CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Jiayou Liu,Xiaoxiang Huang,Lizhen Hu,Penglei Liu,Liuhu Jia,Keiko Sasaki,Zhongchao Tan,Hesheng Yu
Simultaneous avoidance of secondary air pollution and catalyst deactivation remains a challenge for existing photocatalytic removal of nitric oxide (NO). Herein, a photocatalysis-adsorption (P-A) heterojunction is synthesized for eco-friendly NO removal by facilely grinding Pd single atoms (Pd 1 ) anchored g-C 3 N 4 (48CN/Pd) with UiO-66-NH 2 (UION). Under visible-light irradiation, the 40UION-CN/Pd composite shows 93.91 % of NO removal efficiency with only 2.73 % of NO 2 emissions and negligible catalyst deactivation. The DeNO x index increases remarkably from −0.66 for 48CN/Pd to 0.86 for 40UION-CN/Pd. Furthermore, the synthesized P-A heterojunction efficiently removes NO from real flue gases produced by a domestic coal-fired stove and from SO 2 -rich flue gases. The mechanism exploration based on experimental investigations and density functional theory (DFT) calculations reveals that UION captures the NO 2 selectively produced by 48CN/Pd, simultaneously suppressing NO 2 emissions and refreshing active sites for NO photooxidation. Moreover, the results of X-ray photoelectron spectroscopy (XPS), charge density difference calculation, energy-resolved distribution of electron traps (ERDT) and in-situ Kelvin probe force microscopy (KPFM) reveal that the built-in electric field and Type-II heterojunction formed between 48CN/Pd and UION promote the separation of photogenerated carriers, enhancing the catalytic activity of the composite. This work provides an innovative strategy to avoid NO 2 emission and catalyst deactivation during photocatalytic NO removal.
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CHEMOSPHERE
·
2023
·
IF 8.8
Xiule Wang,Fanyong Yan,Ying Chen,Xinyi Bai,Yang Fu
Metal organic frameworks (MOFs) possess a large surface area, inherent porosity and high crystallinity . Nevertheless, they lack electron acceptors, which limit the exploitation of their photocatalytic properties. Carbon dots (CDs) known for excellent optical properties can serve as localized electron acceptors. As a novel hybrid nanomaterial , the structure of CDs@MOFs effectively facilitates charge separation and carrier transfer, bring about a marked improvement of photocatalytic activity. In this study, yellow-emission carbon dots (YCDs) were encapsulated within zirconium-based metal organic framework (UiO-66) via a dynamic adsorption method. Compared with blue carbon dots (BCDs), the YCDs@UiO-66 exhibited superior degradation performance. It demonstrates that incorporation of YCDs broadens the UV absorption range of UiO-66, thereby enhancing light utilization. The degradation efficiency of YCDs@UiO-66 was 92.6%, whereas UiO-66 alone achieved only 63.1%. Notably, the results of the radical quenching experiment and electron paramagnetic resonance (EPR) revealed that h + and •O 2 − played a prominent role in the photodegradation of tetracycline hydrochloride (TCH). This study highlights that the introducing YCDs in MOFs-mediated photocatalytic reactions is a viable strategy to improve catalytic efficiency.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Siyu Liu,Jianhua Zu,Gang Han,Xiaohan Pan,Yi Xue,Jingjie Diao,Qing Tang,Mingjie Jin
137 Cs is a radioactive pollutant in the production of wastewater from nuclear power plants. In this study, a rapid and simple in-situ synthesis new method was employed to prepare a novel AMP-functionalized UiO-66 composite material for the selective capture of 137 Cs from low-level radioactive wastewater. Characterization techniques such as SEM-EDS, FTIR, XRD, TG, and BET were used to confirm the successful loading of AMP on the surface of UiO-66. UiO-66/AMP showed a good removal effect in pH4-11. At pH7, the effects of different parameters, such as the initial Cs concentration, the ratio of the amount of adsorbent to the volume of solution, and the adsorption time were investigated. The adsorption efficiency is 96.7%, the maximum adsorption capacity is 94.9 mg/g and has fast adsorption kinetics (90% Cs + removal within 5 min). The adsorption data conformed to the pseudo-second-order kinetic model and Langmuir isotherm model, suggesting a monolayer homogeneous adsorption process. XPS helps confirm that the adsorption mechanism is the ion exchange between Cs + and NH 4+ ions. Particularly, in the adsorption experiments of 137 Cs, UiO-66/AMP demonstrated good selectivity (K d Cs : 5.8 × 10 3 ∼ 1.26 × 10 4 mL/g) towards trace Cs + in a mixed ion solution with a molar ratio of 1 (Cs): 2.18 × 10 15 (Na): 4.6 × 10 14 (K): 2 × 10 14 (Mg): 2 × 10 14 (Ca), indicating its potential for selective capture of 137 Cs from low-level liquid waste (LLLW).
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Journal of Materials Chemistry A
·
2023
·Vol. 12
·期 6
·3565-3574
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IF 11.9
Ling-Chan Tian,Geqian Fang,Yun Zhou,Wenjun Yu,Lin Li,Jin-Nian Hu,Haiyan Wang,Jin-Xia Liang,Chun Zhu,Xiaodong Wang,Jian Lin
Direct selective oxidation of methane (DSOM) to oxygenates under mild conditions is garnering increasing interest. UiO-66-H MOFs are effective for this reaction, while the active configuration of Zr-oxo nodes with adsorbed ˙OH species need further clarification from the atomic/molecular viewpoint. Here, we detect the evolution of the geometric and electronic structures of adsorbed oxygenic species on Zr-oxo nodes of UiO-66-H via the controlled ˙OH species. DFT calculations reveal a volcano-like curve relationship between the quantity of ˙OH species and the DSOM performance, which is further corroborated by experimental tests. Zroxo-˙OH is the main active configuration on Zr-oxo nodes of UiO-66-H at low ˙OH concentration, while it evolves to other oxygenic species (˙OOH, O2, and H2O) due to the self-reaction with the increase of ˙OH concentration, which leads to performance decrease. Furthermore, a critical descriptor of the p-band centers of O atoms in these oxygenic species on the Zr-oxo nodes is established, which can well represent the catalytic activity for the DSOM reaction.
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Biomaterials Science
·
2021
·Vol. 9
·期 7
·2647-2657
·
IF 6.843
Xiaojuan Wang,Xuejian Zhou,Kai Yang,Qiong Li,Rongxin Wan,Guoying Hu,Jin Ye,Yue Zhang,Jiahui He,Hanqing Gu,Yongfang Yang,Lei Zhu
In this study, UiO-66-NH2 metal–organic framework (MOF) nanoparticles with peroxidase and oxidase mimetic activities were incorporated into a chitosan (CS) matrix by a simple and environmentally friendly method. The UiO-66-NH2/CS composite membrane possesses the peroxidase mimicking activity in the presence of traces of H2O2, thus resulting in good antibacterial properties. Intriguingly, 30 min of UV pre-irradiation of the UiO-66-NH2/CS composite membrane, in the absence of H2O2, still leads to a good antibacterial activity. This was attributed to the oxidase mimetic activity and the peroxidase mimicking activity of UiO-66-NH2. In such a way, the side effects of direct exposure to UV irradiation and H2O2 can be avoided for wound-healing treatments. The antibacterial mechanism was further proved by antibacterial experiments, TMB·2HCl color development experiments, reactive oxygen species generation tests and electron spin resonance tests. As a potential medical antibacterial dressing, in vitro membranes were also investigated.
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JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Jiali Tang,Yingbi Chen,Minghu Zhao,Shixing Wang,Libo Zhang
A novel metal-organic framework (UiO-66-PTC) for efficient removal of Pb 2+ ions from wastewater has been prepared by using 4-phenyl-3-thiosemicarbazide as the modifier. Various characterizations showed that UiO-66-PTC was successfully synthesized. The absorption results showed that the maximum adsorption capacity of Pb(II) is 200.17 mg/g at 303 K and optimal pH 5. The adsorption kinetic follows the pseudo-second-order model and the adsorption isotherms fit the Langmuir model. This shows that Pb(II) is a single-layer adsorption on the surface of the adsorbent and the rate-controlling step is chemical adsorption . The thermodynamic results show that the adsorption process can proceed spontaneously, belong to the exothermic reaction . The adsorbent can selectively uptake lead ions from wastewater containing multiple interfering ions. After four adsorption and desorption cycles, the adsorption efficiency is still high. The adsorption mechanism of Pb(II) on the adsorbent is mainly through the chelation of Pb(II) with N and S atoms. These results indicate that UiO-66-PTC is an effective material for efficiently and selectivity removal of Pb(II) from solution, which is of practical significance.
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Journal of Cleaner Production
·
2021
·
IF 9.297
Zijie Wang,Yannan Jia,Weikun Song,Xiaoqin Li,Kai Xu,Zheng Wang
The removal of boron in desalinated seawater has always been one of the keys to restrict the use of desalinated seawater. For this reason, a composite adsorbent named UiO-66-NH 2 /GO was successfully prepared by a simple solvothermal method through this research. It is composed of graphene oxide and water-stable metal organic framework UiO-66-NH 2 , and for the first time as a boron adsorbent for the treatment of desalinated seawater. Various technologies were applied to systematically analyze the stability, structure, topography and chemical characteristics of the composite adsorbent. The relationship between the influencing factors and the adsorption effect was investigated, including the amount of adsorbent, contact time, initial concentration of boron, and pH of the boron solution. It is proved that the boron adsorption complies the pseudo-second-order kinetic model , the intra-particle diffusion model and the Langmuir isotherm model through the fitting of experimental results. The adsorption of boron by UiO-66-NH 2 /GO has both physical and chemical adsorption , including electrostatic attraction , covalent bond or electron transfer . The results of thermodynamic study pointed out the adsorption of boron is spontaneous and feasible. The response surface method was designed to improve the adsorption conditions of boron. The optimized adsorption conditions to reach 26.45 mg/g of boron adsorption were found to be at dosage of 75.03 mg/g with pH of 5 and temperature of 321.19 k. UiO-66-NH 2 /GO showed good removal ability for low concentration boron and good reusability . The above suggest that UiO-66-NH 2 /GO has the potential to be applied to desalinated seawater treatment.
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APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Xiaoxue Zhao,Linlin Sun,Xian Jin,Mengyang Xu,Shikang Yin,Jinze Li,Xin Li,Dong Shen,Yan Yan,Pengwei Huo
Z-scheme heterojunction can effectively separate photo-generated carriers and enhance photocatalytic activity of CO 2 reduction. In this work, we report indirect Z-scheme heterojunction of UiO-66-NH 2 /Cu 2 O/Cu, which achieves highly CO 2 photocatalytic conversion to CO. Among these, UiO-66-NH 2 /Cu 2 O/Cu-0.39 (U/C/Cu-0.39) displays the best activity with a CO yield of 4.54 μmol·g −1 ·h −1 , which is 37.8 times higher than that for UiO-66-NH 2 and 50.4 times higher than that for Cu 2 O. Cu not only acts as the electron conductor of the indirect Z-scheme heterojunction to promote the charge carrier transmission, but also acts as the active site of CO 2 reduction. The increase of active sites and the CO 2 adsorption capacity results in the superior photocatalytic performances.
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NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 34
·14379-14388
·
IF 3.288
Fenfen Zhu,Wei Xu,Xiao Li,Hao Meng,Yide Han,Junbiao Wu,Junli Xu,Yan Xu,Xia Zhang
Enzyme immobilization engineering is considered a valid strategy to improve the insensitivity of free enzymes to extreme conditions and thus extend their utilization in actual reactions. Although metal–organic frameworks (MOFs) are extensively applied as supports in enzyme immobilization, their separation from the liquid system after catalytic processes is problematic. In comparison, MOF-based membranes show more convenience in the subsequent solid–liquid separation. In this work, we constructed hybrid membranes by incorporating UiO-66 particles into porous polyvinylidene fluoride (PVDF) and then used them to immobilize lipase for the first time. Because of the strong affinity of UiO-66 towards lipase and the large cavity of PVDF, the hybrid membranes exhibited excellent immobilization ability towards lipase, and the resulting immobilized lipase showed an elevated operating temperature in the range of 40–70 °C with preserved activity and evidently improved thermal stability even after being stored at high temperatures for a definite time. The application of PVDF membrane makes the subsequent separation of the immobilized enzyme from the solutions easier. The immobilization kinetics, isotherm, and thermodynamics were analyzed in detail, and the immobilization mechanism was proposed. Furthermore, the immobilized lipase showed reusability and retained 48.2% of its initial activity after 7 cyclic reactions.
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RSC Advances
·
2020
·Vol. 10
·期 68
·41283-41295
·
IF 3.119
Ahmed S. Abou-Elyazed,Yinyong Sun,Ahmed M. El-Nahas,Ahmed M. Yousif
Recently, the incorporation of hydrophobicity on the surface of UiO-66(Zr) has received much attention due to the deactivation of hydrophilic active sites of UiO-66(Zr) upon water adsorption. In this work, we report UiO-66(Zr) catalysts with an assortment of surface hydrophobicities fabricated by the solvent-free method to elucidate the impact of the environment framing Lewis acid sites on their catalytic activity in the production of fatty acid methyl ester (biodiesel) via the esterification of fatty acids at room temperature with high selectivity (100%) and good recyclability. A detailed structural analysis of the materials by N2 sorption, FT-IR, SEM, XRD, water contact angle measurement, dynamic liquid scattering (DLS), NMR and TGA revealed the fabrication of stearic acid-grafted UiO-66(Zr) catalysts (10SA/UiO-66) with fine particle size and a highly hydrophobic network. 10SA/UiO-66(Zr) with enhanced hydrophobicity exhibited superior catalytic performance in the esterification of a fatty acid with a long alkyl chain compared with conventional solid acid catalysts and even liquid acid catalysts. Detailed kinetic studies corroborated that the adsorption of lipophilic acids at the Lewis acid sites besides the enhancement of wettability between the reactants was facilitated by the hydrophobic environment, thus significantly motivating the esterification reaction at room temperature. Furthermore, 10SA/UiO-66(Zr) showed good catalytic activity in the esterification of oleic acid in the presence of water (∼10% in the light of acid weight).
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CHEMICAL PHYSICS
·
2021
·
IF 2.348
Xingchang Tang,Yongwei Luo,Zhijian Zhang,Wanwu Ding,Dexue Liu,Jingchuan Wang,Li Guo,Ming Wen
The high surface areas and tunable properties of Zr-based MOFs make them as attractive materials for gas capture, storage, and separation. In this work, UiO-66, one kinds of Zr-based MOFs, functionalized by single or binary –NO 2 and –NH 2 groups are synthesized. Water adsorption ability and hydrophilicity of UiO-66 and functionalized UiO-66-X were investigated. It is found that surface area of UiO-66 is decreased after introducing functional groups, while hydrophilicity of UiO-66 increased after functionalized with –NO 2 and –NH 2 . Therefore, after balance the effects of surface area and hydrophilicity, UiO-66-NH 2 shows the best water adsorption propriety.
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EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
·
2020
·Vol. 2020
·期 10
·833-840
·
IF 2.529
Ruiping Wei,Jingdeng Fan,Xumin Qu,Lijing Gao,Yuanfeng Wu,Zongqi Zhang,Feng Hu,Guomin Xiao
Graphical Esterification of levulinic acid with ethanol was catalyzed by the cooperative effects between the Lewis acid sites offered by unsaturated Zr 6 nodes and Brønsted acid sites supplied by OH in defective UiO-66 MOFs with high defect density, which was tuned by precursor ratios and modulators. Due to their high stabilities and tunable defects, zirconium terephthalate UiO-66 type metal organic frameworks (MOFs) have been promising catalysts in many catalytic reactions. The catalytic activity of UiO-66 MOFs is significantly affected by the density of defects and hydroxyl groups bonded to Zr 6 nodes, which can be tuned by modulators. In this work, a series of defective UiO-66 were synthesized via tuning the ratio of H 2 BDC/Zr and adding monocarboxylic acids with different chain length as modulators. The synthesized UiO-66 MOFs were characterized by powder X-ray diffraction, N 2 physisorption, IR and 1 H NMR spectroscopy, scanning and transmission electron microscopy. Esterification of levulinic acid with ethanol was selected to reveal the influence of modulators, defects and hydroxyl groups. The results showed that UiO-66 with 0.5 of H 2 BDC/Zr ratio and lauric acid as the modulator owned excellent catalytic activity. The cooperative effects, between the Lewis acid sites offered by unsaturated Zr 6 nodes and Brønsted acid sites supplied by OH, has been revealed to have a significant influence on the catalytic activity.
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