CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Boyang Wu,Caiping Liu,Chengyu Fu,Pan Wu,Changjun Liu,Wei Jiang
The recovery and separation of vanadium and chromium from vanadium-containing chromate solution are necessary and valuable for the comprehensive utilization and environmental protection of V-Ti-bearing magnetite ore. In this work, a tetragonal ZrO 2 adsorbent was used for harmless treatment and resource reuse of a low-concentration vanadium-containing chromate solution. Results confirmed that water after treatment met the wastewater discharge standard; in addition, Cr(VI) and V(V) were efficiently separated with the V/Cr separation coefficient of 362.05 for the pH of 3.5 and the V/Cr ratio of 1:1 at the concentration of 80 mg/L. This excellent and stable separation performance of ZrO 2 was ascribed to the competitive adsorption of V(V) and Cr(VI) on ZrO 2 , owing to the strong effect of pH on their adsorption and desorption behavior. V(V) and Cr(VI) in vanadium-containing chromate solution can be removed, recovered, separated and enriched through a two-step adsorption/desorption process. The purity of vanadium and chromium can reach more than 99.8%. The adsorption of vanadium and chromium by ZrO 2 has high application value, which is beneficial to the recovery of resources and environmental protection.
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高影响因子
JOURNAL OF ORGANOMETALLIC CHEMISTRY
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2019
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IF 2.066
Yi Zhou,Xuelian He,Ting Fu,Ning Zhao,Boping Liu
A series of novel Cr/Ti bimetallic polyethylene catalysts were successfully synthesized for the first time through introduction of chromium species into the (SiO 2 /MgR 2 /MgCl 2 )·TiCl x Ziegler-Natta catalysts. The bimetallic catalysts , which showed high activity, were simply prepared by refluxing titanium choloride with chromium modified silica gel/alkyl Mg adducts. Moreover, the effects of chromium content and calcination temperature were investigated in detail. The results obtained in the study were used to systematically discuss a clear relationship between the catalyst preparation condition and the relative performance of different metal active centers. Factors including surface hydroxyl content, catalyst performance in homo-polymerization, ethylene/1-hexene copolymerization were systematic investigated. Comparably, the chromium modified catalyst shows catalytic performance with 89% higher activity, 41.5% higher hydrogen response and 46.3% higher 1-hexene incorporation than the original (SiO 2 /MgR 2 /MgCl 2 )·TiCl x Ziegler-Natta catalyst. A new schematic model was proposed to explain the accelerated activation process of the bimetallic catalysts with kinetic and SEM results: chromium active sites on the outer surface of support react 10 times quicker than Ti active sites initially and help to crack the catalyst particle in the first stage; then the released inner surface active sites start to accelerate the polymerization reaction in the second stage.
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2019
·Vol. 95
·期 3
·665-674
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IF 2.659
Yating Liu,Ming Li,Qingyan Zhang,Picai Qin,Xiandong Wang,Guannan He,Ling Li
BACKGROUND The photocatalytic activity of a pristine semiconductor is unsatisfactory due to the rapid recombination of photogenerated electrons and holes. Constructing composite photocatalysts has proven to be an effective method to suppress electron–hole recombination. The composites composed of two materials usually are synthesized through a two-step process. However, in this work, a simple one-step solvothermal method employing an homogeneous reaction system was adopted to synthesize a tungsten trioxide (WO 3 )-copper sulfide (CuS) nanosheet heterojunction with enhanced photocatalytic properties. RESULTS The formation of the WO 3 -CuS heterojunction was confirmed by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray and X-ray photoelectron spectroscopy analysis. The composites showed improved visible light harvesting ability, and enhanced photoelectric and photocatalytic properties compared with pure WO 3 . The optimized composite displayed a photocurrent almost five-fold greater than the sum of the photocurrents of WO 3 and CuS, and had superior performance for methylene blue (MB) degradation and hexavalent chromium [Cr(VI)] reduction. The MB degradation and Cr(VI) reduction efficiencies were both improved when they co-existed in the photocatalytic system. Interferential ions Cl − and NO 3 − were much less effective in the degradation of MB than in the reduction of Cr(VI). CONCLUSIONS Improved photocatalytic activity was achieved after coupling CuS with WO 3 , due to the enhanced visible light absorption and efficient electron–hole separation. Photogenerated holes were found to be the dominant reactive species in the MB photodegradation process. A synergistic effect existed between MB degradation and Cr(VI) reduction. Interferential ions Cl − and NO 3 − had much greater effect on Cr(VI) reduction than MB degradation. © 2019 Society of Chemical Industry
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高影响因子
APPLIED SURFACE SCIENCE
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2019
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IF 5.155
Xue Bai,Jia Jia,Yanyan Du,Xiaoyun Hu,Jianli Li,Enzhou Liu,Jun Fan
This is the first time we report that P-doped anatase titanium oxide (TiO 2 ) nanosheets can be fabricated by red phosphorus (RP) and TiO 2 nanosheets using simply hydrothermal method, accompanying variation in surface species viz. Ti 4+ , O 2− , Ti 3+ , oxygen vacancies ( V o ) and P 5+ . The defect and impurity levels induced by moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers, resulting in remarkably enhanced photocatalytic activity . Moreover, the enhanced optical absorbance and transfer performance of photo-generated carriers were studied using UV–Vis spectroscopy, photoelectric spectrometry and TR-PL. Importantly, the formation of Ti-O-P bands may accelerated transmission of electrons, giving rise to the effective separation of photo-generated carriers. To the best of our knowledge, the Cr (VI) reduction and RhB removal rate obtained by this hybrid show comparatively competitive among other reports so far. It is believed that this work provide a promising approach for building a novel pathway for electron transport and more photocatalytic reaction centers on photocatalysts.
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Analytical Methods
·
2019
·Vol. 11
·期 27
·3467-3473
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IF 2.378
Zhiyang Lv,Cheng Yang,Yuehong Pang,Weiying Xie,Xiaofang Shen
Dispersive solid phase extraction (d-SPE) is a preponderant methodology featuring direct contact and interaction between adsorbents and analytes. Herein, we used the porous metal–organic framework (MOF) MIL-101(Cr) as a d-SPE adsorbent for pretreatment of edible oil samples and determination of benzo[a]pyrene (BaP). The samples after treatment are applied to determination by high performance liquid chromatography coupled with a fluorescence detector (HPLC-FLD). We optimized the type and dosage of the MOF, diluent and eluent. Under the optimized conditions, this method gave a linear calibration curve for the determination of BaP in the range of 1–30 ng mL−1 (R2 = 0.9958) and the relative standard deviation (RSD) ranged from 1.07 to 8.14% (n = 6). The limit of detection was 0.19 ng mL−1 (S/N = 3) and the recoveries from different types of spiked oil samples were between 88.8 and 118.8%. Compared with conventional methods, the MOF-based d-SPE reduces organic solvent consumption and simplifies operation, which provides potential for application in extraction of hydrophobic targets from oil complexes.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2018
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IF 2.829
Mingjuan Han,Ying Li,Zheng Gu,Huali Shi,Chong Chen,Qiang Wang,Hui Wan,Guofeng Guan
A novel functionalized MOF heterogeneous catalyst (MIL-101(Cr) @MBIAILs), 2-Mercaptobenzimidazole ILs with electron-rich SH groups immobilized onto the surface of the well-defined MIL-101(Cr) frameworks, was constructed and fabricated by the S Cr coordination bond on the basis of the facile post-synthetic modification strategy. The heterogeneous catalyst was measured by XRD , FTIR, SEM, TEM , TGA , EA and N 2 adsorption–desorption, and the catalytic behavior of the catalyst was assessed by the esterification about oleic acid and methanol as a model reaction. The results showed that MBIAILs have been successfully immobilized onto the surface of MIL-101(Cr) frameworks by S Cr coordinate bonds. More importantly, the conversion of oleic acid just decreased from 91.0% to 82.1% when the catalyst had been reused six times. This exhibited the prepared catalyst had superior catalytic behavior and excellent reusability.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Fang Deng,Xiaoying Lu,Yingbo Luo,Jie Wang,Wenjie Che,Ruijie Yang,Xubiao Luo,Shenglian Luo,Dionysios D. Dionysiou
A series of visible-light-driven direct Z-scheme CdS/CuInS 2 nanoplates were fabricated by a facile one-step hydrothermal method, and the molar ratio of CdS to CuInS 2 was optimized. The highest visible-light photocatalytic degradation activity of Z-scheme (1:0.03) CdS/CuInS 2 heterojunction is about 4 times than that of pure CuInS 2 , which is due to the narrowest band gap, the largest BET surface area, the most efficient charge separation and transfer, and the synergistic effect between CdS and CuInS 2 . Meanwhile, Z-scheme (1:0.03) CdS/CuInS 2 heterojunction also exhibits excellent photocatalytic reduction activity with almost 100% of aqueous Cr(VI) reduction efficiency in absence of hole scavengers after 60 min. The special significance is that Z-scheme (1:0.03)CdS/CuInS 2 heterojunction shows excellent stability in five degradation cycles, and can effectively treat real pharmaceutical wastewater with 76.5% COD removal efficiency with aid of H 2 O 2 in 13 h, indicating that Z-scheme CdS/CuInS 2 has a promising prospect in real pharmaceutical wastewater treatment.
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APPLIED SURFACE SCIENCE
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2019
·
IF 5.155
Junzhe Jiang,Yushuai Jia,Yabin Wang,Ruifeng Chong,Liping Xu,Xin Liu
Antibiotic has become an important organic contaminant in surface water, which poses a huge threat to human health and ecosystem. SrTiO 3 is an attractive perovskite structured semiconductor material and shows promising applications in photocatalysis . Herein, a series of lanthanum and chromium codoped SrTiO 3 (denoted as SrTiO 3 (La,Cr)- x ) with different dopant amount of La and Cr have been successfully fabricated via a facile sol-gel hydrothermal method and employed as efficient photocatalysts for the elimination of tetracycline (TC) from aqueous solution under visible-light irradiation. It indicates that the photocatalytic performance is highly dependent on the La and Cr content in the samples. Among the catalysts, the porous SrTiO 3 (La,Cr)-6 spheres with a moderate dopant amount exhibit the best photocatalytic activity for TC removal, which is approximately 4.4 and 2.3 times as superior as SrTiO 3 (La,Cr)-2 with the least dopants and SrTiO 3 (La,Cr)-8 with the most dopants, respectively. Detailed characterizations reveal that the significant improvement of photocatalytic activity is attributed to the increasing molar ratio of Cr 3+ /Cr 6+ , which can be facilely adjusted by tuning the doping amount of La and Cr during the synthesis process. In addition, the catalyst shows excellent photocatalytic stability and can be recycled over ten times with negligible activity decline. Active species trapping experiments demonstrate that superoxide radicals, holes and hydroxyl radicals are responsible for TC degradation. On the basis of the intermediate products identified using HPLC-MS, four possible reaction pathways and TC degradation mechanism have been put forward. This study offers an effective strategy to modulate the photocatalytic properties of SrTiO 3 by simple tuning the dopant content for environment and energy applications, which can be facilely extended to the modification of other semiconductors.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2015
·Vol. 23
·期 2
·1460-1470
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IF 2.828
Chen Wei-fang,Zhang Jinghui,Zhang Xiaomao,Wang Weiya,Li Yuxiang
Nano-zero-valent iron/activated carbon (nZVI/AC) composite was evaluated for its effectiveness in the stabilization of Cu, Pb, Cd, and Cr in dredged river sediment. Synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) were adopted to compare the effects of nZVI/AC dosage, particle size, time duration, and temperature on heavy metal leachability. The results show that leachability dropped considerably with the addition of nZVI/AC and powdered particles in the size of 0.075–0.18 mm was more effective in stabilization than granular ones. Stabilization effect was stable in long-term and robust against changes in temperature. Tessier sequential extraction revealed that heavy metals were associated with solid particle, inorganic or organic matters in sediment. The addition of nZVI/AC was able to convert relatively weakly bound heavy metals into more strongly bound species and thus reduce the bioavailability and toxicity. Also, the standard potential of heavy metals may decide the mechanism of stabilization process.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Hongxu Guo,Dongfang Wang,Jianhua Chen,Wen Weng,Minqiang Huang,Zishan Zheng
A novel metal-organic framework (MOF) material, flake-like NH 2 -MIL-53(Cr), was prepared by a simple reflux method and then characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The as-prepared MOF was found to be an effective material for the selective electrochemical detection of microgram levels of Pb 2+ in aqueous solution. Detection was performed by square wave anodic stripping voltammetry. The NH 2 -MIL-53(Cr)-modified electrode showed excellent selectivity and stability for Pb 2+ detection. The electrochemical properties and applications of the modified electrode were studied. Operational parameters such as pH, deposition potential, and deposition time, were also optimized to detect trace amounts of metal ions. This method offers a new strategy for heavy metal detection using MOF materials.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2017
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IF 4.233
Wenhui Lu,Jinhua Li,Yanqing Sheng,Xinshen Zhang,Jinmao You,Lingxin Chen
Magnetic nanoparticle-multiwalled carbon nanotubes composites (MNP/MWCNTs) were prepared using 1,6-hexanediamine functionalized Fe 3 O 4 nanoparticles (MNP) linked to carboxylic MWCNTs by facile one-pot solvothermal synthesis for highly efficient removal of Cr(VI) from aqueous solution. The easily obtained magnetic nanocomposites were systematically characterized, and several major factors affecting the adsorption-based removal were investigated, including solution pH, adsorbent dosage, temperature and contact time. The removal efficiency was highly dependent on solution pH; low pH facilitated removal with the maximum efficiency at pH 2.0. The adsorption isotherm was well fitted with the Langmuir isotherm model and the adsorption capacity increased with the temperature increasing. The adsorption kinetic data could be well described by the pseudo-second-order and the intraparticle diffusion models, indicating that the intraparticle diffusion was not the only rate-limiting step. The MNP/MWCNTs displayed excellent selectivity and high anti-interference ability toward Cr(VI) when confronted with commonly coexisting ions. By using an external magnetic field, the exhausted MNP/MWCNTs could be readily separated from the solution after adsorption of Cr(VI) and well regenerated, and could keep about 80% removal efficiency in the fifth adsorption-desorption cycle. The simple, rapid and reliable MNP/MWCNT-based method proved to be a cost-effective, convenient and potentially applicable way to targeted pollutant removal and wastewater treatment .
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Yongzhu Yan,Qingda An,Zuoyi Xiao,Wei Zheng,Shangru Zhai
A chemically modified alginate beads for heavy metal removal was prepared using polyethylenimine (PEI) as a modification reagent, which high density active sites were introduced favorably onto the surface by cross-linking reaction, leading to the designing of flexible core-shell/bead-like alginate@PEI sorbent and employed for the adsorption of Cr(VI) from aqueous solutions. This new sorbent was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) etc. The results demonstrated that the optimized pH value was observed at 2.0. The adsorption processes fitted well with the pseudo-second-order kinetic model and the Freundlich isotherm in a batch system. The experimental maximum adsorption capacity for Cr(VI) was 431.6 mg/g under an optimal testing condition, which was much higher than that of sodium alginate (SA) (24.2 mg/g). Thomas and Bohart–Adams models were successfully fitted with breakthrough curves obtained under different experimental conditions in a continuous column process. More importantly, the adsorption capacity of the alginate@PEI only showed a slight loss after ten cycles of adsorption-desorption studies. Compared to other reported adsorptive materials, this core-shell/bead-like composite promises advantages of ultra-high adsorption capacity, low-cost, environmental friendliness and excellent recycling performance.
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