INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Qiang Chu,Ruoyi Jia,Meng Chen,Yonglu Li,Xin Yu,Yaxuan Wang,Wen Chen,Xiang Ye,Yangyang Liu,Yong Jiang,Xiaodong Zheng
Tetrastigma hemsleyanum Diels et Gilg, a rare herbal plant native to China, possesses high medicinal value. More researches have focused on the flavones in the tubers of Tetrastigma hemsleyanum whereas polysaccharides attract few attentions. In this study, a purified polysaccharide (TTP-1) with the average molecular weights of 478.33 kDa was extracted from Tetrastigma hemsleyanum and conducted multiple analysis to identify its structural information. In vitro , TTP-1 could suppress the inflammation, cytotoxicity, genotoxicity, mitochondrial dysfunction and oxidative damage induced by LPS in RAW264.7 cells. Meanwhile, TTP-1 could attenuate inflammation via COX-2, iNOS, MAPKs pathways and ameliorate oxidative damage through Nrf2-Keap1, Sirt1-FoxO1 pathways in RAW264.7 cells. In vivo , the inflammation induced by LPS triggered the suppression of survival ratio and growing development, as well as the restrain of athletic ability in Caenorhabditis elegans . The treatment of TTP-1 reversed the situation induced by LPS. In a word, TTP-1 could ameliorate LPS-induced inflammation both in vitro and in vivo .
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CHEMOSPHERE
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2019
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IF 5.108
Shizong Wang,Jianlong Wang
Carbon-based materials have been studied as metal-free catalyst for persulfate activation. At present, the activation performance of carbon materials for persulfate is usually characterized by the removal efficiency of organic pollutants. However, the kinetics of persulfate activation by carbon materials has not been investigated. In this study, the kinetics of peroxymonosulfate (PMS) activation by reduced graphene oxide (RGO) and sludge-derived biochar (BC) were investigated. The experimental results showed that the kinetics of PMS activation followed the two-phase kinetic model (fast phase (a 1 ) and slow phase (a 2 )). In the absence of organic pollutants, the a 1 and a 2 were calculated to be 0.320 and 0.0471 min −1 for BC, respectively, and 0.322 and 0.0850 min −1 for RGO, respectively. Based on the characterization of BC and RGO, it can be concluded that the fast phase was mainly due to the formation of surface-bound active species. Competitive adsorption between PMS and targeted pollutants decreased the kinetic constant for the first phase (a 1 ) and the kinetic constant for the second phase (a 2 ) for both BC and RGO. The value of a 1 and a 2 increased for BC after the addition of phenol, due to the enhanced PMS activation by surface adsorbed phenol. The increase of phenol concentration decreased slightly the value of a 1 and a 2 . The increase of PMS concentration increased significantly the value of a 1 and a 2 . The decrease of a 1 and a 2 in repeated use of carbon materials could be due to the decrease of oxygen-containing functional groups and defect intensity.
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RSC Advances
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2019
·Vol. 9
·期 48
·28112-28118
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IF 3.049
Tao Liu,Xiaoxue Yuan,Gang Zhang,Yi Zeng,Tong Chen,Gongying Wang
In this paper, the Fries rearrangement of diphenyl carbonate (DPC) catalyzed by organotin compounds with different coordination groups was studied for the first time. The electronic effect and steric hindrance of the coordinating groups were discussed with respect to the reactivity of DPC rearrangement. The results showed that both the electronic effect and steric hindrance of the coordinating groups influenced the acidity of the active tin centers and then affected the catalytic performance of organotin as a Lewis acid for the rearrangement of DPC, and the influence of the electronic effect is greater than that of steric hindrance. The catalytic activity is in the order of BuSnO(OH) > Bu2SnO > Bu2Sn(OCOC11H23)2 > BuSnCl3 > Bu3SnOSnBu3 > Bu3SnCl, and Bu2SnO showed the best catalytic activity due to its strong electron absorption effect, small steric hindrance, and good stability. Under the optimum reaction conditions, the conversion of DPC was up to 93%, and the yields of phenyl salicylate (PS) and xanthone (XA) were 62% and 28%, respectively. In addition, a reaction mechanism of DPC rearrangement catalyzed by the organotin compounds was speculated. This research can provide vigorous theoretical data support to control the byproducts produced by DPC rearrangement in the process of DPC synthesis. It also provides a new route for the preparation of PS and XA.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
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2019
·Vol. 166
·期 13
·D638
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IF 3.12
Pengfei Xu,Xiaohong He,Junwei Mao,Yongming Tang
In this paper, Ti/SnO2-Sb/Ce-PbO2 anode is electrodeposited from MSA bath, and the effect of Ce3+ concentration in bath on the phase composition and morphology of lead dioxide electrode is elucidated. It is found that with the addition of 2 mM Ce3+ ion to the bath the Ce-PbO2 anode exhibits highest stability in 0.5 M H2SO4, and cerium exists as Ce (IV) in the PbO2 film. The electrocatalytic activity of lead dioxide anode for phenol removal is slightly enhanced by the inclusion of Ce. The significant improvement in electrocatalytic activity can be achieved by the addition of small amount of Bi3+ ion to the bath containing Ce3+ ion. In this study, electrocatalytic activities of various anodes follow the order: Ce,Bi-PbO2 > Ce-PbO2 > undoped PbO2 > Bi-PbO2.
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Nanoscale
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2019
·Vol. 11
·期 38
·17736-17745
·
IF 6.97
Qian Zhu,Fushan Wang,Fengwei Zhang,Zhengping Dong
The direct oxidation of alcohols to esters through a green and cost-effective strategy is a fascinating chemical synthesis route. In this study, an environmentally friendly N-doped porous carbon encapsulated Co-based nano-catalyst was prepared via a simple carbonization procedure, utilizing renewable chitosan, accessible dicyandiamide and low-cost Co(OAc)2 as co-precursors. The obtained Co@NC-2-T catalysts were successfully used in selective oxidation of aromatic alcohols with methanol to esters under atmospheric reaction conditions. The Co@NC-2-900 catalyst (added with 2 g dicyandiamide and pyrolyzed at 900 °C) shows optimal activity and applicability and can also be reused at least six times in the oxidative esterification of aromatic alcohols with excellent stability. The presence of superoxide anion radicals in the current catalytic system was detected by the EPR method, and a possible mechanism of alcohol oxidation to ester was proposed on this basis. Thus, this study provides a facile, eco-friendly, and highly efficient catalytic system for oxidative esterification of alcohols.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2019
·
IF 7.149
Shunke Ding,Yang Deng,Hongwei Li,Chao Fang,Naiyun Gao,Wenhai Chu
Iodinated disinfection byproducts (I-DBPs) are of particular concern in drinking water due to the more cytotoxic and genotoxic properties than their chlorinated and brominated analogs. Formation of I-DBP primarily results from the oxidation of iodide-containing waters with various oxidants and the chlor(am)ination of iodinated organic compounds in drinking water. This study first reports that ferric chloride (FeCl3) can lead to the formation of iodinated coagulation byproducts (I-CBPs) from iodide-containing resorcinol solution or natural waters. The unwanted I-CBP formation involved the oxidation of iodide by ferric ions to generate various reactive iodine species, which further oxidize organic compounds. Although the oxidation rate of iodide by FeCl3 was several orders of magnitude slower than that by chlorine or chloramine, most of the converted iodide under the ferric/iodide system was transformed into iodine and iodinated organic compounds rather than iodate. Formation of four aliphatic I-CBPs was observed, and four aromatic I-CBPs were identified by gas chromatography mass-spectrometry and theoretical calculation. Coagulation of iodide-containing waters with FeCl3 also produced I-CBPs ranging from 12.5 ± 0.8 to 32.5 ± 0.2 μg/L as I. These findings call for careful consideration of the formation of I-CBPs from coagulation of iodide-containing waters with ferric salts.
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JOURNAL OF HAZARDOUS MATERIALS
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2019
·
IF 7.65
Binbin Shao,Hongyu Dong,Liying Feng,Junlian Qiao,Xiaohong Guan
Although several groups have made efforts to study micropollutants degradation by Fe(VI)/sulfite process, the mechanism is far from clear and warrants further investigation. Herein, the degradation kinetics and mechanism of selected micropollutants by sulfite (SO 3 2− )-activated Fe(VI) oxidation were systematically investigated. The oxidation rates of enrofloxacin (ENR) and phenol in Fe(VI)/sulfite process ranged from 0.151 s −1 to 6.18 s −1 at pH 6.5 and 8.0. Sulfite applied in multiple-addition mode improved the degradation efficiency of micropollutants with electron-rich moieties compared to the single-addition mode. Based on results of the quenching experiments and kinetic simulation, Fe(V) was identified as the predominant active oxidant at [SO 3 2− ]/[Fe(VI)] molar ratio of 0.1 to 0.3. However, both Fe(V) and SO 4 − / OH contributed to micropollutants oxidation at [SO 3 2− ]/[Fe(VI)] molar ratio ≥ 0.4 and their contributions were strongly dependent on the properties of micropollutants. The different degradation products of ENR in Fe(VI)/sulfite process at different sulfite dosages further supported the contribution of different active oxidants at different [SO 3 2− ]/[Fe(VI)] molar ratios. The toxicity of the reaction products of ENR towards Vibrio qinghaiensis sp.-Q67 decreased dramatically after Fe(VI)/sulfite treatment. The results of this work may promote the application of sulfite-activated Fe(VI) oxidation in water treatment.
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CARBOHYDRATE POLYMERS
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2019
·
IF 6.044
Ziyan Chen,Yan Zhao,Mengke Zhang,Xiufang Yang,Pengxiang Yue,Dikang Tang,Xinlin Wei
A new polysaccharide (pFSP) was first isolated from the originally discarded fibrous roots part of Chinese traditional herb, Bletilla striata. pFSP was composed of D-glucose, D-galactose and D-mannose in a molar ratio of 1: 2.03: 3.45 with molecular weight of 9.1 × 10 4 Da. It could effectively scavenge DPPH and superoxide radicals with inhibition rate of 64.47% and 72.27% at 5.0 mg/ml, higher than that of polysaccharide from Bletilla striata tuber. Structural investigations of the periodate oxidation studies and Smith-degradation as well as the FT-IR spectroscopy were performed, and combined with 1D and 2D NMR spectroscopy, the repeating unit of pFSP contained (1→4)-linked-α-D-Glcp, (1→4)-linked-β-D-Manp and (1→3,6)-linked-β-D-Manp units, together with the branches of (1→6)-linked-β-D-Galp and terminated with (1→)-linked-β-D-Manp residue.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Zhong-Shuai Zhu,Xiao-Jie Yu,Jin Qu,Ya-Qiong Jing,Yasmine Abdelkrim,Zhong-Zhen Yu
Low crystalline flowerlike cobalt silicate hydroxide (Co 3 (Si 2 O 5 ) 2 (OH) 2 , CoSiO x ) is synthesized by a one-pot hydrothermal approach. Abundant highly active Co OH + is preformed on the surface of CoSiO x , while the low crystallinity of CoSiO x leads to the formation of active 1 O 2 caused by the generation of oxygen vacancy in the valence change cycle between Co 2+ and Co 3+ . The optimal CoSiO x with a high specific surface area of 665.2 m 2 g −1 could expose surface Co OH + , thus rapidly activate peroxymonosulfate (PMS) and accelerate catalytic efficiencies. As a result, at least 11 kinds of organic pollutants could be degraded with 33–242% higher efficiencies than reported. In addition to the common SO 4 - and OH, large amounts of active 1 O 2 endow the CoSiO x /PMS system with superb catalytic performances in diverse conditions, suggesting the excellent adaptability for practical usage. This work provides a new protocol to advance the PMS activation process for high-performance cobalt based heterogeneous catalysts.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Junqin Liu,Pingxiao Wu,ShanShan Yang,Saeed Rehman,Zubair Ahmed,Nengwu Zhu,Zhi Dang,Zehua Liu
This work presents a novel strategy for peroxydisulfate (PDS) activation under controlled non-radical/radical mechanism, which is based on a photo-switch over layered CuFe oxide (CFO). The non-radical mechanism is attained by CFO under dark environment, and the radical mechanism is achieved through the visible light irradiation. Electron paramagnetic resonance (EPR) and density functional theory (DFT) studies demonstrate the non-radical activation mechanism is conducted by the polarization effect of CFO to PDS molecule. The radical mechanism could be elucidated by the one-electron reduction of the PDS by excited electrons on conduction band of CFO. Products analyses based on HPLC-MS and Fukui functions suggest that the non-radical degradation pathway could decrease the generation of halide intermediates, whereas the radical pathway may not be observed with this property. Quantitative structure-activity relationships (QSARs) were established between the observed pseudo-first-order rates of various phenolic pollutants and the classical descriptors (i.e., Hammett constant, Pka, E HOMO and E LUMO ) in the non-radical and radical systems, respectively, to give instructions of pathway choice for different pollutants. Considering the non-radical/radical pathway both have their own unique strengths (e.g., non-radical pathway has high selectivity to pollutants and high utilization efficiency of oxidant, and radical pathway has considerable degradation rate and strong mineralization ability), these pathways should be chosen wisely for pollutant degradation according to reality conditions.
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ENERGY & FUELS
·
2019
·
IF 3.021
Zhiguo Dong,Haiping Yang,Peiao Chen,Zihao Liu,Yingquan Chen,Lei Wang,Xianhua Wang,Hanping Chen
In this study, the chemical structure of corn straw lignin and the catalytic pyrolysis behavior at 350–650 °C in a fixed bed was investigated, with TiO2-based catalysts (load Cu, Fe, and Mo) respective to phenolic compounds production. It was found that β-O-4 is the most frequent linkage in corn straw lignin, up to 89%. The highest selectivity (79%) and yield (21.17 mg/(g lignin)) of phenols was obtained at 450 °C for lignin pyrolysis. TiO2 addition enhanced the production of bio-oil with more phenols formed, and the selectivity of phenols reached 86%, with the yield up to 23.64 mg/(g lignin). With Cu or Fe loading, the yield and selectivity of phenols decreased, but the content of aromatic ketones increased obviously. But with Mo addition, the yield and selectivity of phenols increased apparently to 26.72 mg/(g lignin) and 89%, respectively, especially for monophenols and guaiacols. This suggests that the thermal catalytic activity of TiO2 can be further improved by doping a specific metal.
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Journal of Cleaner Production
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2019
·
IF 6.395
Yong Zhu,Hailun Li,Jingrui Ma,Tingting Xu,Xinyu Zhou,Shiqi Jia,Jiaxin Zha,Dengping Xue,Weili Tao,Qingping Xiong,Jun Yuan,Jing Chen
Polysaccharides (PMM) from Meretrix meretrix Linnaeus exhibit a variety of biological activities; however, conventional purification methods are costly, time consuming and introducing toxic agents. This paper aimed to develop a green and efficient method for the deproteinization of PMM by copper ion chelating aerogel (CCA) adsorption. First, CCA was successfully prepared by copper ion chelating composite aerogel (CA). Then, CCA adsorption was applied to remove protein mixed in PMM. The optimal parameter conditions of this deproteinization method were screened, using the deproteinization rate ( D r %), polysaccharide recovery rate ( R r %) and selectivity coefficient ( K c ) as evaluation indicators , by single factor experiment. The optimal conditions were obtained as follows: CCA dose of 1.4%, pH value of 5.0 and adsorption temperature of 30 °C. Under these conditions, equivalent D r % (93.31 ± 1.33%), higher R r % (93.34 ± 1.08%) and K c (14.01 ± 0.46) were achieved compared with the latest reported deproteinization report. Finally, the effect of deproteinization between CCA adsorption and Sevag method, which is the most classical deproteinization method, were compared to verify the practicability of CCA adsorption. As a result, CCA adsorption not only showed much higher R r % as well as K c , but also would not cause any reagent contamination and environment pressure. In conclusion, CCA adsorption would be a green and highly efficient method with great potential in large-scale environmentally sustainable deproteinization of polysaccharides in the future.
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