SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zijin Pang,Degang Li,Xinru Wang,Xin Huang,Yu-Shi He,Weimin Zhang,Lipeng Zhang
The electrocatalytic dichlorination (EHDC) shows a promising potential to degrade chlorinated phenols (CPs). It is also a green technology in reducing the corresponding hazardous impact on the environment. In this study, we constructed a catalytic structure which was Pd on a TiO 2 array with oxygen vacancies on carbon fibre paper substrate (Pd/TiO 2 /CFP) by a relatively mild route. Due to the presence of the oxygen vacancies, the resulting strong metal-support interaction (SMSI) effect has been identified which featured a redistribution of spatial charge in Pd/TiO 2 . The electron flow from the oxygen vacancies in the TiO 2 to Pd facilitated the adsorption of Pd with 4-chlorophenol (4-CP) and endowed the Pd metal with an improved chemical reaction kinetics even at a low Pd loading. Experimentally, we studied the dependence of pH, concentration of 4-CP, and working potential on the reaction conditions of EHDC. The results showed that the conversion of 4-CP reached 100 % within 180 min with an apparent rate constant of 2.9 × 10 -2 min −1 and the dominant product was phenol (P). The multi-cycle test illustrated that the Pd/TiO 2 /CFP electrode showed superior stability. The results also revealed that the comprehensive catalytic behavior was much better than those of the Pd/CFP and the TiO 2 /CFP electrodes. The density function theory (DFT) calculations indicated that 4-CP was more preferably absorbed on Pd/TiO 2 /CFP than Pd/CFP due to the SMSI assistance. This study provides a valuable guide in the preparation of precious metal-based electrodes for EHDC with a reduced loading and cost but without performance compromise.
研究领域:
环境科学
·
材料科学
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DOI
高影响因子
Small
·
2024
·
IF 13
Dongmiao Li,Min Lin,Jiangjie Zhang,Chengwei Qiu,Hui Chen,Zhen Xiao,Jinni Shen,Yuanhui Zheng,Jinlin Long,Wenxin Dai,Xuxu Wang,Xianzhi Fu,Zizhong Zhang
Halogenated methane serves as a universal platform molecule for building high-value chemicals. Utilizing sodium chloride solution for photocatalytic methane chlorination presents an environmentally friendly method for methane conversion. However, competing reactions in gas-solid-liquid systems leads to low efficiency and selectivity in photocatalytic methane chlorination. Here, an in situ method is employed to fabricate a hydrophobic layer of TaO x species on the surface of NaTaO 3 . Through in-situ XPS and XANES spectra analysis, it is determined that TaO x is a coordination unsaturated species. The TaO x species transforms the surface properties from the inherent hydrophilicity of NaTaO 3 to the hydrophobicity of TaO x /NaTaO 3 , which enhances the accessibility of CH 4 for adsorption and activation, and thus promotes the methane chlorination reaction within the gas-liquid-solid three-phase system. The optimized TaO x /NaTaO 3 photocatalyst has a good durability for multiple cycles of methane chlorination reactions, yielding CH 3 Cl at a rate of 233 µmol g −1 h −1 with a selectivity of 83%. In contrast, pure NaTaO 3 exhibits almost no activity toward CH 3 Cl formation, instead catalyzing the over-oxidation of CH 4 into CO 2 . Notably, the activity of the optimized TaO x /NaTaO 3 photocatalyst surpasses that of reported noble metal photocatalysts. This research offers an effective strategy for enhancing the selectivity of photocatalytic methane chlorination using inorganic chlorine ions.
研究领域:
化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 26
·15004-15012
·
IF 3.049
Shihan Zhang,Zanyun Ying,Juping You,Jiexu Ye,Zhuowei Cheng,Dongzhi Chen,Jianmeng Chen
A newly isolated strain was identified as Ochrobactrum sp. by 16S rRNA sequence analysis and named as ZJUTCB-1. The strain was able to degrade mono-chlorobenzene (CB) as the sole carbon and energy source under aerobic conditions. This study is the first to report the degradation of CB by the genus Ochrobactrum. The degradation rate of CB reached 170.9 μmol L−1 h−1, which is at least 6 times higher than the previously reported data. The strain can efficiently degrade CB under a rang of temperatures (30–40 °C) and pH (6.0–7.0) with optimum at 40 °C and pH 7.0. Salt concentration higher than 0.05 mol L−1 remarkably reduced the biodegradation capability. Moreover, true oxic condition was not an essential element for biodegradation given that the CB degradation rate of 210.4 μmol L−1 h−1 was obtained under microaerobic condition. Based on the Haldane kinetic model, the maximum specific growth rate was 0.895 h−1, which is the highest in ever described CB-degrading strains. According to GC-MS analysis and enzymatic assay, CB was degraded via the meta-cleavage pathway by using 2,3-dioxygenase and 2-chlorophenol as the main intermediates, producing CO2 and Cl− as the final products. The great performance of CB degradation by Ochrobactrum sp. ZJUTCB-1 provided an alternative for development of more effective and reliable biotreatment process.
研究领域:
环境微生物学
·
生物化学
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DOI
PubMed
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2011
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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
·
电化学
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产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2017
·
IF 6.198
Shenyu Lan,Jinxi Feng,Ya Xiong,Shuanghong Tian,Shengwei Liu,Lingjun Kong
Piezo-catalysis was first used to degrade a nondye pollutant, 4-chlorophenol (4-CP). In this process, hydrothermally synthesized tetragonal BaTiO3 nano/micrometer-sized particles were used as the piezo-catalyst, and the ultrasonic irradiation with low frequency was selected as the vibration energy to cause the deformation of tetragonal BaTiO3. It was found that the piezoelectric potential from the deformation could not only successfully degrade 4-chlorophenol but also effectively dechlorinate it at the same time, and five kinds of dechlorinated intermediates, hydroquinone, benzoquinone, phenol, cyclohexanone, and cyclohexanol, were determined. This is the first sample of piezo-dechlorination. Although various active species, including h+, e–, •H, •OH, •O2–, 1O2, and H2O2, were generated in the piezoelectric process, it was confirmed by ESR, scavenger studies, and LC-MS that the degradation and dechlorination were mainly attributed to •OH radicals. These •OH radicals were chiefly derived from the electron reduction of O2, partly from the hole oxidation of H2O. These results indicated that the piezo-catalysis was an emerging and effective advanced oxidation technology for degradation and dechlorination of organic pollutants.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL RESEARCH
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2018
·
IF 0.668
Can Jin,Feng Wang,Bin Sun,Xiaohui Zhuang
A novel method for the preparation of N-chloroaldimines from commonly available aromatic aldehydes has been developed. The reaction proceeded effectively by two steps: aldehydes were initially transformed into imines and then chloro-substitution with NaClO2 gave the N-chloroaldimines. This simple protocol allows for the preparation of a variety of aromatic N-chloroaldimines in moderate to excellent yields without the isolation of the imine intermediate. We also found that 3-nitrobenzaldehyde and 4-cyanobenzaldehyde were converted into the related benzonitrile directly under the standard conditions.
研究领域:
有机化学
·
合成化学
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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
·
IF 9.446
Mei Ming,Yanlin Ren,Min Hu,Yun Zhang,Ting Sun,Yuling Ma,Xiaojing Li,Weidong Jiang,Daojiang Gao,Jian Bi,Guangyin Fan
Exploring MXenes as supports for synthesis of highly efficient catalysts are extremely important for hydrodechlorination of chlorophenols because of the acute toxicity and strong potential bioaccumulation of chlorophenols. We reported a facile strategy to synthesize Rh nanoparticles deposited on 2D alk-Ti 3 C 2 X 2 (X = O, F) (alk-Ti 3 C 2 X 2 for short) MXene, which was prepared through the removal of the Al layers of Ti 3 AlC 2 and post-treatment by alkalization. Modifying the Ti 3 C 2 X 2 support by alkalization triggered the substitution of surface fluorine groups with surface oxygen species. The changes in the surface chemistry of alk-Ti 3 C 2 X 2 effectively prevented particle aggregation to form well-dispersed Rh nanoparticles in small sizes with relative high metal dispersion, thereafter improving the hydrogen uptake capacity of the catalyst. Consequently, the Rh/alk-Ti 3 C 2 X 2 catalyst significantly enhanced the catalytic performance for the HDC reaction, which could be assigned to the large number of active components from small Rh nanoparticles. This strategy provides a basis for investigating the use of MXenes as supports to synthesize well-defined metal nanoparticles in 2D layered structures for potential applications.
研究领域:
环境科学
·
催化化学
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产品关联
DOI
高影响因子
WATER RESEARCH
·
2019
·
IF 7.913
Xinran Zhang,Pengfei Ren,Weiguang Li,Yu Lei,Xin Yang,Ernest R. Blatchley
The presence of ammonium (NH 4 + ) in drinking water treatment results in inhibition of disinfection efficiency and formation of nitrogenous disinfection by-products. Our previous study found monochloramine (NH 2 Cl) photolysis under 254 nm UV irradiation can be effective for removal of NH 4 + ; however, the mechanisms of NH 4 + degradation in this process were unknown. The kinetics and fundamental radical chemistry responsible for NH 4 + removal in the UV/NH 2 Cl process were investigated in this study. The results showed that the pseudo first-order rate constant for NH 4 + degradation in the UV/NH 2 Cl process ranged between 3.6 × 10 −4 to 1.8 × 10 −3 s −1 . Solution pH affected radical conversion and a higher NH 4 + degradation efficiency was achieved under acidic conditions. The effects of chloride were limited; however, the presence of either bicarbonate or natural organic matter scavenged radicals and inhibited NH 4 + removal. NH 2 Cl photolysis generated an aminyl radical (NH 2 • ) and a chlorine radical (Cl • ) that further transformed to a chlorine dimer (Cl 2 •- ) and a hydroxyl radical (HO • ). The second-order rate constants for Cl • and Cl 2 •- reacting with NH 4 + were estimated as 2.59 × 10 8 M −1 s −1 and 3.45 × 10 5 M −1 s −1 at pH 3.9, respectively. Cl • , Cl 2 •- , and HO • contributed 95.2%, 3.5%, and 1.3% to NH 4 + removal, respectively, at the condition of 3 mM NH 2 Cl and pH 7.5. Major products included nitrite and nitrate, possibly accompanied by nitrogen-containing gases. This investigation provides insight into the photochemistry of NH 4 + degradation in the UV/NH 2 Cl process and offers an alternative method for drinking water production.
研究领域:
环境科学
·
饮用水处理
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Tianze Liu,Xiaobin Liao,Xinna Lin,Jing Yu,Huan Qi,Zhibin Jiang,Jing Zou,Qingsong Li
This study was to evaluate the feasibility of controlling carcinogenic nitrosodiethylamine (NDEA) formation from greenhouse gas adsorbent 3-diethylaminopropylamine (DEAPA) by pre-O 3 in subsequent chlorination/chloramination processes. The result indicated that the NDEA yields (0.4 %) during chlorination was 1.3 times of that during chloramination (0.3 %); pre-oxidation with 4 mg/L O 3 significantly cut down its formation; the reduction rates were up to 67.5 and 48.5 %, respectively. OH scavenger greatly augmented the final NDEA amount from 1.86 to 5.05 μg/L during ozonation , while its roles on subsequent processes differed with disinfection methods as well as O 3 (g) dosages. Most of co-existed substances inhibited NDEA generation, except NO 2 − , CO 3 2− and SO 4 2− , which slightly promoted during ozonation. Basing on Gaussian calculation, GC/MS and UPLC-Q-TOF-MS analysis, the influencing mechanisms of pre-O 3 on NDEA formation in subsequent disinfection processes were proposed. In addition, the calculated toxicity analysis as well as the whole toxicity was applied to evaluate the possibility of pre-O 3 on risk control.
研究领域:
环境科学
·
水处理工程
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毒理学
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DOI
PubMed
高影响因子
GREEN CHEMISTRY
·
2025
·
IF 9.2
Grace Dai Zhen Lee,Zifei Yan,Jing Song,Jian Deng,Guangsheng Luo
Terminal epoxides are important monomers and modifiers that are widely used in the polymer and coating industries. Apart from direct oxidation of alkenes to produce ethylene oxide or propylene oxide, many terminal epoxides are still synthesized through the chlorohydrin method. Due to the limited mass transfer performance and complex thermodynamics and kinetics in this heterogeneous reaction system, the dehydrochlorination reaction still suffers from low reaction efficiency, large amounts of solid precipitation waste, and highly excessive use of alkali. Herein, the dehydrochlorination process of 3-chloro-2-hydroxypropyl neodecanoate (CHPDA), selected as a typical β-chlorohydrin with extremely poor solubility in water, was intensified using phase transfer catalysts (PTCs). The structure–function relationship of PTCs was elucidated and it was demonstrated that tetrabutylammonium chloride (TBACl) is one of the most effective catalysts for heterogeneous dehydrochlorination. Due to the significant promotion of mass transfer by applying a catalytic amount of TBACl, the reaction time was shortened from several hours to just 3 min, and the usage of the reactant sodium hydroxide can be reduced from multiple equivalents to nearly stoichiometric with β-chlorohydrin, while the selectivities of the side products, neodecanoic acid (NDA) and diester, were only 0.4 and 1 mol%, respectively. Compared to existing works, this study could be very helpful for the development of continuous and green synthesis technology for epoxides.
研究领域:
化学工程
·
催化化学
·
绿色化学
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DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Hongming Jiang,Chengyang Li,Luyou Chen,Shuchang Yan,Yan Lin,Zengli Zhao,Zhen Huang,Shujia Wang,Hongyu Huang,Haibin Li
Chemical looping (CL) conversion is a fuel heat utilization technology with CO2 capture and pollution control capability. During the treatment of Cl-containing organic solid waste, a large amount of HCl is generated, along with highly toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans, thereby resulting in serious equipment corrosion and environmental harm. Red mud (RM) produced by the alumina industry is a potential cheap oxygen carrier (OC) with in situ dechlorination capability. In this paper, three types of RM are selected to study the evolution and varieties of Na- and Ca-containing compounds in the process of OC preparation and dechlorination. The dechlorination mechanisms and performances of the RM OCs under various reaction conditions are discussed. The results verify that the Na- and Na/Ca-rich RM OCs exhibit good dechlorination performances at a high reaction temperature. The RM OC components with dechlorination activity include Na in the form of soluble alkali (e.g., NaOH), Na2Ti3O7, and Na6Al4Si4O17, along with Ca in the form of CaO, Ca2SiO4, and CaTiO3, whereas NaAlSiO4, Na1.15(Al1.15Si0.85O4), and Ca2Al2SiO7 are inert. The dechlorination performances of the RM OCs are inhibited by the presence of water vapor and high temperature. In the dechlorination process using RM OCs, HCl first reacts rapidly with active elements on the surface of the OC with high dechlorination efficiency. With the saturation of surface-active elements, the reaction enters the HCl diffusion control stage, when the appropriate particle size of the OC and the gas residence time are helpful for improving the dechlorination efficiency.
研究领域:
环境科学
·
化学工程
·
废物管理
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产品关联
DOI
高影响因子
BIODEGRADATION
·
2023
·Vol. 34
·期 4
·371-381
·
IF 3.6
Yue Caixu,Jia Nan,Lv Xueru,Wang Shenghui
3, 5, 6-Trichloro-2-pyridinol (TCP) is a metabolite of the insecticide chlorpyrifos and the herbicide triclopyr, and it is higher toxic than the parent compounds. Microbially-mediated mineralization appears to be the primary degradative pathway and the important biological process of detoxification. However, little information is available on TCP complete metabolic pathways and mechanisms. In this study, the degradation of TCP was studied with a novel strain Micrococcus luteus ML isolated from a stable TCP degrading microbiota. Strain ML was capable of degrading 61.6% of TCP (50 mg/L) and 35.4% of chlorpyrifos (50 mg/L) at 24 h and 48 h under the optimal conditions (temperature: 35 °C; pH: 7.0), respectively. It could also degrade 3, 5-dichloro-2-pyridone, 6-chloropyridin-2-ol, 2-hydroxypyridine and phoxim when provided as sole carbon and energy sources. Seven TCP intermediate metabolites were detected in strain ML and two possible degradation pathways of TCP were proposed on the basis of LC–MS analysis. Both the hydrolytic-oxidative dechlorination pathway and the denitrification pathway might be involved in TCP biodegradation by strain ML. To the best of our knowledge, this is the first report on two different pathways responsible for TCP degradation in one strain, and this finding also provides novel information for studying the metabolic mechanism of TCP in pure culture.
研究领域:
环境微生物学
·
生物修复
·
代谢组学
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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）