SEPARATION AND PURIFICATION TECHNOLOGY
·
2018
·
IF 3.927
Huang Huang,Kai-Li Shao,Si-Yu Duan,Chu-Ying Zhong
The catalytic effect of copper corrosion products, including copper ions , cupric oxide, and cuprous oxide, on the formation of haloacetamides and haloacetonitriles during chlorination of natural organic matter (NOM), model nitrogenous precursors, and real water samples was investigated. During chlorination of NOM, the presence of these copper corrosion products facilitated chlorine decay, and enhanced the formation of dichloroacetonitrile (DCAN) and dichloroacetamide (DCAcAm) with enhancement ratios of 45–59% and 64–137% after 10 h contact time, respectively. Six amino acids were selected as nitrogenous NOM surrogates for chlorination, and the results show that the enhancement of DCAN and DCAcAm formation by copper corrosion products was only observed for slow reacting amino acids, including glutamine, glutamic acid, and phenylamine , suggesting that copper corrosion products may enhance DCAN and DCAcAm formation by catalyzing NOM portions that are relatively inefficient precursors. When bromide and copper corrosion products were present, the formation of dihaloacetonitriles (DHANs) and dihaloacetamides (DHAcAms) could be enhanced during chlorination of NOM, but the degrees of bromine substitution for DHANs and DHAcAms decreased. Although copper corrosion products facilitated DHAN and DHAcAm hydrolysis with the facilitation increasing as the halogens shifted from chlorine to bromine, increased DHAN and DHAcAm concentrations was observed during chlorination of real water samples in the presence of copper corrosion products, confirming that the copper corrosion products had a catalytic effect on DHAN and DHAcAm formation that exceeded their catalytic effect on DHAN and DHAcAm hydrolysis. This study provides basic knowledge of disinfectant residuals and the fate of haloacetonitriles and haloacetamides in drinking water distribution systems where copper is used, which will be helpful for the management of safe water distribution.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2021
·
IF 2.545
Ming Zhang,Fengqi Zhao,Hui Li,Yifan Jiang,Yanjing Yang,Xiaoting Hou,Jiankan Zhang,Na Li
Graphene-based ferrocene nanocomposites play a positive role in improving the comprehensive properties of solid propellants containing ammonium perchlorate (AP). Novel graphene-based ferrocene nanocomposites with different molecular structures were successfully fabricated and characterized systemically using SEM, EDS, FTIR, RAMAN and XPS instruments. Additionally, the catalytic performance of the as-synthesized graphene-based ferrocene nanocomposites on the thermal decomposition and kinetics behavior of AP were studied using DSC and kinetic methods. The result showed the excellent catalytic performance of graphene-based ferrocene nanocomposites, and the molecular structure plays a significant influence on thermal decomposition of AP. Among the nanocomposites considered, the as-synthesized graphene-based ferrocene nanocomposite NG-550-Fe (γ-aminopropyl triethoxy silane as modifier) owns best catalytic activity, and the decomposition peak temperature and activation energy of AP + NG-550-Fe was reduced by 137.7 °C and 151.6 kJ·mol −1 respectively, compared with pristine AP. Combined with the reported studies, the relatively stronger combination of KH-550 and the better dispersion of Fe may be the reason why NG-550-Fe is more effective than other graphene-based ferrocene nanocomposites and traditional supported graphene nanocomposites studied. Results of this study have implications concerning the rational design of graphene-based catalyst, and help to better understand their catalytic performance and mechanism on AP decomposition.
研究领域:
材料科学
·
化学动力学
·
固体推进剂研究
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 21
·8952-8959
·
IF 3.288
Hehe Qin,Jinhong Fan,Shun Mao
The Fenton method is an important water treatment process. However, the mechanism of the Fenton reaction is still not widely recognized. In this article, the autocatalysis process responsible for the degradation of 4-chlorophenol (4-CP) as well as the generation of Fe(II) and the decomposition of H2O2 is elaborated using a Fe(III)/H2O2 system. It was found that the one electron reduction of Fe(III) to Fe(II) via oxidization of H2O2 to ˙HO2 is not spontaneous according to the standard electrode potential rather than being limited by the rate constant of 0.0027 M−1 s−1 in view of the Haber–Weiss circulation. However, the reaction of Fe(III) and 4-CP is spontaneous with a second-order kinetic rate constant of >0.12 M−1 s−1 and a conversion rate of 0.56%, which triggers the switch of the Fenton-like reaction as a real rate-determining step. The circulation of Fe(III) to Fe(II) in the proposed Fenton-like reaction mechanism depends on the organic species and various intermediates, which indicates its reaction selectivity, preferable for organics with a stronger thermodynamic and kinetic activity. Besides, a slight pH decline with time-scale and the stoichiometric ratio of ˙OH to H2O2 and H2O2 to 4-CP being 1 and 2, respectively, pointed to the new proposed reaction mechanism. The discovery of the new reaction mechanism might promote the theoretical and technical advancement of the Fenton-like process.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 6
·期 2
·866-871
·
IF 3.84
Yang Lei,Chuh-Shun Chen,Jia Ai,Heng Lin,Yao-Hui Huang,Hui Zhang
How to effectively activate oxidants like hydrogen peroxide (H2O2), peroxydisulfate (PDS) and peroxymonosulfate (PMS) is the focus of advanced oxidation processes (AOPs). In this study, we have found that PMS can directly decolorize cationic dyes without activation in a wide pH range (2.0–12.0). In addition, the presence of Cl− results in the formation of free available chlorine species and thus improves the degradation efficiency as well as broadening the scope of target pollutants. The first-order rate constant increased by 4.3 times when 2.5 mM Cl− was added as observed by an increase from 0.021 to 0.089 min−1, which further rose to 1.371 min−1 when Cl− was present at a level of 50 mM. Furthermore, it was found that only PMS has such an amazing effect while H2O2 and PDS do not. Radical quenching experiments and electron paramagnetic resonance (EPR) studies show that the decolorization of cationic dyes by PMS does not rely on the formation of sulfate radicals. A plausible mechanism is that cationic dyes (i.e., RhB+) first form a complex with the active component of PMS (HSO5−) owing to their electrical interaction. Subsequently, direct electron transfer from cationic dyes to HSO5− may occur and probably this is responsible for the bleaching of cationic dyes.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 10
·1652
·
IF 5.719
Qi Chen,Haichao Li
Carbon nanostructures (carbon nanotubes, nano carbon spheres, layered carbon nanostructures) were prepared from a sodium dodecyl sulfonate @ sodium chloride system. Sodium dodecyl sulfonate was used as a carbon source. A sodium chloride crystal in the carbonization procedure was used to separate ordered aggregates of sodium dodecyl sulfonate. The results show that different carbon nanostructures were prepared at low concentrations (1CMC~5CMC) by controlling the concentration of sodium dodecyl sulfonate, such as nano carbon spheres and carbon nanotubes, and that layered carbon nanostructures were formed at high concentrations (10CMC). The prepared carbon nanostructures were characterized by transmission electron microscopy, fluorescence spectrometry and Raman spectrometry. The results of this experiment show that the surfactant @ salt system is a potential method for the preparation of carbon nanostructures.
研究领域:
材料科学
·
纳米技术
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
C.S.K. Mishra,Suryasikha Samal,Rashmi Rekha Samal,Binayak Prasad Behera,Pragyan Pallavini,Priyadarshini Dash,Satyabrata Brahma,Tanushree Moharana,Stutiprgnya Pradhan,Pratik Acharya
The use of plastics has increased significantly with consequent rise in the generation of wastes. Microplastics (MPs) with particle size <5 mm are produced in natural terrestrial habitats by weathering of the discarded plastic debris and therefore are likely to impact soil biota . Earthworms are the dominant soil fauna which play vital role in soil formation and decomposition of organics. Since these animals are soil feeders, MP particles contaminating soil are likely to enter in to the gut of these animals affecting their physiology. MPs have been shown to be potent adsorbents of various other pollutants such as heavy metals and agrochemicals . This study reports the effects of two MPs, polyvinyl chloride (PVC) and polypropylene (PP) alone and in combination with the pesticide monocrotophos in soil on tissue protein, lipid peroxidation (LPX), activities of lactate dehydrogenase (LDH) and catalase (CAT) of an epigeic earthworm Eudrillus eugeniae over an exposure period of 48h. Results from molecular docking and laboratory experiment confirmed that both the MPs are potent adsorbents of the pesticide and enhanced oxidative stress on the animal with significant reduction in protein, increased LPX level and enzyme activities . PP indicated significantly higher pesticide adsorption relative to PVC.
研究领域:
环境科学
·
生态毒理学
·
土壤生物学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2020
·
IF 4.302
Hui Yu,Yongfeng Zhu,Aiping Hui,Fangfang Yang,Aiqin Wang
The aqueous foam template without any solvent and only using the particles stabilizer has attracted much attention for preparation of the porous adsorbents. Herein, a novel porous adsorbent was fabricated via thermal-initiated polymerization of Pickering aqueous foams, which was stabilized by the natural sepiolite (Sep) and pine pollen, and utilized for the removal of antibiotic from aqueous solution. The stabilizing mechanism of Pickering aqueous foam of that the Sep was modified with the leaching substance from pine pollen and arranged orderly around the bubble to form a dense “shell” structure was revealed. The adsorbents possessed the hierarchical porous structure and excellent adsorption performance for antibiotic of chlorotetracycline hydrochloride (CTC) and tetracycline hydrochloride (TC). The equilibrium adsorption capacities of CTC and TC were achieved with 465.59 and 330.59 mg/g within 60 min at 25°C, respectively. The adsorption process obeyed Langmuir model and pseudo-second-order adsorption kinetic model. This work provided eco-friendly approach for fabricate porous adsorbents for wastewater treatment .
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Ruihan Xiong,Xiaoting Wei,Wei Jiang,Zhuojun Lu,Qian Tang,Yiqun Chen,Zizheng Liu,Jianxiong Kang,Yuanyao Ye,Dongqi Liu
This study describes the photodegradation of chloramphenicol (CAP) in micro-polluted water with a thin-layer inclined plate reactor. Under simulated sunlight irradiation, the effect of reaction parameters including solution pH, initial CAP concentration, and co-existed humic acid (HA) or chloride was evaluated. The photodegradation of CAP was independent of initial pH in the range of 6.0–9.0, but sharply decreased by 25.5% with the increase of initial CAP concentration from 0.4 to 1.0 mg/L. The presence of HA exhibited a significant inhibitory effect, while Cl − promoted the photoreaction. In this study, CAP was degraded through both direct and indirect photolysis, in which 1 O 2 was the main reactive species responsible for the indirect route. Its steady-state concentration in the micro-polluted water was determined to be 1.40 × 10 −13 mol/L. Transformation intermediates were identified to propose the degradation pathway of CAP, which substantially met the density functional theory (DFT) calculation results. Moreover, four other pharmaceuticals including tetracycline , doxycycline, oxytetracycline , and minocycline were also successfully photodegraded during 5 h irradiation. Therefore, the designed circulatory thin-layer inclined plate reactor is suggested to be effectively applied to the decontamination of organic micro-polluted water.
研究领域:
环境科学
·
药学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Bing Jia,Xiaobo Jiang,Xiubin Chen,Shihua Dong
Liquid-liquid equilibrium (LLE) data for water + epichlorohydrin + {chloroform or isopropyl ether or methyl tert-butyl ether or isopropyl acetate or ethylacetate or 2-ethyl-1-hexanol} systems at 308.2 K under 101.3 kPa were determined. The distribution coefficient and the separation factor were used to judge the extraction efficiency of different solvents on epichlorohydrin removal from water. The Othmer-Tobias, Hand, and Bachman equations were applied to check the reliability of the experimental LLE data. Furthermore, the experimental LLE data were successfully correlated with the NRTL and UNIQUAC models with all the RMSD values were less than 0.57%.
研究领域:
化学工程
·
物理化学
✓ 已验证
DOI
高影响因子
Journal of Bioresources and Bioproducts
·
2020
·
IF 0
Guodong Feng,Yan Ma,Meng Zhang,Puyou Jia,Chengguo Liu,Yonghong Zhou
Waste cooking oil was modified to prepare bio-base plasticizers (a, b and c) with terephthalic acid, adipic acid and benzoic acid by transesterification, epoxidation and ring opening reactions, respectively. The polyvinyl chloride (PVC) films (a/PVC, b/PVC and c/PVC) were prepared using a, b and c as bio-base plasticizers. The epoxidation and ring opening reactions were mainly investigated through GC-MS analysis. The structures of bio-base plasticizers (a, b and c) were confirmed by Fourier transform infrared spectroscopy (FT-IR), 1 H NMR and 13 C NMR. The mechanical properties of a/PVC were as good as those of PVC films with the dioctyl phthalate (DOP) plasticizer. Meanwhile, the elongation at break of c/PVC reached 422%. The glass transition temperature ( T g ) from dynamic mechanical analysis (DMA) was reduced to 30.6˚C, 45.3˚C, 23.6˚C and 40.6˚C, respectively when 40 phr of a, b, c and DOP plasticizer were added. Results of thermogravimetric analysis (TGA) illustrated that the thermal degradation stabilitiy of a/PVC films was better than those of c/PVC and DOP/PVC. The volatility losses of a, b and c were lower than that of the DOP. Bio-base plasticizers a and c exhibited excellent migration resistance in different solutions (distilled water, 50% ethanol (w/w)). The FT-IR of PVC films showed that the downfield shifts of the —CH—Cl groups of the PVC plasticized with a and c were greater than that of b/PVC. The bio-base plasticizers b had a better plasticizing effect at low temperature.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
CHEMOSPHERE
·
2020
·
IF 5.778
Wenrui Xiang,Jingyi Chang,Ruijuan Qu,Gadah Albasher,Zunyao Wang,Dongmei Zhou,Cheng Sun
Bromophenols (BPs) are ubiquitous phenolic contaminants and typical halogenated disinfection byproducts (DBPs) that are commonly detected in aquatic environments. The transformation of 2,4-dibromophenol (2,4-DBP) during chlorination process was fully explored in this research. It was found that active chlorine can react with 2,4-DBP effectively in a wide pH range of 5.0–11.0, with an apparent second-order rate constant ( k app ) varying from 0.8 M −1 s −1 to 110.3 M −1 s −1 . The addition of 5 mM ammonium ions almost completely suppressed the reaction via competitive consumption of free chlorine. With the concentration of HA increasing from 1.0 to 10.0 mg L −1 , the inhibition on the degradation of 2,4-DBP increased from 8.7% to 63.4%. By contrast, bromide ions at a concentration of 5 mM accelerated the process by about 4 times, due to the formation of hypobromous acid. On the basis of the eleven products (with eight nominal masses) identified by LC-TOF-MS, electrophilic substitution reactions and single-electron transfer reactions were mainly involved in the chlorination process. The concentration of primary chlorine-substituted products was about 4 times that of the dimer products, demonstrating that electrophilic substitution reaction was predominant during chlorination of 2,4-DBP. Density functional theory (DFT) based calculations revealed that HOCl is the dominant active oxidizing species for elimination of 2,4-DBP and coupling reaction occurs more easily at para and ortho position of hydroxyl group in the phenolic moiety. These findings could provide some new insights into the environmental fate of bromophenols during chlorine disinfection of water and wastewaters.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Shuwen Wu,Aiyun Jiang,Xiaofei Zhou,Yingliang Liu,Shaokui Cao
Mercuric chloride as main catalyst for acetylene hydrochlorination poses a serious hazard to the environment due to its easily volatilizing and highly toxic characteristics. Mercuric-free catalysts, especially metal-free catalysts, are quite intriguing in the industrial production of acetylene hydrochlorination. In this work, nitrogen-doped biochar is prepared as green metal-free catalyst for acetylene hydrochlorination with natural walnut shells as starting material, in which the condensation product of dicyandiamide or dicyandiamide-formaldehyde is applied as nitrogen source. The 2.5DF/BC-850 catalyst exhibits superior catalytic activity with C 2 H 2 conversion of 94.5% at 220°C and 45 h −1 , which is attributed to the high content of quaternary nitrogen as active center. The introduction of formaldehyde effectively inhibits the carbon deposition in the catalytic reaction and improves the thermal stability of metal-free nitrogen-doped biochar catalyst. This work provides a significant insight into the design of environmentally friendly metal-free nitrogen-doped biochar catalysts for acetylene hydrochlorination.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）