JOURNAL OF FOOD SCIENCE
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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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产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CHEMISTRY
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2011
·Vol. 29
·期 4
·778-782
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IF 0.773
Haining Shi,Zonghua Wang,Hui Wang,Rui Zhao,Mingyu Ding
An anion-exchange chromatography method combined solid phase extraction (SPE) was developed for the simultaneous analysis of glycolate acid (GL), monochloroacetic acid (MCA) and dichloroacetic acid (DCA) in synthetical betaine products. The analytes and unknown anionic impurities were well separated on a Metrosep A supp5 anion-exchange column (150 mm×4 mm) with 2.0 mmol/L Na 2 CO 3 +2.0 mmol/L NaHCO 3 solution as eluent. Suppressed conductivity detection was used. A strong cation exchange (SCX) solid phase extraction (SPE) cartridge was used to reduce the concentration of matrix betaine and a Cleanert IC-Ag pretreatment cartridge was used to remove high Cl − concentration. The detection limits of GL, MCA and DCA were 0.09, 0.017 and 0.05 µg/L, respectively. The relative standard deviations (RSDs) of the retention times and peak areas were less than 0.09% and 0.49%, respectively. The recoveries of the three analytes were between 90.6% and 100.8%. The analytical results showed that GL and DCA were present in high concentration and no MCA was found when the proposed ion chromatography method was applied to three synthetical betaine samples. The proposed method is simple, sensitive and timesaving, and is also suitable for routine analysis in quality control of synthetical betaine products.
研究领域:
分析化学
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药物质量控制
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分离科学
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环境分析
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食品化学
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DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2022
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IF 6.633
Wang Jun,Zhu Tianlong,Deng Ziwen,Liu Haicheng,Huang Chunxiang,Li Na,Sun Xueni,Shao Hui,Qi Lv
Isobaric vapour-liquid equilibrium (VLE) data for binary systems containing methyl chloroacetate (MC) + methyl 2-chloropropionate (M2C), MC + methyl dichloroacetate (MDC), and M2C + MDC at 101.33 kPa and the saturated vapour pressure data of these components were measured by using a modified Othmer still. The VLE data showed that these binary systems were all slightly positive deviation solutions compared with the ideal system. Herington area and point tests were used to confirm the thermodynamic consistency for these binary systems, and the results showed good thermodynamic consistency. The interaction energy ( E inter ) between these components was calculated by molecular simulation to explain the normal boiling point and VLE behavior. The simulation results showed weak hydrogen bonds between these chlorinated esters. In addition, the binary VLE experimental data were correlated by the Wilson, NRTL, and UNIQAC models. The correlated results agreed well with the experimental values.
研究领域:
化学工程
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物理化学
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DOI
高影响因子
Membranes
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2021
·Vol. 11
·期 9
·705
·
IF 4.106
Kaifeng Gu,Sichen Pang,Yong Zhou,Congjie Gao
Nanofiltration (NF) is a separation technology with broad application prospects. Membrane fouling is an important bottleneck-restricting technology development. In the past, we prepared a positively charged polyethyleneimine/trimesic acid (PEI/TMA) NF membrane with excellent performance. Inevitably, it also faces poor resistance to protein contamination. Improving the antifouling ability of the PEI/TMA membrane can be achieved by considering the hydrophilicity and chargeability of the membrane surface. In this work, sodium chloroacetate (ClCH2COONa) is used as a modifier and is grafted onto the membrane surface. Additionally, 0.5% ClCH2COONa and 10 h modification time are the best conditions. Compared with the original membrane (M0, 17.2 L m−2h−1), the initial flux of the modified membrane (M0-e, 30 L m−2h−1) was effectively increased. After filtering the bovine albumin (BSA) solution, the original membrane flux dropped by 47% and the modified membrane dropped by 6.2%. The modification greatly improved the antipollution performance of the PEI/TMA membrane.Keywords:nanofiltration;sodium chloroacetate;modification;antipollution performance
研究领域:
材料科学
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环境工程
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Qiang Zhang,Xiaolei Wang,Nannan Wu,Changyin Zhu,Wenxiu Qin,Danyu Huang,Dongmei Zhou
The degradation of haloacetic acids (HAAs) in aqueous environments poses a challenge due to their oxidative resistance. Given that HAAs are highly carcinogenic disinfection byproducts, it is imperative to develop effective degradation methods to reduce their potential health risk. In this study, we found that only 27.2% of 200 μM trichloroacetic acid (TCA) was removed in the UV-activated persulfate (PS) system after 2 h, while complete removal was achieved with the addition of 15 mM formic acid (FA). The main products of TCA degradation were dichloroacetic acid and monochloroacetic acid. Results from free radical quenching experiments and electron paramagnetic resonance spectroscopy analyses indicated that reductive carbon dioxide radical (CO 2 •− ) was the main active species responsible for TCA reduction. Oxidative radicals (i.e., SO 4 •− and • OH) generated from PS activation reacted with FA to form CO 2 •− , efficiently degrading TCA. The effects of PS and FA concentrations, solution pH, anions (e.g., Cl − , SO 4 2− , and HCO 3 − ), and small organic molecules (e.g., methanol, ethanol, and acetic acid) on degradation efficiency were examined. Overall, this study proposes a simple and efficient method to improve the degradation efficiency of HAAs in the UV/PS system and provides new insights into the advanced reduction processes used for water treatments.
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
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2011
·
IF 2.733
Ying Hua Xu,Hong Zhang,Cheng Pu Chu,Chun An Ma
Chloroacetic acids (CAAs, including trichloroacetic acid, dichloroacetic acid and monochloroacetic acid) are byproducts formed upon the addition of chlorine to water for disinfection purpose and they pose a potential human health risk. To catalyze the dechlorination of CAAs, an activated silver electrode was prepared by an oxidation–reduction cycle process. Surface structure and roughness factor of the activated silver electrode and its catalytic activity (including stability) towards the dechlorination of CAAs in aqueous solutions of different pH were studied by SEM, underpotential deposition (UPD) method, cyclic voltammetry (CV) and controlled-current electrolysis, respectively. Experimental evidence is presented that the activated silver electrode, having a porous surface with a roughness factor of approx. 63.9, is an excellent electrocatalytic material for direct dechlorination of CAAs and the complete dechlorination of trichloroacetic acid to safe acetic acid with excellent current efficiency (near 95%) can be successfully achieved by using this peculiar electrode in alkaline aqueous solutions. The reduction of trichloroacetic acid in a stepwise dechlorination fashion was suggested and trichloroacetic acid (TCAA) → dichloroacetic acid (DCAA) → monochloroacetic acid (MCAA) → acetic acid (AA) probably is the main reductive reaction route independent of pH.
研究领域:
环境科学
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电化学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
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2022
·
IF 5.723
Jinghua Wang,Hongyou Cui,Jiangang Wang,Zhihe Li,Ming Wang,Weiming Yi
A novel approach is reported for efficient esterifying low molecular acids with alcohols in molten salt hydrate (MSH) without additional catalyst. A series of MSHs (LiCl, CaCl 2 , ZnCl 2 and ZnBr 2 ) were evaluated for catalytic esterification of chloroacetic acid (CA) with methanol to methyl chloroacetate (MC). The effects of coordination water number also examined. It was found that appropriate coordination water number not only can promote the protonation of the reactant acids, but also enhance the activity of the protons as well as esterification equilibrium towards ester formation. A MC yield of 98.1% with concentration of 92.1% in the organic-phase could be readily achieved after reacting at 80 °C for 2.0 h in CaCl 2 ·4H 2 O. MSH also demonstrated excellent performance in esterification of other acids (acetic, mercaptoacetic, propionic, n -butyric and levulinic acids) with alcohols (ethanol, n-propanol and n-butanol). After removing portion of the water from MSH, it can be reused without any difficulty. The promotion effects of MSH on the esterification reaction can be categorized to three aspects: (1) accelerating the reaction rate due to the enhanced protonation of the reactant acids and reduction in the hydration degree of the protons; (2) facilitating phase-splitting by virtue of the poor solubility in MSH and thus expelling the formed esters into organic-phase, as a result, boosting up esterification conversions; and (3) promoting the esterification reaction equilibrium owing to the strong hygroscopicity of MSH. Economic analysis shows, compared with the conventional esterification of CA with ethanol, in which organic solvents is used as the water-carrying agent, that esterification in MSH could not only accelerate the reaction rate and strengthen the equilibrium conversion, but also save energy input.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2020
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IF 9.038
Lei Wang,Yi Chen,Baiyang Chen,Jie Yang
Upon ultraviolet (UV) irradiation, aqueous contaminants may undergo direct and/or indirect photolysis. Direct photolysis refers to transformation of contaminants by UV photon, and indirect photolysis refers to degradation of contaminants by UV-induced reactive species in the presence of photosensitizers. Because hydroxyl radical (•OH) was unexpectedly observed during chloroacetic acids photolysis without using photosensitizer, a question arises regarding whether direct photolysis-induced indirect photolysis (DPIP) was present and how it originated and evolved along the process. To answer these questions, this study employed multiple different yet complementary •OH detection approaches (i.e., probe, scavenger, electron paramagnetic resonance, and hydroxylation products) to prove the presence and role of •OH. Given that hydrogen peroxide (H 2 O 2 ) was produced only in oxygenated water but not in deoxygenated water, we revealed that •OH was mainly generated by reduced oxygen. Meanwhile, several photolysis products like formate, glycolic acid, and glyoxylic acid were able to yield H 2 O 2 too, suggesting that they can all trigger formation of •OH under 254 nm UV. In addition to evidences of DPIP phenomenon, this study is also novel in demonstrating a holistic methodology to prove and identify the presence and sources of radicals, which might help enhance understandings of UV processes.
研究领域:
环境科学
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化学
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DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Jie Yang,Yulin Zhang,Yinan Bu,Baiyang Chen,Juan Li
According to an earlier study, electrodialysis (ED) can efficiently separate most organic halogenated micropollutants from inorganic halogens (i.e., halides and oxyhalides) in water, with only a few micropollutants being poorly-recovered. To optimize the ED process and to gain in-depth knowledge of the mechanisms responsible for their low recoveries, this study designed some experiments to examine the fates and transports of three hard-to-separate organic halogen compounds. Results show that the dominant mechanism responsible for the loss of trichlorophenol (TCP) is migration and retention in the ion exchange membrane (IEM), the dominant mechanism for the loss of trichloroacetic acid (TCAA) is ion exchange with the IEM, and the dominant mechanism for the loss of trichloroacetonitrile (TCAN) is volatilization and chemical decomposition during the ED process. Optimizing specific operating conditions (e.g., sealing, voltage, and membrane type, etc.) can improve recovery of these micropollutants to 70.4–95.8% while maintaining 90.4–99.5% removal of chloride. Even though TCAN underwent hydrolysis, we recovered 82.0% chlorine from TCAN and its hydrolytic products. These results may help not only better understand the fates and transports of organic micropollutants during the ED process, but also help facilitate application of electrodialysis technique for measuring total organic halogen.
研究领域:
环境科学
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水处理技术
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DOI
高影响因子
PLoS One
·
2014
·Vol. 9
·期 4
·e92962
·
IF 3.534
Yunhai Dai,Xiaopeng Xiong,Gang Huang,Jianjun Liu,Shile Sheng,Hongjian Wang,Wenxin Qin
A unique bioenergetic feature of cancer, aerobic glycolysis is considered an attractive therapeutic target for cancer therapy. Recently, dichloroacetate (DCA), a small-molecule metabolic modulator, was shown to reverse the glycolytic phenotype, induce reactive oxygen species (ROS) generation, and trigger apoptosis in various tumor cells. In this work, the capacity of DCA to enhance Adriamycin (ADM) efficacy in hepatoma cells by modulating glucose metabolism and redox status was evaluated. Two human hepatoma (HCC-LM 3 and SMMC-7721) and a normal liver (LO 2 ) cell lines were treated with DCA or ADM alone, or in combination. Exposure of hepatoma cells to DCA/ADM combination resulted in significantly decreased cell viability and increased percentage of apoptotic cells as well as intracellular ROS levels, in comparison with treatment with DCA or ADM alone. However, simultaneous treatment with the thiol antioxidant N-acetylcysteine (NAC, 10 mmol/L) reduced the elevated ROS levels and protected hepatoma cells from the cytotoxic effects of DCA/ADM combination. L-buthionine-[S,R]-sulfoximine, an inhibitor of glutathione synthesis, enhanced hepatoma cell sensitivity to DCA/ADM combination. Interestingly, treatment with DCA/ADM combination did not significantly increase cytotoxicity in normal hepatocytes in comparison with the drugs administered individually. Finally, DCA reduced tumor growth and enhanced ADM efficacy on HCC-LM 3 hepatoma in mice. Overall, our data suggest that DCA enhances ADM cytotoxicity in hepatoma cells by increasing intracellular ROS levels and provide a strong biochemical rationale for the use of DCA in combination with ADM for treatment of hepatoma.
研究领域:
肿瘤学
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生物化学
·
药理学
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Xiaoyan Ma,Sinong Huang,Yuhong Jin,Hang Jiang,Liangjie Tang,Yifei Wu,Yongjiong Ni,Shijun Zhu,Xueyan Li,Andrea M. Dietrich
Haloacetic acids (HAAs) are ubiquitously detected in drinking water and even persistent after boiling due to their stability and nonvolatility, which leads to risk exposure to human. To minimize the risk, HAAs removal through electrocatalytic reduction easily utilized in point-of-use household devices is proposed. Trichloroacetic acid (TCAA) as a typical target, was investigated using laboratory-prepared metal electrode modified with Vitamin B12 (VB12) by the drop coating method. The dechlorination performance and effects of influencing factors on the TCAA dechlorination by VB12/metal composite cathode were studied. Under the conditions of 10.0 mg VB12 loading and 7.0 mA/cm 2 current density, 92.9% TCAA removal efficiency was achieved within 5 h at 25 °C in neutral water solution. The degradation processes followed the first-order kinetic model. The results show that VB12/iron (Fe) electrode presented the superior electrocatalytic activity than VB12/aluminium and VB12/copper. The dechlorination efficiency of TCAA was promoted by higher VB12 loadings and current density; inhibited by alkaline condition and higher initial concentration of TCAA. The synergistic effect between atomic H* and VB12 occurred during the TCAA dechlorination process through the electron transfer . The proposed pathway elucidated that TCAA was dechlorinated to form dichloroacetic acid (DCAA) and monochloroacetic acid (MCAA), with acetic acid and chloride as ultimate products. This electrocatalysis system with VB12/Fe composite electrode exhibits high reaction efficiency, targeted dehalogenation, and environmental friendliness. This work is expected to provides a new way for the removal of halogenated DBPs at the tap and the safeguard drinking water for consumers.
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
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产品关联
DOI
高影响因子
RARE METALS
·
2024
·
IF 9.6
Hu Xiao-Jie,Sun Yu-Han,Liu Ling-Yue,Mao Dan-Jun,Zheng Shou-Rong
Monochloroacetic acid (MCAA) is identified as a highly carcinogenic disinfection by-product in chlorinated drinking water. In this study, a series of CeO 2 -supported Pd catalysts (Pd/MCeO 2 ) were synthesized through one-step calcination of Pd-loaded Ce-UiO-66-BDC (Ce-MOF), and the liquid-phase catalytic hydrodechlorination of MCAA was explored using these catalysts. For comparison, Pd/CeO 2 catalysts were additionally synthesized using the conventional impregnation method. The characterization results reveal that the catalysts exhibit strong metal–support interaction, leading to high Pd dispersion and Pd n + content. Additionally, the calcination temperature significantly influences catalytic performance, with the catalyst calcined at 500 °C (Pd/MCeO 2 -500) demonstrating the highest catalytic activity and achieving complete dechlorination of MCAA within 50 min. Furthermore, it is found that the catalytic MCAA hydrodechlorination using the catalysts adheres to the Langmuir–Hinshelwood model. Accordingly, low reaction pH is favorable for the catalytic hydrodechlorination of MCAA, enhancing MCAA adsorption on the catalyst surface due to the electrostatic interaction between MCAA and the catalyst surface. Theoretical results suggest that the presence of Pd n + efficiently facilitates MCAA adsorption and C–Cl cleavage, thus significantly enhancing the liquid-phase catalytic hydrodechlorination. Graphical abstract
研究领域:
环境科学
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催化化学
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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）