APPLIED CATALYSIS A-GENERAL
·
2020
·
IF 5.006
Haodong Duan,Xiaolei Xu,Kangwei Leng,Ge Guo,Qing Yu,Xinjin Li,Yuxi Han,Jun Gao,Zhongwei Wang
The characteristics of the reaction for the preparation of dichlorophenylphosphine (DCPP) via benzene and PCl 3 in the presence of AlCl 3 were studied. Some unique characteristics were observed when a catalytic amount of AlCl 3 was used. Namely, more than one mole of DCPP was obtained per mole AlCl 3 , the reaction solution was layered, and DCPP could be directly separated. Our mechanistic study showed that benzene reacted with PCl 3 to form DCPP-AlCl 3 , and DCPP-AlCl 3 dissociated into DCPP and AlCl 3 , continuing to catalyze this reaction. This resulted in the high catalytic efficiency of AlCl 3 . The layering of the reaction solution was caused by the immiscibility of DCPP-AlCl 3 with the raw materials, greatly facilitating the dissociation process of DCPP-AlCl 3 . The formation of diphenylphosphorus chloride (DPC) was due to a continuous Friedel-Crafts reaction between DCPP and benzene. DPC cooperated with AlCl 3 to form the stable coordination compound DPC-AlCl 3 that did not dissociate and was responsible for the deactivation of AlCl 3 .
研究领域:
有机化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Jie Yu,Xiaoli Hou,Xiantao Hu,Hong Yuan,Jingyu Wang,Chuncheng Chen
Chloramphenicol (CAP) has been extensively used in the broad-spectrum antibiotic therapy so that its excessive emission has brought about serious contamination in aquatic environments. It is of great concern to find an efficient removal method and understand the transformation pathways. In this study, we developed the zero-valence iron based catalytic technique by synthesizing regular zero-valence iron microspheres (ZVI MPs), which could completely remove the CAP pollutant (20 mg L −1 ) within 15 min. When the CAP concentration increased to 50 mg L −1 , the removal efficiency achieved to 95.5% after 15 min of reaction. The chemical evolutions of iron species on the catalyst surface and changes in components of the solution demonstrated the activation of molecular oxygen and hydrogen ion by ZVI MPs. The generation of OH and H radicals as well as their contributions to CAP degradation were confirmed by electron spin resonance and trapping experiments during the reaction. Further experiments including the intermediates identification revealed a possible degradation pathway. To the best of our knowledge, the mechanism of CAP degradation by ZVI was proposed for the first time involving both reductive and oxidative transformations with a prerequisite of efficient reductive dechlorination. The complete dechlorination of CAP molecules was confirmed by the detection of inorganic Cl – concentration (0.124 mmol L −1 after reaction), which generally lowered the toxicity of the products. These findings not only provided an efficient and economic zero-valent iron technique for eliminating the antibiotic pollutants in water, but also made important contributions to better understand the removal mechanism.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2019
·
IF 3.315
Zaizheng Dong,Yimin Zhu,Yuexin Han,Peng Gao,Xiaotian Gu,Yongsheng Sun
Arsenopyrite is a typical arsenic-containing mineral, and gold is generally hosted by arsenopyrite mineral which adversely affects gold leaching. In this study, a novel environmentally friendly oxidant, chlorine dioxide (ClO 2 ), was used for the first time to efficiently oxidize arsenopyrite under acidic conditions, preventing the adverse effect of arsenopyrite on gold leaching. The addition of solid NaClO 2 to acidic arsenopyrite slurry made the oxidation of arsenopyrite feasible for practical purposes, as NaClO 2 generates ClO 2 under acidic conditions, which then oxidizes arsenopyrite. For a 400 mL sample of arsenopyrite pulp with the initial concentration of 4.07 g/L (0.025 M), the oxidation efficiencies of Fe and As in arsenopyrite reached 94.25% and 85.39%, respectively for NaClO 2 and H 2 SO 4 concentrations of 0.125 M each, under magnetic stirring for 1 h at 30 °C in a constant-temperature water bath. At the end of the reaction, both the acidity and oxidation-reduction potential of the system increased, and the ClO 2 concentration correspondingly decreased. Chemical composition analysis, X-ray diffraction analysis, particle size distribution measurements, scanning electron microscopy combined with energy dispersive spectrometer analysis, and X-ray photoelectron spectroscopy of arsenopyrite mineral ore and its oxidized residues were performed under different reaction conditions. Analysis results indicated that tiny amorphous precipitates of the oxidation by-products, such as FeAsO 4 ·7H 2 O, H 3 AsO 3 , Fe 2 (SO 4 ) 3 ·7H 2 O, and hydrated ferric oxides would cover the surface of unreacted arsenopyrite at low H 2 SO 4 concentration, which prevented the oxidation-reduction reaction from proceeding. As the concentrations of H 2 SO 4 and NaClO 2 increased, fine arsenopyrite particles were oxidized first, and ClO 2 gradually eroded the surface of the unreacted arsenopyrite minerals to form cracks, defects, and pores, until arsenopyrite was fully oxidized. ClO 2 presents several advantages: it can be easily prepared, it is a strong oxidant, and is non-polluting. Therefore, the procedure in this study is expected to be used as a novel method for preventing the effect of arsenopyrite enwrapping gold in refractory gold ores and for directly leaching gold.
研究领域:
化学工程
·
环境科学
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Xiang Li,Minghua Zhou,Yuwei Pan,Liting Xu
The abatement of chlorophenols is of great environmental importance. Though Fe 0 can activate persulfate (PS) to improve performance, our findings proved that pre-magnetized Fe 0 (Pre-Fe 0 ) could significantly enhanced the degradation and dechlorination of 2,4-dichlorophenol (2,4-DCP), and this Pre-Fe 0 /PS process was more efficient than Fe(II)/PS. The Fe 0 before and after magnetization was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), suggesting the acceleration of Fe 2+ release after magnetization. The effects of some important operating parameters such as Fe 0 dosage, PS dosage, pH, and initial 2,4-DCP concentration on the 2,4-DCP degradation and dechlorination by Pre-Fe 0 /PS were investigated and compared with that of Fe 0 /PS, observing a 1.9–5.2-fold enhancement in the degradation rate of 2,4-DCP. Although SO 4 − was the dominant active species responsible for 2,4-DCP degradation in two processes, pre-magnetization could promote more OH generation. Identified by GC–MS and IC, the degradation intermediates such as 4-chlorophenol (4-CP), 2-chlorophenol (2-CP), phenol, and some carboxylic acids were detected, and possible degradation pathway was proposed. This Pre-Fe 0 /PS process was also efficient for 4-chlorophenol and chlorobenzene degradation, obtaining a 5.2 and 3.2 folds enhancement, respectively. This work demonstrated that such a Pre-Fe 0 /PS would be very promising and environmental-friendly for organics degradation and dechlorination since pre-magnetization required no extra energy source while the introduction of Pre-Fe 0 was rather simple and no need to change the present treatment system.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2015
·
IF 3.34
Hongyu Dong,Baoyu Gao,Qinyan Yue,Yan Wang,Qian Li
Impact of pH on coagulation–ultrafiltration (C–UF) process was investigated with respect to coagulation efficiency, floc characteristics and membrane fouling in this study. Ferric chloride (FeCl 3 ) and polyferric chloride with basicity of 1.0 and 2.2 (denoted as PFC 10 and PFC 22 ) were used as coagulants and Fe (III) species in them was measured by a timed complexation spectroscopy method. Floc properties under four pH conditions were evaluated using a laser diffraction particle sizing device. Ultrafiltration experiments were conducted by a dead-end batch unit. The results showed that organic matter removal efficiency was higher under acidic conditions than under other pH conditions and turbidity removal efficiency was higher under alkaline condition. At same pH, FeCl 3 containing higher monomeric and polymeric species (Fe a and Fe b ) had better organic matter removal and higher turbidity removal efficiency was obtained by coagulants with larger percentage of polymer or colloidal species (Fe c ). Flocs formed under acidic ranges were larger, weaker and looser. At pH 4.0, 7.0 and 9.0, flocs by FeCl 3 were larger and weaker than these by PFC 10 , followed by PFC 22 . In case of FeCl 3 and PFC 10 , acidic pH conditions were helpful to reduce membrane fouling. For PFC 22 , permeate fluxes were less sensitive to pH variations.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 9
·7413-7418
·
IF 3.289
Xiaomeng Liu,Lili Ren
Molybdenum phosphide (MoP), synthesized by combining with polyethylene glycol (PEG), shows 4 to 5 times superior activity than conventional MoP for hydrodechlorination of trichloroethylene (TCE). We investigated the effect of PEG average molecular mass on the catalytic activity of MoP, and found that when the average molecular mass of PEG was 8000, the MoP catalyst gave the highest activity. Through X-ray diffraction (XRD), N2 adsorption–desorption, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and H2 temperature-program reduction (H2-TPR), the effect of PEG was investigated. The results showed that the addition of PEG changed MoP from the original flat structure to a lamellar structure, and indeed improved the growth of the (101) and (102) crystal planes (the possible crystal planes of high activity) and restrained the (100) and (201) crystal planes (the possible crystal planes of low activity). This leads to the high catalytic performance of MoP modified with PEG.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
BIOORGANIC CHEMISTRY
·
2017
·
IF 3.231
Ren-Chao Zheng,Jian-Qiang Jin,Zhe-Ming Wu,Xiao-Ling Tang,Li-Qun Jin,Yu-Guo Zheng
2-Chloronicotinic acid (2-CA) is an important building block for a series of agrochemicals and pharmaceuticals. Amidase-catalyzed hydrolysis of 2-chloronicotinamide is one of the most attractive approaches for 2-CA production. However, development of the bioprocess was plagued by low activity of amidase for 2-chloronicotinamide. In this work, an amidase signature (AS) family amidase from Pantoea sp. ( Pa -Ami), with superior activity for nicotinamide and its chlorinated derivatives, was exploited and characterized. Kinetic analysis and molecular docking clearly indicated that chlorine substitution in the pyridine ring of nicotinamide, especially the substitution at 2-position led to a dramatic decrease of Pa -Ami activity. The productivity of the bioprocess was significantly improved using fed-batch mode at low reaction temperature and 2-CA was produced as high as 370 mM with a substrate conversion of 94.2%. These results imply that Pa -Ami is potentially promising biocatalyst for industrial production of 2-CA.
研究领域:
生物化学
·
工业酶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2021
·
IF 11.236
Jia Deng,Enlai Gao,Feng Wu,Zhixiong You,Xiaozhong Li,Shuxian Gao,Li-Zhi Huang
Atomic hydrogen (H•) is highly reactive for the hydrodechlorination of trichloroethylene (TCE). In this work, we found that the coprecipitation of Ni 2+ and Fe 2+ at neutral pH led to an unprecedented catalytic generation of H•. The generated H• effectively dechlorinate TCE to nontoxic ethylene and ethane, and Fe 2+ is the only electron donor. The abundant adsorbed H• produced with a Ni/Fe ratio of 0.4 enhances hydrogen evolution reaction causing a low efficiency for hydrodechlorination. In contrast, the active absorbed H• is generated in the crystal lattice of Ni-Fe hydroxides with a Ni/Fe ratio of 3.0 causing highly efficient hydrodechlorination of TCE. This work not only reveals the mechanism of catalytic hydrodechlorination by Ni-Fe hydroxides at neutral pH, but also provides a novel approach to detoxify TCE in contaminated water using facile precipitated Ni-Fe hydroxides.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Chunhua Zhang,Jiahui Shen,Ji Li,Mei Wan
To study the inhibition characteristics of different chloride salts on the spontaneous combustion of coal and to further reveal why magnesium chloride shows a different inhibitory effect, coal samples from FuSheng Coal Mine No. 15 in Shanxi Province were selected. Based on the characteristics of functional group absorption peak at different temperature, the composition changes and reactivity ranking of the functional groups in oxidized coal samples were tested by thermal oxidation experiments and infrared spectroscopy and analyzed to obtain the chain thermal reactions of different active groups. The weight-loss process and heat release characteristics of raw coal and three chloride salt-containing coal samples (sodium chloride, potassium chloride, and magnesium chloride) were compared and analyzed by synchronous thermal analysis experiments, and their inhibition reaction mechanism were studied. The results showed that different functional groups reacted at different low-temperature stages, and the active groups containing C–H, O–H, C-O, and C = O bonds were important during the spontaneous combustion of coal. In the chain thermal reactions with different active groups, heat and oxidative cleavage of the C-O and O–H bonds determined the chain development of different functional groups, and the R·, RO·, H·, and ·OH, chain thermal reaction products again acted as reactants that promoted further development of the reaction. Sodium chloride and potassium chloride played inhibitory roles in the dehydration-desorption stage and dynamic equilibrium stage through water evaporation and heat absorption, while magnesium chloride participated in the whole coal-oxygen reaction process. The inhibitory mechanism included dehydration and heat absorption by MgCl 2 ·6H 2 O, the complex dehydration of active groups containing O–H, the precipitation and oxygen insulation of [(SH·) n ]Mg and Mg(OH) 2 , the nucleophilic substitution of α-H for RCH 3 and RCH 2 OH groups, and the formation of H…Cl…H bonds.
研究领域:
化学工程
·
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Yanju Chen,Chao Feng,Wenhong Wang,Zhi Liu,Junxi Li,Chenguang Liu,Yuan Pan,Yunqi Liu
Regulating the electronic structure of Pd catalyst for promoting electrocatalytic hydrodechlorination is promising but still challenging. Herein, we propose an electronic structure engineering for accelerating the hydrodechlorination process by desigining bimetallic Pd-Au alloy nanoparticles (ANs) with electron-rich Pd as high-efficiency electrocatalysts. The Pd 7 Au 3 ANs exhibits the highest electrocatalytic hydrodechlorination activity, the 4-chlorophenol hydrodechlorination efficiency reaches 98.35 % within 4 h, and the mass activity is 0.47 h −1 mg Pd −1 , which is 7.83 times as high as that of pure Pd nanoparticles. The experimental characterization and theoretical calculation reveal that Pd atoms “obtain” electrons and gold atoms “lose” electrons in Pd-Au ANs, resulting in the formation of electron-rich Pd, which promotes the desorption of the dechlorination product phenol and accelerates the renewal of active sites. This work provides an electronic structure engineering strategy of Pd-based electrocatalysts for electrocatalytic hydrodechlorination, which opens a new opportunity for rational design and construction of high-performance hydrodechlorination catalysts.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2022
·
IF 9.794
Zanyun Ying,Han Chen,Zheng He,Yutao Hu,Zhipeng Huang,Jialing Gao,Xinya Wang,Jiexu Ye,Jingkai Zhao,Shihan Zhang,Jianmeng Chen
Microbial electrolysis cell (MEC), a promising technology, is being developed for volatile organic compounds (VOCs) abatement. One of the critical issues to limit its industrial application is the poor electron transfer . In this work, anthraquinone-2,6-disulfonate (AQDS) and flavin mononucleotide (FMN) are dosed to MECs for the chlorobenzene (CB) removal, which are denoted as MEC-AQDS and MEC-FMN, respectively. The MEC performance is significantly promoted due to that RMs lower down the internal resistance. The CB removal efficiency in MEC-AQDS and MEC-FMN are increased by 40% and 20%, respectively, compared with neat MEC. Moreover, EC max and K s of MEC-AQDS are 26% and 75% higher than that of neat MEC, respectively. AQDS is a more suitable RM with 66% and 50% higher in dechlorination efficiency and coulombic efficiency, respectively, compared with FMN. The enhancement of dechlorination process in MEC-AQDS is ascribed to two reasons. The lower resistance accelerates the electron transfer rate during dechlorination; and the enhancing growth of dechlorinating bacterium leads to an abundant excretion of dechlorination enzymes. Additionally, electrochemical analysis and intermediate detection imply that RMs affect the electron transfer pathways but not the degradation mechanism , that is, CB converts into 2-chlorophenol and 3-chlorocatechol successively, then ring-opens and dechlorinates for mineralization .
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
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Yinghua Chi,Shiping Xu,Mingxue Li,Maoxia He,Haiyan Yu,Li Li,Qinyan Yue,Baoyu Gao
Photocatalytic degradation of pollutants in high salinity wastewater usually shows extremely low activities and produces highly toxic by-products, often related to the presence of excess chloride ion (Cl − ). Herein, we report for the first time that involvement of Cl − (quenching active species and generating chlorinated by-products) could be effectively blocked during photocatalytic processes. Based on a comprehensive investigation of its mechanism, we found that Cl − could quench superoxide radicals ( O 2 − ) through a cyclic indirect quenching model with holes (h + ) and hydroxyl radicals ( OH) quenching as "initiators". Thus, scavenging h + and OH could successfully block the chain reactions between Cl − and O 2 − , and photocatalytic degradation of methyl orange (a refractory dye, with O 2 − as dominant attacking species) could be enhanced by nearly 50 times, even when Cl − content was up to 10 wt%. More importantly, both HPLC-MS analyses and DFT calculation validated that, by blocking its quenching effect, Cl − could be successfully excluded from the pollutant degradation processes, thus preventing the generation of toxic chlorinated by-products. This work provides new insights into control of chlorinated by-products and proposes feasible strategies to extend photocatalytic technology in high salinity wastewater.
研究领域:
环境科学
·
化学工程
✓ 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）