Catalysts
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2020
·Vol. 10
·期 4
·453
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IF 3.52
Emmanuelia Akimana,Jichao Wang,Natalya V. Likhanova,Somboon Chaemchuen,Francis Verpoort
Mild reaction conditions (nearly room temperature and atmospheric CO2pressure) for the cycloaddition of CO2with epoxides to produce cyclic carbonates were investigated applying MIL-101(Cr) as a catalyst. The MIL-101 catalyst contains strong acid sites, which promote the ring-opening of the epoxide substrate. Moreover, the high surface area, enabling the adsorption of more CO2(substrate), combined with a large pore size of the catalyst is essential for the catalytic performance. Additionally, epoxide substrates bearing electron-withdrawing substituents or having a low boiling point demonstrated an excellent conversion towards the cyclic carbonates. MIL-101(Cr) for the cycloaddition of carbon dioxide with epoxides is demonstrated to be a robust and stable catalyst able to be re-used at least five times without loss in activity.Keywords:MIL-101;heterogeneous catalyst;CO2cycloaddition;carbonate;ambient conditions
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LANGMUIR
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2019
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IF 3.683
Yan Xiong,Jie Chen,Ming Duan,Xiang Li,Jun Li,Can Zhang,Shenwen Fang,Rui Liu,Run Zhang
The investigation of adsorption performance at the adsorbent surface can help to reveal the treatment mechanism and improve the treatment efficiency of adsorption technology for heavy metal ions (HMIs). This work developed a methodology to investigate the adsorption behavior of HMI Cr(VI) at the silica surface by confined near-field evanescent wave (CNFEW) measurement. A silica optical fiber (SOF) was used as the adsorption substrate and light waveguide element to integrate both Cr(VI) adsorption and CNFEW production on its surface. According to the sensitive CNFEW response, the adsorption behavior of Cr(VI) was in situ monitored and real-time evaluated. The thermodynamic information of adsorption equilibrium constant (Kads) and adsorption free energy (ΔG) and dynamic information of the apparent adsorption rate (vads) and adsorption time (tads) were obtained through Langmuir isotherm and kinetic fitting, respectively. Different reaction performances between Cr(VI) and adsorption sites were successfully differentiated, evaluated, and characterized. A site-decided-mechanism was therefore presented to describe the surface interaction process for Cr(VI), which including fast adsorption on type I Si–O– site through electrostatic attraction with and slow adsorption on type II Si–OH site through coordinative interaction with ΔGSiOH–Cr(VI)II = −26.18 kJ mol–1. The adsorption mechanism of Cr(VI) at the SOF silica surface was furthermore verified by zeta potential analysis, Fourier transform infrared investigation, and fluorescence imaging. Unlike conventional ex situ or in bulk detection, the present CNFEW-based approach targets the “localized” adsorption of Cr(VI) adsorbed to the solid adsorbent surface. Consequently, our work favorably constructs a surface platform and provides new insights on understanding the adsorption mechanism for HMIs.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Jian Xia,Xiaojuan Lei,Yuqin Lu,Shilin Liu,Xiaogang Luo
In this work, the coagulation mechanism of the cellulose/metal nanohybrids and the binding mode with Cr (VI) are deeply described. Nanohybrids with 3D porous networks were prepared from cellulose/Fe 2 O 3 -SO 3 H solutions through a simple one-step coagulation process in NaCl aqueous solutions. The structure and properties of nanohybrids were characterized by SEM, EDS, XRD, FTIR, and XPS. The cellulose/metal nanohybrids have a langmuir maximum adsorption capacity of 11.46 mg/g. The dissolved metal nanoparticles could form strong hydrogen bonding with cellulose by breaking the intermolecular hydrogen bonds between the polymer molecules. The porous networks of cellulose/metal nanohybrids provided multiple adsorption sites for Cr 2 O 7 2− anion through Fe O … Cr interactions. The cooperation between cellulose and Fe 2 O 3 -SO 3 H nanoparticles makes the hybrids exhibiting a satisfactory selectivity and affinity for Cr (VI). The cellulose/metal nanohybrids selectively interacted with Cr 2 O 7 2− via Fe atom from Fe 2 O 3 and oxygen atom from SO 3 − groups. The Cr (VI) adsorption occurred via a two-step process, the first of them was the initial adsorption of Cr 2 O 7 2− on cellulose/metal nanohybrids surface, followed by the rearrangement of Cr 2 O 7 2− molecules and the consecutive growth of Cr 2 O 7 2− aggregate layers.
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ADVANCED POWDER TECHNOLOGY
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2019
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IF 3.25
Osman Ahmed Zelekew,Dong-Hau Kuo,Hairus Abdullah
Herein, we report the bimetallic (Sn,Zn)(O,S) oxysulfide nanocatalyst with a facile method. The Sn-based catalyst with the addition of Zn was synthesized with the proportions of 0, 20, 30 and 50% of Zn to Sn precursors for preparation. The catalysts were characterized by XRD , TEM , SEM XPS , and UV–vis instruments. The nanocatalysts were also tested for the detoxification of Cr +6 . The Sn-20 catalyst with 20 M percent of Zn(Ac) 2 ·2H 2 O showed an excellent performance for the induced photocatalytic reduction of Cr +6 under visible light irradiation at room temperature. The complete reduction of Cr +6 was achieved within 80 min by Sn-20 catalyst. However, 85.6, 97, and 94% of Cr +6 reductions were achieved within 80 min under visible light illumination by Sn-0, Sn-30, and Sn-50 catalysts, respectively. Hence, the bimetallic (Sn,Zn)(O,S) oxysulfide nanocatalyst will be a candidate and highly potential material for the detoxification of Cr(VI)-containing polluted water.
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JOURNAL OF SOLID STATE CHEMISTRY
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2022
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IF 3.656
Meng Chen,Chao Wang,Lei Wang,Jixiang Xu
In this work, carbon quantum dots@In 2 S 3 hollow tube (CQDs@In 2 S 3 ) with sheet-like hierarchical structure was synthesized by sulfidation CQDs@In-MIL-68. The CQDs@In 2 S 3 -2 exhibited the optimal Cr(VI) reductive ratio of nearly 100% after 45 min light irradiation in solution with pH of 4. The enhanced Cr(VI) reduction activity was ascribed to the efficient separation of electrons and holes after coupling of CQDs. The ·O 2 − was the dominant active specie to reduce Cr(VI), and possible mechanism was proposed. This work provides thought for design of high-performance photocatalysts by loading electron-collecting species to remove environmental pollutants .
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Journal of Materials Chemistry C
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2023
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IF 6.4
Tianqi Zhao,Renagul Abdurahman,Qianting Yang,Ruxiangul Aiwaili,Xue-Bo Yin
Herein, we designed and prepared the persistent luminescence nanoparticles (PLNPs) of γ-Ga2O3:Cr,Ba rationally with Cr ions to achieve the near-infrared (NIR) emission at 700 nm and Ba ions to improve the emission intensity by inducing trap distribution. Energy transfer between γ-Ga2O3 and Cr ions occurs as the emission at 508 nm decreases and that at 700 nm increases along with the increased content of Cr ions. In combination with the trap depth, band gap of the host, and energy levels of Cr ions, an emission mechanism was proposed. Thus, NIR emission (700 nm), high brightness, large Stokes shift (446 nm), and long afterglow time (90 min) were achieved with the optimal γ-Ga2O3:0.0025Cr,0.0012Ba (γGCB) under excitation at 254 nm. The emission intensity of γGCB is temperature-dependent for non-contact ratiometric temperature sensing, and temperature linearity ranging from 300 to 420 K was achieved with an absolute sensitivity of 3.4% K−1. γGCB and γ-G2O3 are white under sunlight but exhibit red and green emissions under single excitation at 254 nm. Thus, Morse and binary codes are adapted to achieve encryption information transfer with the combination of γGCB and γ-G2O3. This work provides ideas for selecting a host, emission center, and trap for PLNPs with desirable properties and thus achieves extensive applications, as validated with ratiometric temperature sensing and encryption information transfer.
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CERAMICS INTERNATIONAL
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2023
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IF 5.2
Kai Xuan,Taiguang Li,Yongmei Hao
Adequate separation of photogenerated carriers plays an important role in the photocatalytic degradation of pollutants. Here, a noble-free spatially separated photocatalyst rGO-CdS-MnO x (GCM) has been designed for removing environmental pollutants efficiently. rGO and MnO x are employed as the collectors of photoinduced electrons and holes, respectively. Under light irradiation, the electrons and holes motivated by CdS can directionally transfer to the rGO and MnO x , leading to the exposure of both reduction and oxidation surfaces, thereby enhancing the photocatalytic activity. Our results demonstrated that GCM-30 can remove 86.56 % of carbamazepine and 95.83 % of tetracycline hydrochloride within 30 min and 15 min, respectively, and 95.49 % of Cr (VI) within 21 min. Our work demonstrates that this dual functional photocatalyst may provide new strategies for the spatially separated photocatalysts for removing environmental pollutants.
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ELECTROCHIMICA ACTA
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2023
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IF 6.6
Guiying Tian,Jian Gao,Minrui Wang,Xintao Wen,Yutong Liu,Jun Xiang,Lei Zhang,Penggao Cheng,Jianping Zhang,Na Tang
Current explosive demand in raw lithium greatly boosts lithium mining, and electrochemical Li-extraction using spinel LiMn 2 O 4 (LMO) from original brine has gained much attentions. In this study, Cr-doped LMO is prepared via a facile precipitation-calcination to elucidate the structural alterations and suppress Jahn-Teller distortion, and a novel hybrid capacitive deionization (HCDI) system of “Li-poor LiMn 1.8 Cr 0.2 O 4 ||brine (recovery liquid)||activated carbon” is constructed for electrochemical Li-extraction. The results prove that Cr-doping effectively suppresses Mn 3+ disproportionation induced by Jahn–Teller distortion, leading to a stabilized spinel framework for long lifespan. Importantly, the Cr-doping LMO realizes a stable (de)lithiation over 500 cycles with low manganese dissolution rate of 0.027% per cycle. Meanwhile, the Li-extraction capacity can reach 22 mg g −1 in 1.0 M LiCl electrolyte with retention rate of 86.05% after 500 cycles. In the assembled HCDI system, average Li-extraction capacity in brine reaches ∼15 mg g −1 after 15 cycles. Therefore, the HCDI system using Cr-doping LMO could introduce a new perspective for the industrial Li-extraction facing original brine.
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CARBOHYDRATE POLYMERS
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2023
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IF 11.2
Zhouyu Miao,Mengya Mu,Hou-Yong Yu,Yanjuan Dong
This study presents a novel and environmentally friendly method for producing cellulose microspheres (CM) with controllable morphology and size using electrostatic droplets. The traditional droplet method for CM production requires complex equipment and harmful reagents. In contrast, the proposed method offers a simple electrostatic droplet approach to fabricate CM10 at 10 kV, which exhibited a smaller volume, linear microscopic morphology, and a larger specific surface area , with a 36.60 % improvement compared to CM0 (prepared at 0 kV). CM10 also demonstrated excellent underwater structural stability, recovering in just 0.5 s, and exhibited the highest adsorption capacity for Cr(VI) at 190.16 mg/g, a 72.15 % improvement over CM0. This enhanced adsorption capacity can be attributed to the unique structure of CM10 and the introduction of more amino groups. Moreover, CM10 displayed good cyclic adsorption capacity and high dynamic adsorption efficiency, making it highly suitable for practical applications. CM10 exhibited remarkable adsorption capacity, stability, and practical value in treating Cr(VI) wastewater. This work proposes a simple and eco-friendly method for producing CM with excellent structural controllability and stability, providing an effective route for wastewater treatment .
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2023
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IF 2.2
Hui Wang,Dengjie Zhong,Yunlan Xu,Haixing Chang,Hongyu Shen,Chunzi Xu,Jiaxin Mou,Nianbing Zhong,Bin Tang
In this work, in view of the poor adsorption capacity of sludge-based biochar, a sludge-based biochar adsorbent co-modified with hydrochloric acid and polypyrrole (PPy/SBC-HCl) was prepared and used to remove Cr(VI) from aqueous solution. Its characterization of SEM, EDS, BET, XRD, FT-IR, and XPS show that the removal mechanism of Cr(VI) by PPy/SBC-HCl includes electrostatic adsorption, ion exchange, reduction, and complexation. The removal efficiency of Cr(VI) by PPy/SBC-HCl decreases with the increase of pH. The coexisting cations Ca2+ and Mg2+ have a slight negative effect on it, while the oxoacid anions have a great negative effect on it. The adsorption of Cr(VI) by PPy/SBC-HCl is a spontaneous endothermic process, which conforms to the pseudo-second-order adsorption kinetic model and the Freundlich adsorption isotherm model. The maximum adsorption capacity is 97.37 mg g−1 at pH 2.0 and temperature 298 K.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2023
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IF 6.2
Yangjie Fu,Yanjie Mao,Longyang Wang,Mengyi Qiu,Youran Xu,Jianying Qian,Men Tan,Kejie Zhang,Derek Hao,Qi Wang,Guoxiang Yang
Proper design and successful synthesis of photocatalysts with efficient interfacial charge transfer, strong redox capabilities, and strong environmental applications are critical. Herein, a novel Z-scheme heterojunction AgI/Ce-2MI nanocomposite with redox-retaining properties was successfully prepared by a simple precipitation method. Compared with AgI and Ce-2MI, the efficiency of the optimized Z-scheme AgI/Ce-2MI composites in photocatalytic reduction of Cr(VI) in water within 75 min could exceed 90%. The reduction rate of AgI/Ce-2MI to Cr(VI) was 0.0277 min −1 , which was 2.6 times and 6.8 times that of AgI and Ce-2MI, respectively. In addition, the cycle performance of AgI/Ce-2MI under different pH conditions was compared, and it was found that under the condition of pH= 2, its five-time catalytic activity stability showed good performance. Moreover, the enhancement process of reactive oxygen species •O 2 - and •OH were further verified by active radical capture experiment and ESR. Therefore, this study can provide a Z-scheme heterojunction nanocomposite photocatalytic process with environmental purification functions.
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INDUSTRIAL CROPS AND PRODUCTS
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2023
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IF 5.9
Xiaojing Qin,Rongrong Tao,Song Cheng,Baolin Xing,Weibo Meng,Yanhe Nie,Chuanxiang Zhang,Jianglong Yu
ZnO based-double functional biochar (ZnO-BC) derived pine sawdust is prepared by microwave heating using simple one-pot method for levofloxacin (LEV) and Cr(Ⅵ) removal from wastewater. ZnO-BC has well developed pore structure with BET surface area of 915.47 m 2 /g, which also has well ZnO crystalline. These characteristics make ZnO-BC available as the adsorbent and photocatalyst for LEV and Cr(Ⅵ) removal wastewater. LEV and Cr(Ⅵ) adsorption date fit well with the Hill and Pseudo-second order equation with LEV and Cr(Ⅵ) adsorption amount of 193.42 and 21.03 mg/g, respectively. The LEV and Cr(Ⅵ) adsorption behavior are determined by the chemisorption process. The hydrogen bond, π-π interaction, surface complexation, pore filling are responsible for LEV removal. While the hydrogen bonding, complexation and redox are crucial to the removal of Cr(Ⅵ) from wastewater. LEV removal is 85.72–97.19% at 15–25 mg/L at 120 min, and Cr(Ⅵ) removal is 72.62–99.9% at 40–60 mg/L at 75 min under UV irradiation. The possible photocatalytic mechanisms of the LEV and Cr(Ⅵ) are further investigated and analyzed.
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