CARBOHYDRATE POLYMERS
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2022
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IF 10.723
Zhi Chen,Zhi-Bo Zhang,Jun Zeng,Zhi-Jie Zhang,Shan Ma,Cong-Ming Tang,Jun-Qiang Xu
In this work, a polyethyleneimine-modified chitosan/Ce-UIO-66 composite hydrogel (PEI-CS/Ce-UIO-66) was prepared using the ex-situ blend method. The synthesized composite hydrogel was characterized by SEM, EDS , XRD, FTIR, BET, XPS, and TG techniques, while the zeta potential was recorded for sample analysis. The adsorbent performance was studied by conducting adsorption experiments using methyl orange (MO), which showed that PEI-CS/Ce-UIO-66 exhibited excellent MO adsorption properties (900.5 ± 19.09 mg/g). The adsorption kinetics of PEI-CS/Ce-UIO-66 could be explained by the pseudo-second-order kinetic model , and its isothermal adsorption followed the Langmuir model. Thermodynamics showed that the adsorption was spontaneous and exothermic at low temperatures. MO could interact with PEI-CS/Ce-UIO-66 via electrostatic interaction , π–π stacking, and hydrogen bonding . The results indicated that the PEI-CS/Ce-UIO-66 composite hydrogel could potentially be used for the adsorption of anionic dyes.
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APPLIED SURFACE SCIENCE
·
2022
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IF 7.392
Yaoyu Zhang,Yuxiong Wang,Yue Liu,Huimin Xu,Zhongbiao Wu
Aiming at the coexistence of pollutants in the actual industrial process, the catalytic oxidation of acetonitrile and ethyl acetate mixture on the Cu–Ce/ZSM–5 catalyst was studied. The mutual inhibition effect during catalytic removal of acetonitrile and ethyl acetate mixture was observed. Acetonitrile showed a more obvious inhibitory effect on the conversion of ethyl acetate, and the introduction of ethyl acetate reduced the N 2 selectivity of acetonitrile oxidation. The simulation results demonstrated acetonitrile could be preferentially adsorbed on Cu center of the catalyst surface, leading to significant inhibition of the initial conversion of ethyl acetate. In addition, the coexistence of ethyl acetate would weaken the hydrolysis of acetonitrile to generate carboxylic acid and –NH x species. As such, no enough adsorbed NH x species could be used to reduce the NO x produced by excessive oxidation of acetonitrile, resulting in a decreased in N 2 selectivity. This study could provide reference on the application of catalysts for cyanide–containing waste gas degradation.
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CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Shaoxia Yang,Qing Wang,Huazhang Zhao,Daoqing Liu
The intrinsic properties of metal-based adsorbents originate from multiples factors such as surface functional groups, electronic and dimensional structures. However, the synthetic strategies are limited to top-down methods, which inhibited the improvement of adsorbent performance. Herein, Fe-Ce bimetal oxide composites are prepared by a bottom-up modified MOF template method. MOF template-directed nano rod-like morphology can expose more active sites and facilitate phosphate access to active sites. The introduction of citric acid effectively increased the amount of surface –OH groups and greatly improved the phosphate adsorption capacity. Furthermore, the Fe dopant enables the high Ce(III) fraction and generate magnetic property for Fe-Ce bimetal oxide composites, which are capable of enhancing the intrinsic phosphate adsorption performance. The results show that the optimized Fe-Ce bimetal adsorbent showed remarkably high phosphate adsorption capacity, achieving a maximum phosphate adsorption capacity of 357 mg g −1 by Langmuir model. High adsorption capacity and high magnetic separation efficiency characteristics make this adsorbent a promising material for phosphate treatment. The above results further prove the effectiveness of the bottom-up strategy in the design process of environmental functional materials.
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Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Zhengjun Qu,Xiaoshen Xu,Hongfei Ren,Ting Sun,Lihui Huang,Zhenhui Gao
Clay-based composite materials have been widely used for environmental remediation due to their excellent physicochemical properties , however, there are few studies on clay-based composite materials as ozone catalyst carriers. In this study, Ce-loaded sepiolite (Ce/SEP) catalyst was synthesized using an impregnation-calcination method. Ce/SEP catalysts had a higher efficiency for heterogeneous catalytic ozonation than sepiolite alone. Among different mass ratios of Ce element to sepiolite (5 % Ce/SEP, 7 % Ce/SEP, 10 % Ce/SEP, and 15 % Ce/SEP), 10 % Ce/SEP showed the best catalytic performance with the mineralization efficiency of p-nitrophenol (PNP) as 71 % that was 1.15, 1.08, and 1.18 times higher than that of 5 % Ce/SEP, 7 % Ce/SEP, and 15 % Ce/SEP, and increased by 30 % compared to that of the ozonation alone. Larger surface area and abundance of strong acid sites of Ce/SEP favored adsorption of ozone molecules on the catalyst surface. High content of oxygen vacancies in the catalyst promoted Ce 3+ /Ce 4+ cycling and subsequently a superior catalytic activity of the Ce/SEP catalyst. In addition, free radical quenching experiments as well as electron spin resonance analysis indicated that hydroxyl radical (∙OH) was the main contributor to the mineralization of PNP in this system. This study provides a novel strategy for the heterogeneous catalytic ozonation of refractory organic pollutants in water.
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GREEN CHEMISTRY
·
2022
·Vol. 24
·期 5
·2240-2248
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IF 11.034
Yanlong Qi,Ruilin Feng,Shijun Liu,Long Cui,Quanquan Dai,Chenxi Bai
Functionalized monomers are of utmost importance in producing new polymers and smart materials. Herein, a two-step approach involving heterogeneous catalysis was developed to produce a functionalized monomer (2-vinylfuran) from bio-based furfural, giving an overall yield of 89%. Economic analysis suggests that this facile approach incurs much lower costs, and its practicality improves the availability of 2-vinylfuran. This is due to the delicate structure of the optimized 4Na5Ce/SiO2, where Na species are present at the oxygen vacancies of the ceria that protect the catalyst structure from collapse, and the catalyst consequently displays excellent performance. Density functional theory (DFT) calculations revealed that the reaction occurs on the Na and Ce species. The adsorption of a furan group onto Na led to side reactions, which were suppressed in the presence of Ce, resulting in higher selectivity. Finally, a polymer based on 2-vinylfuran was prepared, which shows good surface properties and thermodynamic stability.
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MATERIALS CHARACTERIZATION
·
2023
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IF 4.7
Jiwei Yao,Hui Yong,Yang Zhao,Chengyan Sun,Xianliu Xu,Baosheng Liu,Dongliang Zhao,Jifan Hu,Yanghuan Zhang
The Mg 90 Ce 5 Y 5 + x wt% ZnF 2 ( x = 3, 6, 10, 15) composites were prepared by mechanical ball-milling. The effects of ZnF 2 contents on the hydrogen absorption and desorption properties of Mg 90 Ce 5 Y 5 alloy were investigated by XRD , ICP-OES, TEM, PCT and DSC . The excellent hydriding-dehydriding characteristics of the samples after activation were attributed to the catalytic effect of the MgF 2 and MgZn 2 phases introduced in situ by the addition of ZnF 2 . The Mg 90 Ce 5 Y 5 + 6 wt% ZnF 2 composites exhibit the fastest hydrogen adsorption/desorption kinetics and lower decomposition temperatures. At 360 °C, 4.12 wt% H 2 can be absorbed within 180 s, and completely dehydrogenated within 740 s. In addition, the activation energy of dehydrogenation is reduced to 89.5 kJ/ mol, the optimal dehydrogenation temperature is reduced to 318 °C. It is due to the generation of in situ catalysts that weaken the Mg H bond energy, refine the grain sizes , expand specific surface area and increase hydrogen diffusion paths. However, the improvement of the thermodynamics of the composites is limited, the enthalpy is 75.9 kJ/mol H 2 .
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Polymers
·
2024
·Vol. 16
·期 12
·1747
·
IF 4.7
Qi Cheng,Xiaoyu Du,Zuyao Fu,Zhaoyang Ding,Jing Xie
Increasing concern over the safety of consumable products, particularly aquatic products, due to freshness issues, has become a pressing issue. Therefore, ensuring the quality and safety of aquatic products is paramount. To address this, a dual-mode colorimetric–fluorescence sensor utilizing Ce-MOF as a mimic peroxidase to detect H2S was developed. Ce-MOF was prepared by a conventional solvothermal synthesis method. Ce-MOF catalyzed the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to produce blue oxidized TMB (oxTMB). When dissolved, hydrogen sulfide (H2S) was present in the solution, and it inhibited the catalytic effect of Ce-MOF and caused the color of the solution to fade from blue to colorless. This change provided an intuitive indication for the detection of H2S. Through steady-state dynamic analysis, the working mechanism of this sensor was elucidated. The sensor exhibited pronounced color changes from blue to colorless, accompanied by a shift in fluorescence from none to light blue. Additionally, UV–vis absorption demonstrated a linear correlation with the H2S concentration, ranging from 200 to 2300 µM, with high sensitivity (limit of detection, LOD = 0.262 μM). Fluorescence intensity also showed a linear correlation, ranging from 16 to 320 µM, with high selectivity and sensitivity (LOD = 0.156 μM). These results underscore the sensor’s effectiveness in detecting H2S. Furthermore, the sensor enhanced the accuracy of H2S detection and fulfilled the requirements for assessing food freshness and safety.
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LANGMUIR
·
2023
·
IF 3.9
Qiang Ma,Lijun Jiang,Bowen Yang,Bowen Xu,Qingyuan Wang,Qihong Wu,Ping Ning,Yingjie Zhang,Jin Huang,Jiming Hao
Gaseous thallium (Tl) pollution events, primarily caused by non-ferrous mineral refineries and fossil fuel combustion, have increased over the past few decades. To prevent gaseous Tl distribution from flue gas, MnO2/CeO2@HKUST-1 (MCH) was synthesized and found to achieve a gaseous Tl(I) removal level of up to 90% at 423 K, a weight hourly space velocity (WHSV) of 2000 h–1/mL with an Mn dose of 10%, maintained over 10 h. The best Mn/Ce ratio was found to be 9:1. To further investigate surface kinetic behavior, four commonly used kinetic models were applied, including the Eley–Rideal (ER) model, Langmuir–Hinshelwood (LH) model, Mars–van Krevelen (MVK) model, and pseudo-first-order (PFO) model. While the ER and LH models had the slightest deviation, the MVK model was the most reliable. The CatMAP software was also used to match the simulation deviation. This work demonstrated the Tl removal mechanism and provided insights into the accuracy of kinetic models on minor-radius heavy metal. Thus, this research may help promote the design of reactors, heavy metal removal rates, and flue gas purification technology selection.
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RSC Advances
·
2021
·Vol. 11
·期 14
·8375-8383
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IF 3.361
Kaijun Wang,Qifan Mao,Weimin Fei,Lingxin Kong,Xiaoyan Cao,Zhenggui Gu
Layered double hydroxides are a promising platform material which can be combined with a variety of active species based on their characteristic features. Silicon@P123-templated Ce-doped layered double hydroxide (SiO2@CeMgAl-LDH(P123)) composites were synthesized via a facile in situ co-precipitation method, and characterized by TEM, X-ray diffraction, FTIR, XPS, CO2-, etc. in detail. Meanwhile, the calcined powder (SiO2@CeMgAl-LDO(P123)) possessed an excellent core–shell structure and a high surface area inherited from the LDH structure, which led to an outstanding catalytic activity (99.7% conversion of propylene oxide, 92.4% selectivity of propylene glycol methyl ether) under mild reaction conditions (120 °C). Cerium oxide provides a large number of oxygen vacancies and significantly improves the medium basic strength of the material, which facilitates the selective ring-opening of PO. Furthermore, the introduction and removal of P123 make the cerium oxide uniformly dispersed on the LDH layers, providing more reaction sites for the reaction of methanol and propylene oxide. The core–shell structure prepared by the in situ co-precipitation method could solve the shortcomings of agglomeration of layered double hydroxides and prolong the catalytic life evidently.
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Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 33
·17174-17184
·
IF 11.301
Jianwei Fan,Xufei Niu,Wei Teng,Peng Zhang,Wei-xian Zhang,Dongyuan Zhao
Catalytic oxidation of formaldehyde (HCHO) is regarded as a promising strategy to eliminate this indoor air pollutant. The design of a highly active and cost-effective catalyst is still pivotal to improve the performance for HCHO oxidation. Herein, we report an Fe–Ce–O solid solution catalyst supported on ordered mesoporous silica (SBA-15) prepared by simple two-step impregnation–calcination, achieving highly efficient HCHO elimination at a low temperature. This strategy brings about the formation of small solid solution nanoparticles (7–12.9 nm) with good dispersion in confined spaces. Meanwhile, the catalysts possess large surface areas (∼500 m2 g−1) and pore volumes (0.5 cm3 g−1) with a pore size of ∼7.5 nm. The results show that Fe content and calcination temperature have great effects on the generation of oxygen vacancies in the catalyst, and further on the catalytic performance. The 20% FeOx-CeOx/SBA-15-350 catalyst displays superior catalytic activity with 65% and 94.9% conversion at 30 °C and 60 °C with a low concentration of HCHO (9.8 μg L−1), respectively, comparable to that for many reported precious metal catalysts. The high ratio of Ce3+ due to the formation of an Fe–Ce–O solid solution and highly dispersed active sites by the spatial confinement is favorable for more oxygen vacancy generation, which mainly contributes to the excellent performance. This work opens up an avenue to design highly efficient non-noble metal nanocatalysts for volatile organic compound (VOC) elimination.
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Journal of Central South University
·
2020
·Vol. 27
·期 4
·1176-1185
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IF 1.249
Jin Lin-feng,Chai Li-yuan,Song Ting-ting,Yang Wei-chun,Wang Hai-ying
Magnetic Fe 3 O 4 @Cu/Ce microspheres were successfully prepared by one-step solvothermal approach and further utilized to remediate toxic arsenic (As(III)) pollution. The effects of Cu/Ce elements co-doping on the crystal structure, catalytic oxidation and adsorption behaviors of magnetic microspheres were researched systematically. The results showed that with the aid of Cu/Ce elements, the grain size reduced, lattice defects increased, and the oxygen vacancies and surface hydroxyl groups were improved. Therefore, Cu/Ce elements endowed magnetic Fe 3 O 4 @Cu/Ce microspheres with excellent As(III) removal performance, whose maximum adsorption capacity reached 139.19 mg/g. The adsorption mechanism mainly involved catalytic oxidant co-adsorption. This research developed a feasible strategy for the preparation of high efficiency magnetic adsorbent to enhance the removal of As(III).
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JOURNAL OF RARE EARTHS
·
2020
·
IF 3.104
Baohuai Zhao,Rui Ran,Liu Yang,Xiaodong Wu,Zhichun Si,Duan Weng
A series of La 1– x Ce x MnO 3+ δ ( x = 0, 0.05, 0.1, 0.2, and 0.3) perovskites and Mn–Ce mixed oxides were prepared. Their physico-chemical properties were systematically characterized and the NO oxidation activities of the catalysts were investigated. The La 0.9 Ce 0.1 MnO 3+ δ has the best activity among all of the catalysts, with a maximum NO conversion of 85% at 300 °C. The characterization results indicate that the doping of Ce improves the properties of the perovskites in terms of the specific surface area, the average valence state of Mn ions, the number of reactive oxygen species and the NO x desorption behaviors. The Mn–Ce mixed oxide calcined at 500 °C shows a similar NO oxidation activity with La 0.9 Ce 0.1 MnO 3+ δ . However, the activity of the mixed oxide obtained at 750 °C decreases a lot, which results from the loss of active sites and active oxygen species.
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