Chemical Engineering and Processing-Process Intensification
·
2024
·
IF 3.8
Zifei Yan,Grace Dai Zhen Lee,Jian Deng,Guangsheng Luo
The synthesis of terminal epoxides, which are vital components in pharmaceuticals and resins, often involves dehydrochlorination of β-chlorohydrins. Although intrinsic kinetics indicate that the dehydrochlorination reaction in the presence of sodium hydroxide could be very rapid, the practical implementation could always be hindered by long reaction time and low conversion rate. Extended contact between the product and the alkaline solution can lead to hydrolysis of the epoxy group, thus necessitating the process intensification to realize higher production efficiency and selectivity. Here, by characterizing thermodynamic equilibrium data and in-situ recording of the reaction that proceeded in a constant interphase reactor, the heterogeneous dehydrochlorination is demonstrated to occur primarily in the organic phase, and the overall reaction rate depends on the equilibrium concentration of sodium alkoxides. This finding, which is fundamentally different from the traditional view that chlorohydrin is first dissolved in the aqueous phase and then reacts with NaOH, leads us to use inert alcohols to assist in the extraction of NaOH. Based on this method, the reaction time can be reduced over 80 % both in batch and continuous reactors. Besides, the method is demonstrated to be effective in the dehydrochlorination of five different long-chain β-chlorohydrins.
研究领域:
化学工程
·
有机合成
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jie Ma,Linhui Lei,Zhiwei Gong,Zongping Wang,Hui Liu,Guanghao Chen,Gang Guo
The efficacy of in-situ bioremediation of chlorinated ethenes (CEs)-contaminated groundwater is heavily contingent upon the provision of exogenous electron donors to facilitate reductive dechlorination by dechlorinating bacteria. Nonetheless, methanogenic archaea have been reported to engender competition for the limited electron donor supply, thereby diminishing dechlorination efficiency. This study proposes a novel strategy to enhance reductive dechlorination by reducing the particle size of polyhydroxyalkanoate (PHA) to the micrometer scale, thereby inhibiting methanogenic competition for electron donors. The results demonstrate that trichloroethylene (TCE) biodegradation efficiency peaked at a PHA particle size of 500 μm, significantly surpassing the efficiency observed in groups with particle sizes of 50 and 2000 μm. Furthermore, the electron utilization efficiency of dechlorinating bacteria (represented by Geobacter , Dehalobacter , Anaerolinea , etc in this study) was as high as 94.82 % over methanogenic archaea (represented by Methanobacterium ) in the 500 μm group. Mechanistic analyses revealed that the 500 μm PHA particles activated dark oxygen, leading to the generation of reactive oxygen species that decreased the abundance of the methanogenic functional gene McrA and increased the abundance of dechlorinating functional gene TceA relative to the total microbial genome gene (in terms of 16S rRNA). In contrast, PHA particles of 50 μm exhibited lower TCE biodegradation efficiency due to particle aggregation, while particles of 2000 μm exhibited reduced efficiency due to lower specific surface area. This study moves a step for the in-situ microbial remediation of CEs-contaminated groundwater.
研究领域:
环境科学
·
生物修复
·
微生物学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Yu-qiong Gao,Yan-yan Rao,Han Ning,Ju-xiang Chen,Qian Zeng,Fu-xiang Tian,Nai-yun Gao
The degradation of diclofenac (DCF), a commonly used nonsteroidal anti-inflammatory drug, by Fe 2+ /chlorine and Fe 2+ /PMS processes was comparatively investigated. The influencing factors of pH, Fe 2+ and oxidant dosage on DCF degradation efficiency were evaluated and optimized. Typically, with an initial solution pH of 5, an Fe 2+ dosage of 70 μM, and a chlorine or PMS dosage of 70 μM, the degradation efficiency of DCF using the Fe 2+ /chlorine and Fe 2+ /PMS processes reached 94.2% and 79.7%, respectively, within 10 min. Quenching tests indicated the coexistence of •OH and RCS in the Fe 2+ /chlorine system, and both SO 4 ●– and •OH were identified in the Fe 2+ /PMS system. In addition, Fe(IV) was also identified to participate in DCF degradation in two systems based on the oxidation of PMSO to PMSO 2 . The degradation products and pathways of DCF were elucidated by LC/TOF/MS analysis and DFT calculations. It was assumed that the degradation pathway of DCF involves hydroxylation, dechlorination, decarboxylation, cleavage of the C-N bond, and chlorine substitution. In addition, trichloromethane (TCM), dichloroacetaldehyde (DCAL), dichloroacetonitrile (DCAN) and trichloronitromethane (TCNM) were also detected in the Fe 2+ /chlorine process, and these chlorinated DBPs initially increased and then decreased with prolonged reaction time, indicating that Fe 2+ /chlorine is capable of controlling DBPs formation. Finally, the acute and chronic toxicity of DCF and its degradation products were evaluated by the ECOSAR program.
研究领域:
环境科学
·
化学工程
·
毒理学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2021
·
IF 9.028
Li Gong,Xiaojiang Qiu,Dong Cheng,Yao Hu,Zaizhi Zhang,Qunsen Yuan,Dezhi Yang,Chengshuai Liu,Liyuan Liang,Feng He
Sulfidated zero-valent iron (S-ZVI) enhances the degradation of chlorinated hydrocarbon (CHC) in contaminated groundwater. Despite numerous studies of S-ZVI, a versatile strategy to improve its dechlorination kinetics, electron efficiency (εe), and dechlorination capacity is still needed. Here, we used heteroatom incorporation of N(C) and S by ball-milling of microscale ZVI with melamine and sulfur via nitridation and sulfidation to synthesize S-N(C)-mZVIbm particles that contain reactive Fe-NX(C) and FeS species. Sulfidation and nitridation synergistically increased the trichloroethene (TCE) dechlorination rate, with reaction constants kSA of 2.98 × 10–2 L·h–1·m–2 by S-N(C)-mZVIbm, compared to 1.77 × 10–3 and 8.15 × 10–5 L·h–1·m–2 by S-mZVIbm and N(C)-mZVIbm, respectively. Data show that sulfidation suppressed the reductive dissociation of N(C) from S-N(C)-mZVIbm, which stabilized the reactive Fe-NX(C) and reserved electrons for TCE dechlorination. In addition to lowering H2 production, S-N(C)-mZVIbm dechlorinated TCE to less reduced products (e.g., acetylene), contributing to the material’s higher εe and dechlorination capacity. This synergistic effect on TCE degradation can be extended to other recalcitrant CHCs (e.g., chloroform) in both deionized and groundwater. This multiheteroatom incorporation approach to optimize ZVI for groundwater remediation provides a basis for further advances in reactive material synthesis.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2020
·Vol. 167
·期 14
·142505
·
IF 3.721
Wei Han,Wenjuan Wang,Mei Li,Yangyang Meng,Wenjing Ji,Yang Sun
To recover Gd from LiCl-KCl eutectic, the coreduction mechanism of Gd(III) with Pb(II) was investigated using electrochemical methods. The formation potentials related to the formation of three Gd-Pb intermetallics were detected by cyclic voltammetry, square wave voltammetry and chronopotentiometry, and the formation mechanism of Gd-Pb compounds could be described as xPb(II) + 2xe− = xPb. Meanwhile, the electroreduction of Gd on liquid Pb electrode was explored. The diffusion coefficient of Gd metal in liquid metallic Pb was determined by anodic chronopotentiometry. The kinetic parameters of Gd(III)/Gd(in Pb) couple in the temperature range from 723 K to 873 K were determined employing linear polarization (LP) method. Based on the relationship of exchange current density and temperature, the reaction activation energy was estimated to be 23.17 kJ mol−1. In addition, the recovery of Gd from molten salts was performed assisted by liquid Pb electrode by constant potential electrolysis (CPE) and constant current electrolysis (CCE). The products characterized using XRD, SEM with EDS are comprised of GdPb3 and Pb phases. The concentration change of Gd during CCE process was monitored by ICP-AES, and the recovery rate was estimated. The results showed that Gd concentration decreased and recovery rate increased with the duration.
研究领域:
材料科学
·
电化学工程
✓ 已验证
DOI
高影响因子
Plants-Basel
·
2025
·Vol. 14
·期 9
·1353
·
IF 4.1
Yanan Ma,Liangfang Wang,Zuozeng Cao,Hui Wang,Fu Wang,Wenying Zhu
Tomato yellow leaf curl disease (TYLCD) significantly affects tomato yield. The jasmonic acid (JA) pathway is crucial in the defence response of plants; however, its role in plant resistance to TYLCD remains undefined. In production, CCC (chlorocholine chloride) is often used to cultivate strong seedlings to enhance seedling vitality and improve stress resistance. However, the mechanism through which CCC enhances disease resistance in tomatoes remains unclear. In this study, tomato seedlings were exogenously sprayed with 300 mg/L CCC before and after inoculation with tomato yellow leaf curl virus (TYLCV). The results indicated that no significant tomato yellow virus disease phenotype was observed in tomato seedlings after spraying with CCC and subsequent inoculation with the virus. Spraying CCC on seedlings inoculated with the virus and exhibiting typical phenotypes can significantly alleviate the yellowing and curling symptoms of new leaves and improve photosynthesis-related indicators in tomato plants. The detection of virus copy numbers within the plants revealed that the virus copy numbers in plants treated with CCC were significantly lower than those in the control group. Transcriptomic analysis revealed that, after spraying CCC, the key enzyme genesAOS2andAOCin the JA synthesis pathway in tomatoes were significantly upregulated, whereas the expressions ofJAZ2andMYC2genes, which negatively regulate JA synthesis, were significantly downregulated. In the stable state, JAZ proteins interact withMYC2and inhibit its transcriptional activity ofMYC2. Tomatoes overexpressingMYC2andJAZ2exhibit a significant decrease in TYLCD resistance. These results indicated that exogenous spraying CCC affected the expression of genes such asMYC2andJAZ2, and then regulated JA pathway, increased the endogenous JA content in plants, and enhanced the disease resistance of tomato plants to TYLCD. This study provides a scientific reference for effectively preventing and controlling TYLCD in tomato production and reducing the influence of TYLCD on tomato yield and quality.
研究领域:
植物学
·
分子生物学
·
病害防治
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NANOTECHNOLOGY
·
2022
·Vol. 33
·期 21
·210001
·
IF 3.953
Yiwen Chen,Junguo He,Peigen Jiang,Heliang Pang,Xuhui Hu,Jie Zhang,Wenjing Zhang
The growing chloramphenicol (CAP) in wastewater brought a serious threat to the activity of activated sludge and the spread of antibiotics resistance bacteria. In this study, a highly ordered nanoporous Co3O4 layer on Co foil through anodization was prepared as cathode for nitro-group reduction and electrodeposited with Pd particles for dechlorination to reduce CAP completely. After 3 h treatment, almost 100% of CAP was reduced. Co2+ ions in Co3O4 served as catalytic sites for electrons transfer to CAP through a redox circle Co2+–Co3+–Co2+, which triggered nitro-group reduction at first. With the presence of Pd particles, more atomic H* were generated for dechlorination, which increased 22% of reduction efficiency after 3 h treatment. Therefore, a better capacity was achieved by Pd/Co3O4 cathode (K = 0.0245 min−1, K is reaction constant) than by other cathodes such as Fe/Co3O4 (K = 0.0182 min−1), Cu/Co3O4 (K = 0.0164 min−1), and pure Co3O4 (K = 0.0106 min−1). From the proposed reaction pathway, the ultimate product was carbonyl-reduced AM (dechlorinated aromatic amine product of CAP) without antibacterial activity, which demonstrated this cathodic technology was a feasible way for wastewater pre-treatment.
研究领域:
环境科学
·
化学工程
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2018
·
IF 6.434
Xiang Li,Minghua Zhou,Yuwei Pan
2,4-dichlorophenoxyacetic acid (2,4-D) is one of the most applicable herbicides in the world, its residue in aquatic environment threatens the human health and ecosystems. In this study, for the first time, inexpensive Fe-C after pre-magnetization (Pre-Fe-C) was used as the heterogeneous catalyst to activate persulfate (PS) for 2,4-D degradation, proving that Pre-Fe-C could significantly improve the degradation and dechlorination. The results indicated the stability and reusability of Pre-Fe-C were much better than pre-magnetization Fe 0 (Pre-Fe 0 ), while the leaching iron ion was lower, indicating that using Pre-Fe-C not only reduced the post-treatment cost, but also enhanced the removal and dechlorination efficiency of 2,4-D. Several important parameters including initial pH, Fe-C dosage, PS concentration affecting 2,4-D degradation and dechlorination by Pre-Fe-C/PS were investigated and compared with that of Fe-C/PS, observing a 1.2–2.7 fold enhancement in the degradation rate of 2,4-D. The Fe-C and Pre-Fe-C were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and SEM-EDX-mapping, suggesting that the content of Fe and O changed more obviously after magnetization. The degradation intermediates, such as chloroquinol, 2-chlorophenol, were identified by a gas chromatography mass spectrometry (GC/MS) and an ion chromatography (IC), and a possible degradation pathway was proposed.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Journal of Water Process Engineering
·
2025
·
IF 6.7
Chengzhi Zhou,Zhen Wang,Haoran Wang,Yanlong Sun,Lei Yang,Hangyang Feng,Liguo Shen,Xia Tian,Junfeng Niu
In the present work, the electrochemical degradation of artificial sweetener alitame was performed by using two-dimensional plate anode and three-dimensional porous membrane anode. The results show that the alitame degradation rate increased about 10 times and energy consumption reduced 10 times, when the plate anode was replaced by porous membrane anode. The degradation rate constant of alitame was 0.305 min −1 and the energy consumption was 0.27 Wh L −1 using membrane anode at current density of 2 mA cm −2 . The presence of NO 3 − and HCO 3 − inhibited the alitame degradation, while Cl − improved the alitame removal significantly. The promotion effect was mainly ascribed to free chlorine specie in high chlorine content, and the effect in low chlorine content was attributed to ·OH, chlorine radical and free chlorine specie together. Twenty-six degradation products including three chlorinated intermediates were identified in the presence of chloridion. The degradation process mainly included hydroxylation, dehydrogenation, sulfur-replaced reaction, dehydration condensation and chlorinated reaction. Toxicity analysis results show that potential risks in developmental toxicity and mutagenicity should be not ignored when chloridion exists. These results demonstrate that electrocatalysis with three-dimensional membrane anode exhibits high efficiency in removing artificial sweeteners especially in a chlorine environment.
研究领域:
环境科学
·
电化学
·
毒理学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·Vol. 31
·期 30
·42921-42930
·
IF 0
Ye Miaomiao,Luo Ziyi,Jin Wen,Wang Xingyuan,Zhang Tuqiao,Liu Xiaowei
The viewpoints on whether high concentrations of chloride ion (Cl − ) promote or inhibit the oxidation activity of activated persulfates are still inconclusive. Furthermore, the degradation of organic pollutants by the persulfates in the presence of high Cl − concentrations without any activation medium has not yet been studied. In this work, the efficiency and mechanism of degradation of organic pollutants such as carbamazepine (CBZ), sulfadiazine (SDZ), and phenol (PN) by Cl − -activated PMS (denoted as Cl − /PMS) were investigated. Results showed that Cl − could effectively activate PMS for the complete removal of CBZ, SDZ, and PN with reaction kinetic constants of 0.4516 min −1 , 0.01753 min −1 , and 0.06805 min −1 , respectively. Parameters such as PMS dose, Cl − concentration, solution pH, and initial concentrations of organic pollutants that affect the degradation efficiencies of the Cl − /PMS process were optimized. Unlike conventional activated persulfates, it was confirmed that the free chlorine was the main active species in the Cl − /PMS process. Finally, the degradation by-products of CBZ and SDZ as well as their toxicity were detected, and a possible degradation pathway for CBZ and SDZ was proposed. Though higher toxic chlorinated by-products were generated, the Cl − /PMS process was still an efficient oxidation method for the removal of organic pollutants in aqueous solutions which contain high concentrations of Cl − .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Sheng-Nan Li,Shu-Xian Zheng,Zi-Xuan Zheng,Yu Ling,Hai-Ming Wu,Hai Liu
The widespread use of chlorination prompts the selection of chlorine-resistant bacteria in drinking water, posing a great threat to public health. Herein, according to sequential electrochemical oxidation/reduction (Ox/Red) processes with a flow-through mode, electrochemical devices (ED) with sequential Ox-Red, Red-Ox and Ox-Red-Ox processes were coupled with chlorination (AC) to evaluate their synergistic effects and mechanisms for inactivation of chlorine-resistant bacteria in drinking water. ED/AC enabled ∼ 3.0 log of synergistic effect and ∼ 2.5 times lower energy consumption for inactivation of various chlorine-sensitive/-resistant bacteria and gram-positive/-negative bacteria in DI and tap waters. Especially, ED/AC with Ox-Red-Ox device exhibited the best disinfection performance with achieving over 6.7 log inactivation of Bacillus cereus at 4.0 V and 0.5 mg/L-Cl 2 as compared with ED alone (∼1.25 log) and AC (∼2.67 log) disinfection. The electrochemical oxidation on Ti 4 O 7 -based anode promoted the generation of free chlorine radicals and H + ions, which was accompanied with the formation of neutral HClO molecules. Characterizations of SEM and flow cytometer suggested that oxidative species of neutral HClO molecules and free chlorine radicals enhanced the bacterial inactivation via severe damages of cell structures. This work provided a promising strategy via coupling electrochemical oxidation and chlorination for eliminating chlorine-resistant bacteria in drinking water.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zheng Li,Jiehao Xie,Zipin Peng,Zhuo Ma,Yihui Li,Xingkun Chen,Yuan Tan,Wenshao Yang,Yunjie Ding
4-Chlorophenol (4-CP) is a pervasive environmental pollutant commonly found in wastewater and groundwater, posing great risks to both human health and the ecosystem. Catalytic hydrodechlorination (HDC) of 4-CP by utilizing hydrogen (H 2 ) as a reductant has emerged to be an efficient and sustainable way to treat pollutant water. This study focuses on the development of an efficient and stable Pd-based catalyst for the catalytic HDC of 4-CP. By incorporating an appropriate amount of Ni into Al 2 O 3 support, a NiAl 2 O 4 (NA) spinel was synthesized, enhancing the interaction between Pd and the support, leading to precise control over Pd species and oxygen vacancies. The tailored properties of the Pd/NA-1 catalyst result from meticulous adjustment of the Pd 2+ /Pd 0 ratio and oxygen vacancies, which promotes electron transfer from Pd to Ni within the NiAl 2 O 4 spinel. In comparison to the Pd/Al 2 O 3 catalyst, the Pd/NA-1 catalyst exhibits exceptional stability, with continuous operation for over 120 h without deactivation. Comprehensive characterization analyses indicate that the Pd/NA-1 catalyst effectively prevented the aggregation of Pd nanoparticles, maintaining the Pd 2+ /Pd 0 ratio at 1, which is crucial for its superior stability. This work provides valuable insights into the development of Pd-based catalysts for HDC reactions, highlighting the potential use of Pd/NA-1 catalysts in treating hazardous pollutants like 4-CP in waste systems.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）