of its resistance to being oxidized by HO• or free chlorine (FC) at decreased pH. Here, we propose a new bipolar membrane-electrochlorination (BPM-EC) process to address this issue. We found that the BPM-EC system was significantly superior to both the undivided and divided reactors with monopolar membranes in terms of elevated rate of ammonium removal, attenuated generation of byproducts (e.g., nitrate and chloramines), increased Faradaic efficiency, and decreased energy consumption. Mechanistic studies revealed that the integration of BPM was helpful in creating alkaline environments in the vicinity of the anode, which facilitated production of surface-bound HO• and FC and eventually promoted in situ generation of ClO•, a crucial reactive species mainly responsible for accelerating ammonium oxidation and selective transformation to nitrogen. The efficacy of BPM-EC in treating landfill leachates with different ammonium concentrations was verified under batch and continuous-flow conditions. A kinetic model that incorporates the key parameters was developed, which can successfully predict the optimal number of BPM-EC reactors (e.g., 2 and 5 for leachates containing 589.4 ± 5.5 and 1258.1 ± 9.6 mg L–1 NH4+-N, respectively) necessary for complete removal of ammonium. These findings reveal that the BPM-EC process shows promise in treating ammonium-containing wastewater, with advantages that include effectiveness, adaptability, and flexibility.
研究领域:
环境科学
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电化学工程
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Wubin Liao,Peng Liao,Zheng Wang,Chenggang Ci,Shiwei Xie
The dephosphorylation of N-containing phosphonates is crucial for mitigating their potential ecological risks and enabling phosphorus resource recovery. Here, we first show that the electrochlorination process outperforms other advanced oxidation methods in terms of conversion efficiency and rate constants for orthophosphate production. The high efficacy of electrochlorination process is primarily attributed to the generation of hypochlorous acid (HClO) under neutral pH conditions, as substantiated by a combination of speciation analysis, quantitative assessments, and quenching experiments. Furthermore, density functional theory (DFT) calculation and LC-MS measurements show that the degradation of nitrilotris-methylenephosphonic acid (NTMP) by HClO occurs spontaneously, with a preferential cleavage of the C P bond over the C N bond, thereby facilitating the efficiency of the dephosphorylation reaction. Altogether, our findings provide key insights into the role of reactive chlorine species in the degradation of N-containing phosphonates, offering valuable evidence for the development of next-generation, more effective phosphorus recovery strategies.
研究领域:
环境科学
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化学工程
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计算化学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Peiying Liu,Haiyang He,Liangjie Wang,Pingzhou Duan,Lijie Duan,Feng Qian,Xianghua Wen,Yonghui Song
Reverse osmosis concentrate (ROC) from the secondary effluent in municipal wastewater reclamation contains emerging pollutants (EPs) that require further treatment, as these EPs may otherwise pose risks to human health and ecological balance. Since ROC has relatively high salinity, Electrochlorination (E-Cl) could exactly be a promising technology for its EPs removal. However, a comprehensive and systematic investigation has yet to be carried out. In this study, targeted at E-Cl process for the ROC treatment, a series of conscientiously designed experiments were conducted to evaluate the removal performance of carbamazepine (CBZ), investigate the effects of operating conditions and water matrix on the CBZ removal, and reveal its reaction mechanisms. An excellent CBZ removal efficiency of 99.8 % was achieved within 30 min at 2 mA cm −2 in 5 mM NaCl solution. Among water matrix components, SO 4 2- , NO 3 – , PO 4 3- and NH 4 + showed minimal effects, whereas HCO 3 – and humic acid had significant influences on the CBZ removal. The roles of ClO• and Cl 2 • - radicals in the E-Cl process were clarified through quenching experiments combined with electron paramagnetic resonance and radical probe tests. The steady-state concentrations of ClO• (88.95 × 10 -14 M) and Cl 2 • - (493.02 × 10 -14 M) were much higher than those of HO• (6.91 × 10 -14 M). Both ClO• and Cl 2 • - played key roles in CBZ degradation in the E-Cl process. Probable degradation pathways of CBZ were proposed based on the intermediates identification and density function theory (DFT) calculations. This study demonstrates the potential of E-Cl systems for effective EPs removal in ROC, providing mechanistic insights for practical applications.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
高影响因子
WATER RESEARCH
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2024
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IF 11.4
YeXin Liang,Mingzhe Yuan,Haimei Cheng,Haiqin Lv,Lei Zhao,JiaLi Tang,Yong Feng,Ying Huang,Qingguo Meng
Electrochemical methods for treating phenolic wastewater have been widely studied, with most research focusing primarily on the anode, while the cathode has generally served as a counter electrode. This study aims to enhance the electrocatalytic process by developing a new Fe/Cu-based cathode using a simple redox method. We created a CuO Cu@Fe-Fe 2 O 3-x (0 < x < 1, combining Fe 2 O 3 and FeO) electrode, referred to as CCFFO, to facilitate the electro-Fenton process without requiring additional H 2 O 2 or Fe 2+ . In our electrolysis system with NaCl as the electrolyte for electro-chlorination process, phenol concentration was reduced from 100 mg/L to below 0.5 mg/L within 10 min. Optimal experimental conditions were determined by evaluating various parameters such as chloride electrolyte concentration, current density, electrode plate spacing, aeration, pH, and cathode types. Additionally, the role of chloride ions in phenol degradation was investigated through free radical quenching experiments. A 500-hour continuous flow experiment demonstrated the durability of the CCFFO cathode. GC/MS analysis identified intermediates formed during phenol degradation and the underlying catalytic mechanism was explored. The results indicate that the electro-chlorination process at the anode is the primary driver of phenol degradation, assisted by the electro-Fenton process on the CCFFO cathode. The CCFFO cathode effectively prevents the production of harmful by-products like perchlorate. The degradation efficiencies of chemical oxygen demand (COD) and total organic carbon (TOC) were 63.5 % and 80.25 %, respectively. Achieving a phenol degradation efficiency of 99.5 % within 10 min, the CCFFO cathode and electrolytic system show significant potential for wastewater treatment applications.
研究领域:
环境科学
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电化学工程
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
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2023
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IF 12.8
Sainan Sun,Meng Qiao,Guanghua Huang,Junke Zhang,Bo Yang,Xu Zhao
Phosphonate used as scale inhibitor is a non-negligible eutrophic contaminant in corresponding polluted waters. Besides, its conversion to orthophosphate (ortho-P) is a precondition for realizing bioavailable phosphorus recovery. Due to the feeble degradation efficiency with less than 30 % from classical Fenton commonly used in industrial wastewater treatment and itself vulnerable to strong inhibition interference of matrix chloride ions, we proposed an electrochemical approach to transform the native salt in the solution into oxidizing substances, sort of achieving beneficial utilization of matrix waste, and enhanced the ortho-P conversion rate of 1-Hydroxyethane-1,1-diphosphonic acid (HEDP) to 89.2 % (± 3.6 %). In electrochlorination system, it was found that HEDP rapidly complexed with Fe(II) and then coordinated in-situ Fe(III) to release free HEDP via intramolecular metal-ligand electron transfer reaction. The subsequent degradation mainly rooted in the oxidation of pivotal reactive species HClO, Fe IV O 2+ and 1 O 2 , causing C-P and C C bonds to fracture in sequence. Eventually the organically bound phosphorus of HEDP was recovered as ortho-P. This study acquainted the audiences with the rare mechanism of chloridion-triggered HEDP degradation under electrochemical way, as well as offered a feasible technology for synchronous transformation of organically bound phosphorus to ortho-P and elimination from phosphonates.
研究领域:
环境科学
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废水处理
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电化学工程
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2025
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IF 7.2
Xinwei Xu,Hui Sun,Jueyao Li,Yongming Tang
The reactive species of electrochlorination (E-Cl) in the ultrahigh salinity water (1 %-15 % NaCl) were investigated using pyridine (Pyr) as the model pollutant. No • OH signal can be detected for the E-Cl process in the ultrahigh salinity water. The free radicals are dominantly composed of the reactive chlorine species (RCS) such as Cl • , Cl 2 •− and ClO • . Moreover, the steady concentrations of Cl 2 •− and ClO • , and thus their contributions to the Pyr removal, are higher than that of Cl • . In 15 % NaCl solution, at the current density lower than 3 mA cm −2 , the RCS cannot be generated. Compared with the RCS species, the contribution of free chlorine (FC) to the Pyr removal is slightly higher due to the abundant FC generated during the E-Cl process. However, the reactivity of RCS to Pyr is much higher than that of FC. The second-order reaction rate constants of Cl • , Cl 2 •− , ClO • and FC with Pyr are 4.1 × 10 9 M −1 s −1 , 8.0 × 10 6 M −1 s −1 , 2.2 × 10 5 M −1 s −1 and 1.9 × 10 −3 M −1 s −1 , respectively. Among the background substances, SO 4 2- ions shows the significantly inhibitory effect on the Pyr degradation. Furthermore, the degradation pathway of Pyr was also proposed in the study.
研究领域:
环境化学
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电化学
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水处理
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污染物降解
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2025
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IF 11.3
Sainan Sun,Guanghua Huang,Jiawei Tang,Fazhi Xie,Xiao Wang,Qiang Guo,Hongshuai Kan,Meng Qiao,Yanpeng Liu,Yi Liu,Zixiao Zhu,Xu Zhao,Ran Mao,Bo Yang
Considering the potential eutrophication risk of phosphonate and scarcity of phosphorus resources, the oxidation of organically-bound phosphorus to orthophosphate (ortho-P) is an important prerequisite for high-value phosphorus recovery. This study investigated efficiency and mechanism of different categories of phosphonates oxidation to ortho-P by classical Fenton and practical electrochlorination Fenton-like processes. The target phosphonates included two categories: nitrogen-free phosphonates (NF-PPs), i.e. 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and 1-Hydroxyethane-1,1-diphosphonic acid (HEDP), and aminophosphonates (A-PPs), i.e. Nitrilotris(methylene phosphonic acid) (NTMP) and diethylenetriamine penta(methylene phosphonic acid) (DTPMP). The results showed that ortho-P conversion for both NF-PPs and A-PPs by classical Fenton process were below 35 %, even though the content of Fe(II) and H 2 O 2 were high enough to neglect the influence of phosphonate-Fe(II) complexation on Fenton reaction initiation. While electrochlorination Fenton-like process greatly enhanced ortho-P conversion of HEDP, NTMP and DTPMP. Potent oxidation relied on generation of HClO, Fe IV O 2+ , and 1 O 2 rather than HO•. In particular, PBTC failed to decompose effectively by electrochlorination Fenton-like process possibly due to chlorine resistance. The non-N-element group was inferred to serve as a decisive role in phosphonates decomposition. This study provided the first systematic description of oxidation rules and mechanism characteristics of diverse phosphonates under classical Fenton and electrochlorination Fenton-like treatment.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2020
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IF 7.864
Meihui Ren,Haijun Zhang,Yun Fan,Dan Wang,Rong Cao,Yuan Gao,Jiping Chen
Thiourea can effectively inhibit the formation of highly toxic chlorinated aromatics in postcombustion zone. However, the inhibition mechanism was still not adequately understood. In this study, naphthalene was adopted as a model aromatic compound to investigate the inhibition effect and mechanism of thiourea on the formation of chlorinated aromatics via electrophilic chlorination over Cu and Fe chlorides. Thiourea addition resulted in the reductions of 77.6–99.8% and 36.4–98.1% in the yield of polychlorinated naphthalenes from naphthalene chlorination mediated by CuCl2 and FeCl3 at 150–300 °C, respectively. The inhibition efficiency of chlorination presented a decreasing tendency with increasing reaction temperature and O2 content in flue gas. X-ray diffraction analysis revealed that the thiourea-induced reduction of highly active Cu (II) and Fe (III) chlorides to less active Cu (I) and Fe (II) chlorides was a primary mechanism for inhibiting aromatic chlorination. [thiourea–Cu]+ complex generated during the reduction process could be transformed into CuS and Cu2S, and isomeric reaction product NH4SCN could react with Cu2+ to produce Cu(SCN)2 and then also form Cu sulfides, suggesting sulfidization of Cu chloride was another important inhibition mechanism. Chlorination inhibition induced by the volatile decomposition products of thiourea might only play a minor role.
研究领域:
环境科学
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化学工程
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催化
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燃烧化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）