JOURNAL OF THE ELECTROCHEMICAL SOCIETY
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2024
·Vol. 171
·期 9
·096505
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IF 3.1
Zhefei Zhao,Linlin Zhang,Minghao Chen,Ruopeng Yu,Xuyao Yao,Yinghua Xu,Youqun Chu,Xinbiao Mao,Huajun Zheng
Electrochemical selective dechlorination can be regarded as one of the most promising strategies for generating high-valued chemicals. In the electrochemical dechlorination process of 2-chloro-5-trichloromethylpyridine (TCMP), except the anticipated dechlorination products involving 2-chloro-5-dichloromethylpyridine (DCMP), 2-chloro-5-chloromethylpyridine (CCMP), and 2-chloro-5-methylpyridine (CMP), some unexpected oxygen-incorporated products (6-chloronicotinic acid (CNA) and 6-chloronicotinoyl methyl ester (MCN)) can be obtained. Consequently, understanding the electrochemical dechlorination behavior of TCMP is crucial. Our research revealed that the activated Ag electrodes in halide ion solution exhibit enhanced electrochemical activities for electrochemical dechlorination of TCMP, compared with the pure Ag owing to the increased active specific surface areas and charge transfer. Second, oxygen participation in the reaction is a necessary condition for the formation of oxygen-incorporated products. A 100% selectivity of oxygen-incorporated products can be obtained at the potential of −0.6 V vs Ag/AgCl. Conversely, insufficient oxygen may lead to the potential becoming the determining condition that affects the reaction pathways. A more negative potential (−1.2 V vs Ag/AgCl) is conducive to the formation of dechlorination products with 94.2% conversion and 100% selectivity. This study, for the first time, elucidates the electrocatalyst, atmosphere, and potential-dependent activity and selectivity for the two dechlorination pathways of TCMP.
研究领域:
环境科学
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电化学
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DOI
高影响因子
Applied Sciences-Basel
·
2025
·Vol. 15
·期 10
·5673
·
IF 2.5
Rui Li,Ailin Wen,Jing Li
Chloride ions in zinc refining accelerate equipment corrosion and anode and cathode losses, increase lead content, and reduce zinc quality. Therefore, the removal of chloride ions has become a research priority. The existing copper slag dechlorination process has problems such as the solid film barrier leading to impeded mass transfer, product wrapping triggering active site coverage, and incomplete reactions due to insufficient reaction-driving force, leading to low utilization of copper slag, poor dechlorination efficiency, and long reaction times. To address these issues, a new method of deep dechlorination based on the reduction of Cu2+by liquid-phase mass transfer is proposed in this paper. The process utilizes ascorbic acid as a reducing agent, establishes a homogeneous aqueous phase reaction system, breaks through the solid membrane barrier, and avoids the encapsulation of the product layer, achieving efficient dechlorination. The enol structure of ascorbic acid promotes rapid dechlorination through proton-coupled electron transfer (PCET). Thermodynamic calculations show that compared to the current copper slag dechlorination process, this method increases the reaction-driving force by 18.6%, reduces the Gibbs free energy (ΔGθ) by 59.3%, and increases the equilibrium constant by 6.7 × 109times, making the reaction more complete and achieving a higher degree of purification. The experimental results show that under optimized conditions, the chloride ion concentration in the solution decreases from 1 g/L to 0.0917 g/L within 20 min, with a removal rate of 90.8%. The main precipitate is CuCl. This process provides a more efficient solution to the chloride ion contamination problem in the hydrometallurgical zinc refining process.
研究领域:
冶金工程
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化学工艺
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环境科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Dachao Ma,Qingge Feng,Boqing Chen,Xi Cheng,Kao Chen,Jiao Li
In order to reveal the chlorine behavior during hydrothermal carbonization (HTC) of medical waste, polyvinyl chloride and medical waste model (MW) were respectively treated by HTC at temperature ranging from 220 °C to 300 °C for 30 min. HTC products were characterized by Fourier Transform Infrared Spectrometer, X-ray Photoelectron Spectroscopy, etc. It is found that HTC can efficiently remove chlorine from both polyvinyl chloride and MW. The most dramatical dechlorination can be induced by HTC at around 240 °C. With HTC temperature increased, organic chlorine in HT-MW and solid product from polyvinyl chloride HTC (HT-PVC) is decreased. Interestingly, with 240 °C HTC, the organic chlorine of HT-MW was 15.30%, much lower than that of HT-PVC of 86.84%, indicating the cellulosic materials in MW can significantly boost the conversion of organic chlorine into inorganic form in HTC at 240 °C. While spherical particles assigned to HTC of cellulosic materials aggregate at the pores of polyvinyl chloride particle, trapping the release of chlorine into the liquid, consequently to lower dechlorination efficiency compared to that of polyvinyl chloride. Since the chlorine retain in the solid product was mainly in form of inorganic, further dechlorination is potential for MW by combining HTC with leaching/extracting.
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
Journal of Sustainable Metallurgy
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2023
·Vol. 9
·期 3
·1253-1266
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IF 2.4
Huang Jingdong,Li Guangqiang,Yang Xiao
Natural Zn reserves might be exhausted in the following decades. Electric arc furnace (EAF) dust is an essential secondary Zn resource. The recovery of Zn from EAF dust is a critical factor in the sustainable development of the Zn industry and steelmaking industry. Efficient destruction of the ZnFe 2 O 4 crystal structure and separation of Zn and Fe are the key issues to recycle EAF dust. Molten metal chlorides are believed to be effective in breaking the structure of ZnFe 2 O 4 . This work clarifies the distinct reaction behavior between ZnFe 2 O 4 and MgCl 2 or CaCl 2 . Experiments show that although MgCl 2 is a more powerful chlorinating agent, the capability of separating Zn and Fe is not as good as that of CaCl 2 . Fast and selective chlorination of Zn from ZnFe 2 O 4 happens by reacting ZnFe 2 O 4 and MgCl 2 –CaCl 2 mixture. CaCl 2 facilitates the formation of stable Fe-bearing phases, such as MgFe 2 O 4 and Ca 2 Fe 2 O 5 , thereby inhibiting the chlorination of Fe. Moreover, it becomes more effective in promoting the selectivity of chlorinating Zn by increasing temperature after adding CaCl 2 in MgCl 2 . When ZnFe 2 O 4 is subjected to chlorination using a MgCl 2 –CaCl 2 mixture (MgCl 2 –CaCl 2 –ZnFe 2 O 4 molar ratio = 1.5:1.5:1) at 950 °C for 120 min, the process results in a chlorination percentage of over 90% for Zn, with Fe chlorination percentage lower than 5%. These results demonstrate the prospect of efficient separation of Zn from ZnFe 2 O 4 by reaction with molten MgCl 2 –CaCl 2 mixture. Graphical Abstract
研究领域:
冶金工程
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材料科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Yuheng Chen,Longjie Cheng,Pavel Nesterenko,Boqiang Li,Haolin Yang,Xiao Li,Lan Li,Baiyang Chen
Free chlorine (FC), primarily existing as hypochlorite anion in alkaline water (pK a 7.5), could theoretically be analyzed by an ion chromatography (IC) system. However, the feasibility of direct FC detection by IC remains controversial in previous researches. To address this issue, this study systematically examined the fate of FC under varying IC eluent pH, anion exchange column (AEC) types, detectors, and suppression conditions. The results ultimately disprove it and show that the primary obstacle to direct FC analysis with IC system is its transformation: 31 %–41 % became Cl - and 59 %–69 % became immobile organic chloramines in AEC, due to its reaction with quaternary ammonium compounds (QACs) in AECs. Moreover, IC analysis of Cl - might be interfered by coexisting FC, although FC concentrations are typically much lower than Cl - . Eluent suppressor can also consume FC even when residual FC after AEC is limited. In contrast, variations in water pH do not affect FC stability, and a UV detector effectively distinguishes FC from other anions. This study hence for the first time elucidates several FC consumption mechanisms in IC system, which represent key barriers hindering FC analysis by IC, and accordingly provide some guidance on future efforts to develop novel AEC to overcome these barriers.
研究领域:
环境科学
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分析化学
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DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhaofen Xu,Lingfang Tang,Yuanyi Zhou,Gang Lu,Haojie Dong,Mingshan Zhu
Utilizing the immanent salt (Cl – ) in wastewater to generate reactive chlorine species (RCS) satisfies the future needs for sustainable, on-demand, and decentralized ammonia nitrogen (NH 4 + -N) removal. The microstructural evolution of bismuth oxychloride (BiOCl) photocatalyst under irradiation benefits for overcoming the competition between Cl – and H 2 O oxidation and achieving high N 2 selectivity. Herein, internal electric field (IEF) engineering by carbon doping is applied to promote photocatalytic RCS generation rate over BiOCl. The carbon dopant not only enhances the IEF intensity of BiOCl by a factor of 2.1 times for carrier dynamics promotion, but also improves Cl – oxidation against H 2 O oxidation. An RCS production rate of 0.23 mg/L min −1 is realized over carbon-doped BiOCl (C-BiOCl) through the accelerated interaction between lattice and environmental Cl – , which is twice that of the undoped BiOCl (0.11 mg/L min −1 ). The relation between IEF intensity and RCS generation rate over C-BiOCl manifests a correlation coefficient of 0.96. Effective NH 4 + -N degradation with N 2 selectivity of >99% is validated. The system is competent in dealing with saline NH 4 + -N wastewater with a wide range of NH 4 + -N (20∼200 mg N/L) and NaCl (6∼10 g/L) concentrations. In the treatment of realistic landfill leachate (884 mg N/L NH 4 + -N), C-BiOCl displays a photocatalytic NH 4 + -N removal efficiency of up to 95.6% while maintaining the NO 2 − -N (∼2 mg N/L) and NO 3 − -N (∼40 mg N/L) levels. This system provided an interesting and innovative idea for wastewater self-purification.
研究领域:
环境科学
·
废水处理
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Si-Yu Duan,Xue Chen,Huang Huang,Xin Yang,Xin Lu
The formation of nitrogenous disinfection byproducts (N-DBPs) occurs in chloraminated water in drinking water distribution systems and may be affected by metal pipe materials and their corrosion products. The effect of copper corrosion products, including Cu 2+ , CuO, and Cu 2 O, on the formation of dichloroacetonitrile (DCAN) and dichloroacetamide (DCAcAm) was investigated during chloramination of natural organic matter (NOM), model precursors (carboxylic acids and amino acids), and real water samples. Copper corrosion products enhanced DCAN and DCAcAm formation during chloramination of NOM by 33%–72% and 11%–80%, respectively. Addition of 15 N-labeled monochloramine showed that the copper corrosion products primarily enhanced the formation of DCAN using organic nitrogen and monochloramine as nitrogen sources, and the formation of DCAcAm using monochloramine as the nitrogen source, but had a limited impact on the formation of DCAcAm using organic nitrogen as the nitrogen source. A distinct N-DBP formation pathway in the presence of Cu 2+ and CuO was observed using tyrosine as a model compound, which included the formation of 1,4-benzoquinone as a dominant intermediate. On reaction with monochloramine, the 1,4-benzoquinone greatly contributed to enhancement of DCAN and DCAcAm formation using monochloramine as the nitrogen source. During chloramination of real water samples, Cu 2+ and CuO enhanced DCAN formation by 9–40% and DCAcAm formation by 16–33%. This study increases our knowledge of copper catalyzed DCAN and DCAcAm formation in copper pipes, which will be meaningful for water safety in distribution systems using chloramine disinfection.
研究领域:
环境科学
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公共卫生
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF FOOD SCIENCE
·
2021
·Vol. 86
·期 12
·5495-5502
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IF 3.167
Liangting Shao,Yue Qin,Xinglian Xu,Huhu Wang
Sodium hypochlorite (NaClO) has been widely used at 100 ppm concentration during poultry slaughter to reduce carcass microorganism loads. However, its use in poultry processing is restricted owing to the potential risks of disinfection by-products (DBPs) that can be produced by the reaction of NaClO with poultry meat components. This study assessed whether dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), as primary DBP representatives, were produced when NaClO was used as a disinfectant in various methods during broiler prechilling. Headspace gas chromatography-mass spectrometry for the quantitative determination of DCAA and TCAA in 180 prechilling water samples and 30 broiler meat samples, obtained from large standard slaughterhouses equipped with an online monitoring system to control the NaClO concentration between 50 and 100 ppm, showed that neither DCAA nor TCAA were detected. In simulation assays, haloacetic acids (HAAs) were not detected when the concentration of the NaClO solution was less than 200 ppm with low frequency addition; however, more than 0.1 mg/L of DCAA and TCAA were detected on applying 200, 300, 400, 500, and 1000 ppm NaClO at high frequency. These findings indicated that adding high concentrations of NaClO and frequently adding low levels pose a potential risk of DBP formation. This investigation provides a basis for the establishment of food risk and the scientific use of NaClO in poultry processing, and contributes to the evaluation of DBPs in poultry slaughter. Practical Application This study confirmed the occurrences of DCAA and TCAA during broiler chilling processing, indicating that formation of HAAs in simulation systems was correlated with NaClO levels and validated the absence of DCAA and TCAA with less than 200 ppm, providing a basic study for food safety standards and regulations on the disinfectants used in food processing.
研究领域:
食品安全
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环境科学
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食品科学
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Jun Hu,Zhiyong Huang,Jianming Yu
In this study, Fe/Fe 3 O 4 mixture was first applied as an additive to achieve the highly-effective mechanochemical destruction (MCD) of two halogenated organic pollutants (HOPs), hexachloroethane (HCE) and hexachlorobenzene (HCB). The MCD of HCE was more effective than that of HCB in virtue of the lower dissociation energy of C Cl bond. The MCD of HOPs occurred mainly via the reduction by Fe, Fe 3 O 4 and Fe/Fe 3 O 4 . The oxidation of Fe 3 O 4 and reduction of FeO (formed on account of the oxidation of Fe by oxygen-containing species) may also contribute to the HOP destruction. Fe/Fe 3 O 4 mixture exhibited a higher dechlorination rate (DR) than other three effective additives (i.e., Fe/SiO 2 , Al/Al 2 O 3 and Mg/Al 2 O 3 mixture), owing to the electrical property of Fe 3 O 4 and its electron transfer with Fe. The HOP destruction was significantly impacted by the mass fraction of Fe 3 O 4 (MF mag ) and achieved the maximum level with an MF mag of 70%. The DR of HOPs in the atmosphere of air was higher than those of pure oxygen and nitrogen because of the oxygen vacancy in Fe 3 O 4 and oxidation of Fe. The presence of water dramatically inhibited the HOP destruction due to the decrease of collision energy and its competition for the active sites in both Fe and Fe 3 O 4 . As expected, the DR of HOPs increased with rotation speed, and the mass ratio of ball to reactant and additive to pollutant. The analysis of intermediates indicates that HCB destruction was mainly via dechlorination and polymerization, while HCl cleavage also played an important role in HCE destruction. The results demonstrate that Fe/Fe 3 O 4 mixture is a suitable additive for MCD process.
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Peipei Gao,Longfei Tang,Zichao Hu,Yue Sheng,Weitong Pan,Lu Ding,Xueli Chen,Fuchen Wang
To reduce the pollution during the pyrolysis recovery of chlorine-containing plastic waste from different sources, effects of the interaction between different plastics and polyvinyl chloride (PVC) on the transformation of chlorine at low temperature were investigated by thermogravimetry-Fourier transform infrared (TG-FTIR) and fixed-bed pyrolysis experiments. Results showed that the proportions of chlorine in chars were all <0.04 %, indicating that almost all chlorine was released after pyrolysis. However, the chlorine forms in volatiles were significantly changed with mixing different plastics. HCl production was significantly inhibited due to the addition of other plastics, while the organic chlorinated compounds (OCCs) formation was promoted, which increased the distribution of chlorine in liquid products. During PVC pyrolysis, chlorine was mainly distributed in gas (93.09 %) in the form of HCl, only a small amount of aliphatic chlorides were generated and distributed in liquid (6.89 %). After the addition of polystyrene (PS), polyethylene (PE) and polyethylene terephthalate (PET), the chlorine distribution in liquid increased to 8.86 %, 11.98 % and 25.99 %, respectively. The formation of OCCs was significantly affected by the difference in thermochemical reaction characteristics of plastics. Specifically, the production of aromatic chlorides was promoted by PS, while the generation of aliphatic chlorides and aromatic chloroesters was significantly promoted by PE and PET, respectively. Therefore, the release form of chlorine could be significantly altered by the interaction between PVC and other waste plastics, which provides a reference for the regulation of chlorine-containing pollutants in the recovery and utilization of plastic waste.
研究领域:
環境科學
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化學工程
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2013
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IF 3.258
Yan Xu,Yan He,Xiaoli Feng,Luyi Liang,Jianming Xu,Philip C. Brookes,Jianjun Wu
A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils.
研究领域:
环境微生物学
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生物修复
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土壤科学
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产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
·
IF 7.632
Ying Li,Peng Liu,Cong Ma,Na Zhang,Xiaoqin Shang,Liming Wang,Fengwei Xie
As high-amylose starch (HAS) has a higher content of linearly structured chains than other types of starch, it is more scientifically interesting to realize enhanced properties or new functions for food and materials applications. However, the full dissolution of the compact granule structure of HAS is challenging under moderate conditions, which limits its applications. Here, we have revealed that the granule structure of HAS can be easily destructed by certain concentrations of acidic ZnCl2, neutral MgCl2, and alkaline CaCl2 solutions (43, 34, and 31 wt %, respectively) at a moderate temperature (under 50 °C). The ZnCl2 and CaCl2 solutions resulted in complete dissolution of HAS granules, whereas small amounts of HAS granule remnants still existed in the MgCl2 solution. The regenerated starch from the CaCl2 solution was completely amorphous, that from the ZnCl2 solution only presented a weak peak at 17°, and that from the MgCl2 solution contained V-type crystallites. No new reflections were found on the FTIR spectra indicating that all these three chloride solutions can be considered as a nonderivatizing solvent for starch. In all the three cases, nanoparticles were formed in the regenerated starch, which could be due to the aggregation of starch chains or their complexation with the metal cation. In addition, their water absorption ratio was 1.5 to 3 times that of the control (treated in water).
研究领域:
食品科学
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材料科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）