DIAMOND AND RELATED MATERIALS
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2023
·
IF 4.1
Lin Chai,Yequn Liu,Wenjun Yan,Na Teng,Hongyan Li,Yongqin Qi,Haoliang Huang,Xiaojing Cui,Xianglin Hou,Tiansheng Deng
It is of fundamental and industrial interest to develop a facile method to modify the graphene sheets with heteroatoms such as oxygen (O) and nitrogen (N). Herein, the O and N atoms were discovered to be grafted onto the edges of graphene sheets during the simple grinding process with solvent in air or N 2 atmosphere. By combining X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscope (HRTEM), energy dispersive X-ray spectrometer (EDS), electron spin resonance spectroscopy (ESR) and H 2 O 2 experiments, we show where the O and N atoms were grafted and how the modification of graphene with O and N atoms occurred. The results showed that the O atoms of air and N atoms of solvent molecules could be bonded to the edges of graphene sheets during the grinding process, which followed the radical reaction mechanism.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Huahao Wang,Yaping Ding,Mengjia Ning,Miao Yu,Wenji Zheng,Xuehua Ruan,Yuan Xi,Yan Dai,Hongjing Liu,Gaohong He
Metal organic frameworks (MOFs) with appropriate pore size and sufficient CO 2 -philic groups are required to improve the mixed matrix membranes (MMMs)-based CO 2 capture. Herein, NH 2 -CPL-1 is designed for capture by utilizing amino pyrazine instead of pyrazine in CPL-1. The introduced CO 2 -philic amino groups together with rich hydroxyl and carboxyl groups in CPL-1 could improve the selective adsorption of CO 2 , enhancing the solubility selectivity. At the meantime, after the introduction of amino-functional, the pore size of NH 2 -CPL-1 is decreased from 0.93 nm of CPL-1 to 0.85 nm, which is beneficial for the screening of CO 2 over N 2 . As a result, the CO 2 separation performances of MMMs could be promoted greatly under the action of NH 2 -CPL-1. MMM with NH 2 -CPL-1 of 10 wt.% exhibited the best CO 2 separation performance, with CO 2 /N 2 selectivity of 85 and CO 2 permeability of 104 Barrer at 25 °C and 0.4 MPa. Compared with the CPL-1/Pebax-10 wt.% MMM, it was increased by 9.5 % and 13.3 %, respectively. This satisfactory CO 2 separation performance surpasses those of most reported other MOFs based MMMs, which is attributed to the facilitated CO 2 transport and pore size screening from the introduced amino groups. This is also confirmed by the improvement of diffusion selectivity and solution selectivity. The proposed NH 2 -CPL-1 shows great prospect as filler for enhanced MMMs-based CO 2 capture.
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Advanced Materials Interfaces
·
2023
·Vol. 10
·期 12
·2202524
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IF 5.4
Lei Wang,Xianying Bai,Yawei Gu,Xinxin Shi,Shilong Wang,Jingxian Hua,Rujing Hou,Chongqing Wang,Yichang Pan
2D metal–organic frameworks are attractive filler in mixed matrix membranes (MMMs) due to the high aspect ratio and contact opportunity at the filler–polymer interface. However, their alignment in polymer matrix remains a challenge to fully play their functions. Herein, to our best knowledge, for the first time, the facile synthesis of KAUST-7-NH 2 (KAUST, King University of Science and Technology) nanoplate is reported with 1D channels with an aspect ratio greater than 30. The nanoplates are incorporated and aligned in the 4,4′-(hexafluoroisopropylidene) diphthalic anhydride-2,4-diaminomesitylene (6FDA-DAM) polymer matrix under the shear force with a filler loading up to 50 wt%. The large difference in adsorption abilities between CO 2 and CH 4 from the (001)-oriented KAUST-7-NH 2 nanoplate-based MMMs and the favorable interaction at the filler–polymer interface contribute to the excellent CO 2 /CH 4 separation performance. The resultant membranes show CO 2 /CH 4 selectivity with 66.2% enhancement (surpassed 2008 Robeson upper bound), antiplasticization up to 17 bar, and long-term stability up to 240 h indicating its good potential for natural gas treatment.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2022
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IF 5.895
Tong Zhou,Xue Xia,Heping Cui,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho
The intervention of cysteine (Cys) on the formation of 2,3-butanedione and pyrazines was evaluated during the thermal processing of the alanine-xylose Amadori compound (AX-ARP). With the involvement of Cys, the competitive formation of 2,3-butanedione and pyrazines was induced. The formation of 2,3-butanedione in the AX-ARP/Cys model was suppressed due to the inhibitory effect of the precursors of 2,3-butanedione like deoxypentosones, while the added Cys in the AX-ARP/Cys model competed with the recovered alanine (Ala) to capture glyoxal and methylglyoxal to make up for the absence of pyrazines in the AX-ARP model at an initial pH value of 7. The content of pyrazines increased from 0 up to 16.48 μg/L (120 °C, 120 min). Exogenous Cys itself showed lower reactivity with 2,3-butanedione through the Strecker degradation reaction; while the pH was increased to 8, the degradative products of Cys were facilitated to consume the residual 2,3-butanedione giving rise to the formation of 2,4,5-trimethylthiazole at 120 °C. It was the degradative products of Cys that accelerated the reaction for consumption of 2,3-butanedione rather than Cys itself. Additionally, the inhibitory effect of Cys on 2,3-butanedione formation was weakened under a basic condition, while the promotional effect on the formation of pyrazines was further boosted. With more Cys participating in the process of AX-ARP thermal degradation, the formation of 2,3-butanedione was further inhibited, while the yields of pyrazines were increased.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Runfei Xu,Haoyang Huang,Wenjing Wang,Lei Ding,Qiang Lin,Jinbing Li,Yu Zhang,Yongsheng Han,Jianguo Wang,Xiaohua Lu
We report an approach of direct production of H 2 O 2 from water by applying altering potential in the electrocatalysis. By switching potentials periodically between positive to negative, oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) occurs sequentially on a single electrode loaded catalysts, which leads to the reduction of the newly-formed OER active species, forming H 2 O 2 directly. The H 2 O 2 production is dependent on the time and potentials of OER and ORR, which is optimized in this study. Besides, a waiting time is set after each period to let H 2 O 2 diffusion from the catalyst surface. Different catalysts are employed to test the feasibility of this approach, including glassy carbon, graphene oxide, nickel particles, nickel foam, and palladium particles. All these catalysts result in the production of H 2 O 2 at various reaction rates. Ni offers the highest H 2 O 2 productivity. With the prolonging of the reaction time, the decomposition of H 2 O 2 occurs on the surface of Ni catalysts, which is inhibited by the addition of Zn into the catalysts. The in-situ generated H 2 O 2 is used for partial oxidation of propylene by passing propylene into the porous electrode during the reaction, which lead to the formation of dimethyl ether and adipic acid. This study shows a new route of the direct synthesis and utilization of H 2 O 2 for the generation of valuable chemicals.
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ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Jiamin Li,Haochen Shen,Chenxi Ma,Hao Zhang,Peng Luo,Junteng Chen,Manman Mu,Xiaohong Yin
Electrocatalytic reduction of CO 2 (CO 2 RR) into value-added chemicals is a promising approach to alleviate environmental issue, but the efficiencies of electrocatalysts are limited by the poor conductivity, low current density and large overpotential. Herein, two-dimensional bimetallic porphyrin-based conjugated cobalt MOF (Co-(Co+Cu) PMOF) is deposited on g-C 3 N 4 nanosheets to construct g-C 3 N 4 @Co-(Co+Cu)PMOF which enhances electron transfer from g-C 3 N 4 to Co-(Co+Cu)PMOF. Benefiting from its larger capacitance and faster charge transfer rate than g-C 3 N 4 and Co-(Co+Cu)PMOF, g-C 3 N 4 @Co-(Co+Cu)PMOF-50% exhibits superior catalytic activity with a high Faradaic efficiency of CO (97.8%) and large current density of -2.1 mA•cm −2 at -1.4 V compared with pristine Co-(Co+Cu)PMOF and other porphyrin-based MOF analogues. The high performance might ascribe that Co centers in porphyrin rings acquire more electrons to activate CO 2 which can be converted to intermediate *COOH through evidences from the experimental results and theoretical calculations. This work provides a new insight into the rational design of electrocatalysts for the CO 2 RR using porphyrin-based conjugated MOFs.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Rujing Hou,Shilong Wang,Lei Wang,Chang Li,Huan Wang,Yingtian Xu,Chongqing Wang,Yichang Pan,Weihong Xing
The trade-off relationship between permeability and selectivity as well as plasticization issues have largely impeded the advancement of membrane technology. Mixed-matrix-membranes (MMMs) with the incorporation of fillers into the polymer matrix is one promising method to deal with these challenges by carefully tuning their chemical properties. Compared with nanoparticles, the counterpart of nanosheet has a larger external surface area with a tendency to have closer contact with a polymer matrix to form a defect-free membrane at higher loading. This work successfully synthesized a high aspect ratio (30/1) of KAUST-8 nanosheets with high CO 2 uptake (60 cm 3 /g). This enables an optimal loading of 30 wt.% in the CO 2 -attractive crosslinked poly(ethylene oxide) (XLPEO) membrane and results in the simultaneously enhanced CO 2 permeability and CO 2 /N 2 selectivity with 280 % and 30 % up, respectively in the mixed gas permeation measurements (50/50 vol.). The resultant membrane performance surpassed the 2008 Robeson upper bound. Meanwhile, the stabilized MMM performance of up to 6 bar and high thermal stability of up to 350 °C bring extra benefits to the KAUST-8-based XLPEO membrane for post-combustion flue gas treatment.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2022
·Vol. 49
·期 1
·241-252
·
IF 3.134
Xing Qianqian,Zhao Jiancheng,Zhu Yulei,Hou Xianglin,Wang Yingxiong
5-Chloro-2-pentanone (5C2P) and its derivatives are widely utilized in the pharmaceutical and agrochemical industry. A new catalytic approach was proposed to convert 3-acetyl-1-propanol to 5C2P using bis(trichloromethyl)carbonate (triphosgene, BTC) as the efficient chlorine source. Various qualitative and quantitative nuclear magnetic resonance techniques ( 1 H, 13 C NMR), especially 1D selective gradient total correlation spectroscopy (Sel-TOCSY) and 2D heteronuclear single quantum correlation ( 1 H- 13 C HSQC) were used in the process. The reaction conditions, such as temperature, time, mole ratio, solvent as well as initiator were optimized. Experiment results showed that the yield of 5C2P reached a maximum of 97.93% in 1,2-dichloroethane at 80 °C after 2 h under the initiation of N,N-dimethylacetamide, and the optimal molar ratio of 3-acetyl-1-propanol to BTC was 1:0.4. The reaction mechanism was proposed and confirmed accordingly. Interestingly, an intermediate product of 1-(dimethylamino)ethyl carbonochloridate was observed, and its chemical structure was characterized by both Sel-TOCSY and 1 H- 13 C HSQC. This study enriched the catalytic reaction ways for the preparation of 5C2P.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2023
·
IF 6.1
Tong Zhou,Xue Xia,Heping Cui,Yun Zhai,Foxin Zhang,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho
The influence of pH was studied on volatile flavor formation during thermal treatment of an Amadori rearrangement product (ARP) with or without the addition of cysteine (Cys). The formation of thiols and sulfides or 2-acetylthiazole and pyrazines induced by Cys during thermal degradation of ARP was pH-dependent. At low pH levels, the hydrolysis of Cys to hydrogen sulfide (H2S) was promoted, giving rise to the increase of thiols and sulfides with an obvious meaty aroma. However, alkaline conditions were beneficial for enhancing the cyclization or transformation of imine to the enol structure, which strengthened the formation of 2-acetylthiazole and pyrazines with a roasted and nutty aroma. The imine was derived from the nucleophilic addition of Cys and methylglyoxal (MGO) and subsequent decarboxylation. At pH 8, Cys-induced variation of the flavor profile was weakened during thermal degradation of ARP. Accordingly, the combinational effect of pH and added Cys could be beneficial for achieving the desirable flavors during thermal processing of ARP.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Gang Li,Ruiyang Tan,Xiangcheng Lu,Xinyu Zhang,Chengcheng Zhang,Bohong Gao,Yuting Zhou,Ke Chen,Ping Chen,Xinyi Wang
Chemical composition and morphological optimization are both effective strategies for constructing excellent electromagnetic wave absorption (EMWA) materials. While efficient EMWA materials derived from both metal-organic frameworks (MOFs) and MXenes have been extensively studied, composites derived from the Hofmann framework with MXene have not been reported. In this study, we employed a Hofmann framework ([Fe(pz)Ni(CN) 4 ], pz = pyrazine) and MXene (Ti 3 C 2 T x ) to create new MXene@Hofmann (MH1 and MH2) composites, using a simple co-precipitation method with two different contents of [Fe(pz)Ni(CN) 4 ]. The FeNi/C/TiO 2 composites with a multi-layered structure inherited from MXene were prepared by annealing the MXene@Hofmann composites at 500, 600, and 700 °C, resulting in the formation of MH1-500/600/700 and MH2-500/600/700 composites. Their compositions, morphologies, electromagnetic parameters, and EMWA performances were characterized. For the composites with a high [Fe(pz)Ni(CN) 4 ] content, MH2-600 has a minimum reflection loss ( RL min ) value of −30.63 dB at a thickness of only 1.8 mm and the broadest effective absorption bandwidth (EAB) of 3.90 GHz at 2.0 mm, while MH2-700 exhibits superior EMWA performance with an RL min value of −34.34 dB at 1.9 mm and an EAB value of 4.96 GHz at 2.1 mm. Their impressive EMWA performance might be attributed to the synergistic dielectric loss and magnetic loss and also the impedance matching from the reasonable ratio of the magnetic and dielectric components. This work demonstrates an effective strategy for constructing EMWA materials from the Hofmann framework and MXene.
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ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Zishang Tian,Qi Zhao,Xingchen Liu,Yingxiong Wang,Jie Zhao,Yuqi Wang,Xianglin Hou
Aromatic polyimide (PI) is characterized by rigid chains and strong interchain interactions, resulting in poor solubility and non-melting of polymers, so chemical recovery of PI is challenging. Herein, ethylenediamine (EDA) was successfully used for the aminolysis of PI on the surface of flexible printed circuit boards (FPCBs). The PI can be completely degraded at 50 °C for 40 min at a revolution speed of 200 rpm, and the epoxy adhesive and flexible copper clad laminate sheet were separated by simple filtration. The degradation mechanism of PI was proposed and verified by the density functional theory (DFT) method. Intermolecular hydrogen bonding and the vicinal amino moiety of EDA play an important role in activating nucleophiles. DFT calculations show that the formation of the six-membered ring transition state is the rate-determining step during the breaking of the amide bonds. The Gibbs activation energy and the Gibbs reaction energy are 22.90 and 11.73 kcal/mol, respectively. This study provides guidance for the degradation of PI and the recovery of FPCBs.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Xiao-Gang Jin,Xiao-Kang Liang,Jia-Hao Liu,Jia-Wei Mo,Tian-Xiang Ren,Xiao-Hua Ma,Zhen-Liang Xu
High-performance nanofiltration membrane is of great importance to alleviate the worldwide freshwater crisis. Recent studies have shown that the performance of nanofiltration membranes can be enhanced by optimizing the properties of the substrates. Substrates with large pores are favorable to mass transfer but difficult to prepare highly selective polyamide layers on them by interfacial polymerization reaction. Here we employed porous two-dimensional (2D) aluminum-metal organic framework (Al-MOF) nanosheets to tune the commercial Nylon microfiltration substrate, and then prepared polyamide nanofiltration membranes by interfacial polymerization. 2D Al-MOF nanosheets were chosen for the tuning material except for their obvious advantages of easy synthesis and structural stability, the most important thing was their high porosity, which provided additional water transport channels. The morphologies as well as the separation properties were analyzed systematically. The best-performing Nylon-2.5 TFC membrane achieved an ultrahigh permeability (42.4 L m −2 h −1 bar −1 ), 13 times that of a control (PES-0) TFC membrane prepared on commercial PES substrate under the same interfacial polymerization conditions while ensuring the high rejection of Na 2 SO 4 (97.0%). Our work provides insights for optimizing substrate properties to prepare high-performance nanofiltration membranes.
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