Journal of the Australian Ceramic Society
·
2022
·Vol. 59
·期 1
·179-185
·
IF 1.741
Liu Yupu,Wang Shu,Yin Jianan,Li Xin
Based on the construction of type II heterojunction, the one-pot hydrothermal method was employed to synthesize Fe 2 O 3 /WS 2 composites with flower-like structures, which performed significant photocatalytic activities compared with the bare components. The systemic characterizations were employed to reveal the type II heterojunction photogenerated electron transfer mechanism and they further illustrated the path for electron–hole transfer and separation under the effect of heterojunction. Afterward, the photocatalytic properties of the catalysts were evaluated by degrading organic methylene blue and toxic Cr (VI) under simulated solar-driven irradiation. Among those, the best high-efficiency Fe 2 O 3 /WS 2 photocatalyst (2WF) displayed significant photocatalytic properties on pollution degradation in detail, with the Cr (VI) photoreduction rate of 0.35 μmol·min −1 ·g −1 cat. and the MB photooxidation rate of 0.27 μmol·min −1 ·g −1 cat. , respectively. The designed photocatalysts have integrated the three aspects of photocatalytic efficiencies, including the visible light response, prolonged photogenerated carrier lifetime, and sufficient surface active sites due to the amount of surface defects, therefore, this work provides more insights into the utilization of green energy for environmental treatment by heterostructured catalysts.
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STARCH-STARKE
·
2024
·Vol. 77
·期 2
·2400050
·
IF 2.6
Xuesheng Qin,Chengzheng Wang,Zhe Zhang,Wei Ma
Hexavalent chromium (Cr(VI)) has attracted much attention because it is a harmful pollutant. In this study, acid hydrolyzed hydrothermal double modified starch (AHS) and hydroperoxide oxidized starch (HOS) are prepared from natural starch and used for the reduction of chromium (VI) in aqueous systems. The effects of hydrothermal acidolysis and oxidative modification of starch on the reduction rate of Cr(VI) are discussed, including the changes of solubility, swelling power, particle size, content of straight-chain starch, and carbonyl/carboxylic group content. The results of response surface methodology (RSM) optimization show that the influence of reaction conditions on the reduction rate of Cr(VI) by NS is as follows: reaction time > initial pH of solution > reaction temperature > starch to Cr(VI) mass ratio; and on the reduction rate of Cr(VI) by AHS and HOS is as follows: initial pH of solution > reaction time > starch to Cr(VI) mass ratio > reaction temperature.
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RSC Advances
·
2018
·Vol. 8
·期 11
·5749-5759
·
IF 2.936
Pingfan Xu,Siyi Huang,Yuancai Lv,Yi Chen,Minghua Liu,Haojun Fan
To solve the problem of contamination of hexavalent chromium (Cr(VI)), visible-light-driven graphene-based ternary metal chalcogenide nanosheets (rGO/SnIn4S8) were synthesized via a one-pot surfactant-assisted hydrothermal method for the photoreduction of Cr(VI). Characterizations demonstrated that SnIn4S8 nanosheets were uniformly distributed on the surface of rGO and the as-synthesized nanosheets exhibited excellent photocatalytic activity under visible light. In addition, the effects of pH, concentration of critic acid, holes and electron scavengers on the reduction of Cr(VI) were systematically investigated. It was found that 50 mg L−1 of Cr(VI) could be completely removed within 30 min at pH 2 when citric acid served as a hole scavenger. Kinetic studies showed that the photocatalytic reduction of Cr(VI) processes obeyed the pseudo first order model. Further study indicated that the Cr(III) species was immediately adsorbed onto the surface of the rGO/SnIn4S8 nanosheets after photocatalytic reduction of Cr(VI). Additionally, recycling results suggested that rGO/SnIn4S8 nanosheets possessed high recycle ability and stability after repeated use (5 times). This effective and promising work might provide a new strategy for the photoreduction of Cr(VI) and complete removal of chromium from effluent through the novel photocatalyst rGO/SnIn4S8.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Minzhang Li,Rajendran Ramachandran,Thangavel Sakthivel,Fei Wang,Zong-Xiang Xu
In this work, we reported the synthesis of siloxene catalysts from calcium silicide at various topotactic reaction conditions and demonstrated their photocatalytic activity for Cr(VI) reduction under visible light irradiations. The topotactic reaction time influenced the surface area, structure, and optical characteristics of the siloxene, which altered the Cr(VI) photocatalytic elimination efficiency. A large specific surface area (47.04 m 2 g −1 ) and a narrow bandgap (2.45 eV) with hydroxyl-terminated layered silicon of the S-12 h catalyst could enable more active sites for photocatalytic reaction, which results in the improved catalytic performance for Cr(VI) removal. The Density Functional Theory calculations proved the siloxene’s direct bandgap feature and narrow bandgap. The initial Cr(VI) concentration, solution pH, temperature, inert gas, and different scavenger's effects on the photocatalytic performance of the S-12 h catalyst were also investigated. The S-12 h photocatalyst exhibited the Cr(VI) reduction efficiency of 98.6% for the electroplating wastewater that demonstrates the potential application in industrial for treatment of heavy metal ions removal.
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Green Processing and Synthesis
·
2022
·Vol. 11
·期 1
·595-603
·
IF 3.97
Fuhua Wei,Ting Zheng,Qinhui Ren,Hongliang Chen,Junhao Peng,Yufu Ma,Zhengjun Liu,Zhao Liang,Ding Chen
Metal–organic frameworks (Sm-MOFs) were prepared using a microwave-assisted ball milling method with a water solution. The structure was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and SEM, and the thermal stability of the Sm-MOFs was tested by Thermogravimetry (TGA). The results showed that the Sm-MOF material exhibited a favorable effect on removing the organic dye Congo red (CR). When the concentration of CR was 80 ppm, adding 50 mg of Sm-MOF material achieved an adsorption capacity of 396.8 mg·g −1 . The experimental data were analyzed theoretically through dynamics, and the experimental results were consistent with the second dynamics model, with correlation coefficients ( R
2 ) all above 0.99. Comprehensive data analysis revealed that the Sm-MOF materials had great potential for future application in wastewater treatment.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Feifei Zhang,Kunjie Li,Jian Chen,Xinran Zhang,Kebing Li,Hua Shang,Lei Ma,Wujie Guo,Xinlong Wu,Jiangfeng Yang,Jinping Li
Natural gas purification by economic and low-energy adsorptive separation processes is important. However, as a difficult global problem, N 2 removal from N 2 /CH 4 mixtures is challenging because of their similar physical properties. In this study, the separation of N 2 /CH 4 by Cr-metal–organic frameworks (MOFs) (MIL-100Cr, MIL-101Cr and TYUT-96Cr) with various open Cr site densities was studied. Gas sorption isotherms showed that TYUT-96Cr exhibited the highest N 2 /CH 4 uptake ratio (13.67 at 0.01 bar and 298 K) of the selected Cr-MOFs, which was consistent with the highest density of Cr (III) sites. This material provided the highest CH 4 productivity (0.716 mmol/cm 3 ) per cycle for N 2 removal from a 5:95 N 2 /CH 4 mixture to produce 99.99% pure CH 4 , as shown by the breakthrough experiments. Pressure-swing adsorption simulations indicated that, by a two-bed six-step method, pristine 95% methane was enriched to 98.9% by TYUT-96Cr. The largest CH 4 productivity, high breakthrough selectivity and thermal stability of TYUT-96Cr among the Cr-MOFs, made it a promising adsorbent in trace N 2 removal for practical industrial application.
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BIORESOURCE TECHNOLOGY
·
2017
·
IF 5.651
Xingtang Liang,Xiaoyu Fan,Runmei Li,Shirong Li,Shukun Shen,Daodao Hu
A novel chitin-based biosorbent (QCP) was synthesized by cross-linking quaternized chitin and branched polyethylenimine with the aid of epichlorohydrin for efficient removal of Cr(VI) from water. Because it possessed both quaternary ammonium groups and amino groups as well as the hierarchical pore structure, QCP presented a maximum adsorption capacity of 387.7 mg/g according to the Langmuir isotherm at 25 °C. The biosorption of QCP achieved the equilibrium within 40 min and followed the pseudo-second-order kinetic model. QCP worked well even in the solution with high pH and high content of competing anions and, it exhibited an excellent reusability. The main Cr(VI) uptake mechanism was confirmed to be electrostatic attractions between Cr(VI) anions and quaternary ammonium groups as well as the protonated amino groups, and followed by partial reduction of Cr(VI) to Cr(III) by amines and hydroxyls. This work may provide a potential for Cr(VI) removal by chitin-based biosorbents.
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Macromolecular Reaction Engineering
·
2020
·Vol. 15
·期 1
·2000041
·
IF 1.33
Yi Zhou,Xuelian He,Boping Liu
Two (SiO 2 /MgR 2 /MgCl 2 )·TiCl x model catalysts are made by refluxing TiCl 4 with 0.35 wt% Cr modified silica gel/alkyl Mg adducts or silica gel/alkyl Mg adducts, which are named as Cr/Ti-based bimetallic Cat-1 and Ti-based monometallic Cat-2, respectively. The kinetics, active center counting, morphology, and polymer characterizations are studied to disclose the effect of low loading Cr active sites on the Cr/Ti-based bimetallic Cat-1 polymerization under mild conditions. The activity of Cat-1 is 120.4% higher than that of Cat-2, with a 114.1% higher [ C *]/[ M ] value. Morphology results show the Cat-1 fragmentation in the first 3 min is highly accelerated, which helps to release buried clustered Ti sites. Differential scanning calorimetry results show that low-temperature heat absorbing shoulder of polyethylene (PE) from Cat-2 demonstrates the signal of low crystallinity polymer made by Cat-2 during the first 60 s, verifying the fluffy polymer in morphology results. GPC results show PE from Cat-1 has a higher M w in the first 3 min while a lower M w in the end. The Cat-1, which release active sites faster, has a high M w in the early time. Lower M w in the 900 s attributes to the effect of relative lower M w polymer made by Cr sites, compared with Cat-2.
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Desalination and Water Treatment
·
2024
·
IF 1
Rui Wu,Huizhong Wu,Yingxi Wang,Ling Li
In this work, hydroxyapatite/graphene oxide hybrid composites (HAP/GO) were prepared from eggshell by solvothermal method, which was mainly used as adsorbents for Cr(VI) removal in wastewater. The effect of graphene oxide (GO) on the structure and removal efficiency of HAP/GO was discussed. The results showed that the Cr(VI) removal of HAP/GO 10% can reach more than 90% within 1 h, and the adsorption conforms to the first-order kinetics. It was found that the addition of GO changed the pore size distribution of HAP/GO and improved Cr(VI) removal. It can be concluded that the swelling of GO in aqueous solution leads to an increase in the interaction between the dissociated carboxyl groups and Cr(VI), thereby improving the adsorption efficiency.
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CORROSION SCIENCE
·
2022
·
IF 7.72
Jianqiao Yang,Shuyuan Bai,Jiyuan Sun,Hao Wu,Shenghan Sun,Shuzhong Wang,Yanhui Li,Wenhao Ma,Xingying Tang,Donghai Xu
In this study, corrosion tests were performed on Cr-coated Alloy 800 H in 500 °C supercritical water, containing 6000 mg∙L −1 oxygen, for 500 h. After exposure, the structure of the sample can be divided into a Cr 2 O 3 layer with a nanocrystal structure, a residual Cr coating with columnar or equiaxed Cr grains, an inter-diffusion layer including Fe-Ni-rich and Cr-O-rich zones, and an alloy substrate. Transmission electron microscopy was employed for the high-resolution analysis of atom diffusion in the sample. The outward diffusion of Fe and Ni was restrained by the coating, and no oxide exfoliation was observed.
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高影响因子
NANO
·
2020
·
IF 1.566
Xiaorui Zhang,Guohua Li,Enyan Hu,Longjun Xu,Siping Gan,Jiaxin Zhai
Copper-palladium (CuPd)/boron nitride nanosheet (BNNS) nanocatalysts were successfully prepared by a microwave-assisted method by using BNNSs as a carrier. These catalysts with a low noble metal content had a high catalytic activity for Cr(VI) reduction at room temperature. The reaction rate reached 0.04044 s − 1 , which was approximately 2.5 times that of Cu 8 Pd 2 /rGO with the same metal loading amount. Compared with the previously reported PdCu/NG nanocatalysts with a high noble metal content, the reaction rate increased more than five times. This is of great significance to the application of supported metal composites in environmental catalysis. The structure and morphology of the catalyst was characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Several types of control experiments showed that the catalytic activity of the catalysts was not only influenced by the synergistic effect of bimetallic CuPd and metal-BNNSs but also related to the catalytic effect of the BNNS carrier itself.
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TALANTA
·
2015
·
IF 3.545
Fang Yang,Cheng-Xiong Yang,Xiu-Ping Yan
Effective separation of tocopherols is challenging and significant due to their structural similarity and important biological role. Here we report the post-synthetic modification of metal–organic framework (MOF) MIL-101(Cr) with pyridine for high-performance liquid chromatographic (HPLC) separation of tocopherols. Baseline separation of four tocopherols was achieved on a pyridine-grafted MIL-101(Cr) packed column within 10 min using hexane/isopropanol (96:4, v/v) as the mobile phase at a flow rate of 0.5 mL min −1 . The pyridine-grafted MIL-101(Cr) packed column gave high column efficiency (85,000 plates m −1 for δ-tocopherol) and good precision (0.2–0.3% for retention time, 1.8–3.4% for peak area, 2.6–2.7% for peak height), and also offered much better performance than unmodified MIL-101(Cr) and commercial amino-bonded silica packed column for HPLC separation of tocopherols. The results not only show the promising application of pyridine-grafted MIL-101(Cr) as a novel stationary phase for HPLC separation of tocopherols, but also reveal a facile post-modification of MOFs to expand the application of MOFs in separation sciences.
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