SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Qingping Xin,Yucheng Pan,Chao Zhang,Lei Zhang,Chensheng Dong,Ligang Lin,Lizhi Zhao,Hui Ye,Yuzhong Zhang
The CH 4 /N 2 high-efficiency membrane separation technology is capable of effectively enriching CH 4 from natural gas, and holds great potential for application in the fields of biogas purification and natural gas pipeline leak detection. However, preparing high-performance separation membranes is challenging due to the similarity between CH 4 and N 2 molecules. To enhance the CH 4 /N 2 separation performance, block polyetheramide copolymer (Pebax)/EVA blended membranes were fabricated in this study. Additionally, a novel gas leakage detection tube was prepared. The EVA14 (14 wt% VA) membrane exhibits an optimal transport-facilitated channel among a series of pure EVA membranes, resulting in a CH 4 permeability of 21.41 Barrer and CH 4 /N 2 selectivity reaches 1.80 under mixed-gas feed conditions at 35 °C. The CH 4 permeability of Pebax/EVA (30 wt%) reaches 120.5 Barrer by physical blending, and the CH 4 permeability is increased by 191 % in comparison with pure EVA14 membrane. The Pebax/EVA (10 wt%) membrane exhibits the optimum CH 4 /N 2 selectivity, and compared with pure EVA membrane increased by 35.5 %. EVA and Pebax polymers are blended for the first time for CH 4 /N 2 separation, and the blending of block polyetheramide copolymer intensifies the membrane's separation performance comprehensively. The natural gas leak detection tube was fabricated with a membrane, offering a new and efficient CH 4 /N 2 separation strategy.
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CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Feng Xu,Ying Yu,Jian Yan,Qibin Xia,Haihui Wang,Jing Li,Zhong Li
An ultrafast synthesis method is developed for the preparation of composites of graphite oxide and HKUST-1, GrO@HKUST-1. Fast synthesis of GrO@HKUST-1 composites can be quickly achieved at room temperature within 1 min. The synthesized composites were characterized by XRD, SEM, N 2 adsorption, FTIR and TGA. The isotherms of CO 2 and N 2 on the as-synthesized materials were measured and the isosteric heats of CO 2 adsorption were estimated. The CO 2 /N 2 adsorption selectivities were predicted by means of ideal adsorbed solution theory (IAST). Results show that the GrO@HKUST-1 composites have higher BET surface area and pore volume than the parent HKUST-1. The CO 2 adsorption capacity of 2GrO@HKUST-1 (2% of GrO) is up to 9.02 mmol/g at 1 bar and 273 K, giving an increase of 32% in comparison of the parent HKUST-1. The isosteric heat of CO 2 adsorption on 2GrO@HKUST-1 is slightly higher than that of HKUST-1, suggesting the stronger interaction between CO 2 molecules and 2GrO@HKUST-1. The CO 2 /N 2 adsorption selectivity of 2GrO@HKUST-1 is significantly enhanced over pristine HKUST-1. At 1 bar, the CO 2 /N 2 adsorption selectivity of 2GrO@HKUST-1 is up to 186, while that of parent HKUST-1 is only 103. This rapid room temperature synthesis route is promising for new MOF-based composites.
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CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Zhiqiang Zhang,Yongpeng Xu,Wenxin Shi,Wei Wang,Ruijun Zhang,Xian Bao,Bing Zhang,Li Li,Fuyi Cui
The Pd–Cu/γAl 2 O 3 catalysts were prepared by impregnation method and introduced into the cathode chamber of a divided electrochemical denitrification cell with two graphite plates as the cathode and anode, to enhance the nitrate removal efficiency and N 2 selectivity. The Pd–Cu/γAl 2 O 3 catalysts were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), specific surface area measurements (BET) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). In the rationally designed electrochemical-catalytic (ECC) system, the as-prepared catalyst could significantly enhance the nitrate degradation rate to 1.08 mg/L at current density of 10 mA/cm 2 , which was approx. 2.5 times compared with the electrochemical (EC) system without catalysts adding in. Additionally, a higher nitrogen selectivity of 80.37% was obtained under the same experiment condition. The improved performances were likely due to the presence of a catalytic reduction reaction of nitrate with the appropriate amount of hydrogen generated by electrolysis as reductant. Significantly, the current efficiency was calculated and enhanced value of 20–40% (depended on current density) was obtained in the ECC process with a catalyst content of 1.0 g/L.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2015
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IF 2.037
Qiaobei Dong,Yan Sun,Wei Su,Jia Liu
The use of hydrate formation in porous media is an effective method for gas storage and separation. The equilibrium isotherms of CH4 and N2 in CMK-3, a mesoporous carbon material, were measured under different tetrahydrofuran (THF) concentrations and temperatures. The higher is the temperature required, the greater is the formation pressure needed, but the presence of THF significantly reduces the hydrate formation pressure. When THF exists, both CH4 and N2 form structure II (sII) hydrate; however, the amount of hydrate generation is lower than the theoretical value. As the operating pressure increases, some of the sII CH4 hydrate may transform into structure I (sI) and the amount of hydrate generation increases. The desorption isotherms showed that the gas hydrate decomposed completely when the operating pressure was below the hydrate decomposition pressure. In addition, it is feasible to separate gas mixtures via hydrate formation using the different gas hydrate formation pressures.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2014
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IF 2.235
Jing-Xiu Hu,Hao Shang,Jin-Gui Wang,Liang Luo,Qiang Xiao,Yi-Jun Zhong,Wei-Dong Zhu
Melamine based microporous organic polymers (MBMOPs) have been prepared via a one-pot polymerization using the Schiff base reaction. Various techniques such as FT-IR, Ar adsorption, SEM, TEM, and TG have been used to characterize the textural structure, porosity, and stability of the synthesized MBMOPs. The adsorption isotherms of CO2 and N2 on MBMOPs have been accurately measured at pressures up to 118 kPa and different temperatures. Ascribed to the specific affinity of amine groups for CO2, the robust microporous MBMOPs display excellent CO2 adsorption performance in terms of both capacity, up to 2.8 mmol g–1 at 273 K and 118 kPa, and selectivity over N2. Dual-site Langmuir (DSL) or single-site Langmuir (SSL) model describes well the equilibrium data for the adsorption of CO2 or N2 on MBMOPs, respectively. The binary gas adsorption isotherms predicted by the ideal adsorbed solution theory (IAST) show that the prepared MBMOPs exhibit very high selectivities for CO2 over N2, up to 83.7, for equimolar mixtures of CO2 and N2 at 298 K and 100 kPa. The dynamic CO2 adsorption capacity and selectivity against N2 over MBMOPs have been experimentally investigated by breakthrough column technique at 1 bar and 298 K, indicating that a complete separation is available. Remarkably, CO2 capture–regeneration experiments indicate that MBMOPs can be easily regenerated by only purging with He or N2 rather than by raising the temperature, suggesting that MBMOPs are promising candidates of pressure swing adsorption (PSA) adsorbents for the separation of CO2–N2.
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APPLIED SURFACE SCIENCE
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2024
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IF 6.3
Huiyuan Cheng,Jingwei Hu,Zihan Liu,Guangping Lei,Guojun Xi,Yayun Zhang,Hantao Liu,Xuhuan Guo,Huiyun Ren
Developing novel adsorbents for CO 2 capture and separation offers an efficient approach to relieving global environmental problems. To promote CO 2 capture from flue gas, novel Cr 3 O@MIL-101(Cr) composites was synthesized through packing [Cr 3 O(HCOO) 6 (H 2 O) 3 ]NO 3 into MIL-101(Cr) cages. The resultant composite Cr 3 O@MIL-101(Cr) presents higher CO 2 uptakes at lower pressure ranges, benefiting from the increased content of unsaturated Cr(III) ions and micropores relative to MIL-101(Cr). Meanwhile, IAST selectivity for CO 2 /N 2 mixture reached 50.2 under standard temperature and pressure, outperforming most of the reported materials. Further GCMC simulations reveal that the synergistic effect of [Cr 3 O(HCOO) 6 (H 2 O) 3 ] + , NO 3 − and MIL-101 (Cr) could effectively facilitate the interactions with CO 2 molecules and hinder N 2 molecules from approaching the optimal adsorption sites. Thus the [Cr 3 O(HCOO) 6 (H 2 O) 3 ]NO 3 encapsulated MIL-101(Cr) can be recommended as a promising adsorbent for superior CO 2 /N 2 separation.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2024
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IF 20.2
Xiaoyue Chen,Guangmin Ren,Yaru Wang,Zizhen Li,Zisheng Zhang,Xiangchao Meng
The synthesis of ammonia through electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is a presumable strategy. However, it still faces the problems of poor activity and low Faradic efficiency, so the development of efficient, stable and highly selective catalysts is of the importance. Molybdenum disulfide (MoS 2 ) materials are widely used in NRR reactions owing to good electrical conductivity and abundant active sites, but the edge active site is the dual active site of NRR and competitive hydrogen evolution reaction (HER). Encouragingly, the strong interaction between elements in the P-block and N 2p orbitals results in excellent performance in adsorbing and activating nitrogen. Meanwhile, the partial occupation of p-orbitals by elements in the P-block also leads to poor HER activity. Herein, we introduced the P-block element Bi into 1 T-MoS 2 and prepared Bi 2 S 3 /MoS 2 composite. Taking advantage of the high conductivity of 1 T-MoS 2 and the N 2 adsorption and activation advantages of Bi element, an ammonia yield rate of 54.64 µg h −1 mg −1 cat. and a high Faradic efficiency of 58.56 % were obtained. In addition, the active site and the evolution pathway of N 2 reduction were investigated by in-situ infrared spectroscopy measurements and density functional theory (DFT). The in-situ infrared spectroscopy measurement results manifested the presence of the main intermediate transition state during the reduction of N 2 to NH 3 . The calculation results indicated that N 2 had the best adsorption on the introduced P-block element Bi, and the entire NRR reaction process followed an alternating pathway. This study reveals the synergistic effect of P-block elements and transition metal-based electrocatalytic materials on nitrogen reduction to ammonia synthesis .
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ChemSusChem
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2024
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IF 7.5
Yun Liu,Guijiang Liu,Lichuan Chen,Song Hong
Graphical Nitrogen-doped iron-based nanoparticles (Fe NPs-N@C), characterized by the presence of Fe8−N2 active sites, are synthesized to exhibit oxidase-like activity, facilitating the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to yield the blue product, oxTMB. Designing metal nanoparticles with oxidase-mimicking capabilities has garnered significant attention due to their promising attributes. However, understanding the intricate catalytic mechanisms underlying these nanoparticles poses a formidable challenge. In this study, a straightforward pyrolysis procedure was employed to synthesize nitrogen-doped iron-based nanoparticles (Fe NPs-N@C) with Fe8−N2 serving as active sites. The confirmation of these sites was thoroughly confirmed through density functional theory (DFT) calculations complemented by experimental validation. The resulting Fe NPs-N@C nanoparticles, averaging 5.45 nm in size, exhibited excellent oxidase-mimicking activity, with v max =1.11×10 −7 M s −1 and k m =1.67 mM, employing 3,3′,5,5′-tetramethylbenzidine as a substrate. The oxidation pathway and catalytic mechanism of Fe NPs-N@C involved 1O 2 ⋅ radicals, validated through electron paramagnetic resonance analysis and DFT calculations. Furthermore, Fe NPs-N@C/TMB system was devised for ascorbic acid and nitrite quantitative detection. This method demonstrated the capability to detect ascorbic acid within concentrations ranging from 1 to 55 μM, with a limit of detection (LOD) of 0.81 μM, and nitrite within concentrations from 1 to 160 μM, with a LOD value of 0.45 μM. These findings offer a comprehensive understanding of the catalytic mechanisms of Fe NPs-N@C nanoparticles at the atomic level, along with its potential for colorimetric sensor in future.
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高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2024
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IF 11.2
Chi Cao,Jinshuo Li,Linfeng Zhang,Yang Hu,Lin Zhang,Wensheng Yang
Herein, a new type of two-dimensional (2D)/2D Ti 3 C 2 /TiO 2 heterojunction was developed for efficient photocatalytic nitrogen reduction reaction (NRR), in which TiO 2 nanosheets (TiO 2 Ns) were designed as the main catalyst, while Ti 3 C 2 MXene served as the co-catalyst. Experimental and theoretical results revealed that Ti 3 C 2 MXene introduced electron-rich unsaturated Ti sites, serving as highly active sites for both the adsorption and activation of N 2 on the Ti 3 C 2 /TiO 2 heterojunction. Furthermore, the 2D/2D Ti 3 C 2 /TiO 2 heterostructure greatly promoted the directional separation and transfer of charge carriers, facilitated by the internal electric field. This structural feature enabled the spatial separation of the N 2 reduction and H 2 O oxidation half-reactions on the distinct surfaces of Ti 3 C 2 (001) and TiO 2 (001), consequently reducing the reaction energy barrier for each respective process. The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photocatalytic NRR activity. As a result, the optimized Ti 3 C 2 /TiO 2 heterojunction exhibited a high NH 3 production rate of 24.4 μmol g -1 h -1 in the absence of sacrificial agents, representing a remarkable 12.8-fold increase compared to individual TiO 2 Ns. This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism underlying surface active sites in the photocatalytic NRR process.
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POLYMER
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2024
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IF 4.1
Zhe Cheng,Pei Wang,Yunlong Sun,Zhipeng Wang,Guangyuan Zhou
Gas separation membranes have a wide range of applications in industry, and there are two important factors in judging membrane standards permeability and selectivity. How to improve the selectivity of gas separation membranes while improving permeability is a challenge. In this study, poly (aryl ether sulfone) (PES) block copolymers were synthesized from fluorine-terminated polysulfone (PSF–F) and hydroxyl-terminated cardo PES containing phenyl substituted isoindolinone side group (PES-PPI-OH). Large side groups can enlarge the free volume and hinder chain movement to improve gas permeation behavior. Solvent-induced microphase separation of block copolymers by casting membranes with solvent benzyl alcohol (BA) can improve selectivity. The PSF- b -PES-PPI (10:10) BA membrane maintain good mechanical properties and tensile strength up to 93 MPa which compared to random polymer membrane rises to 14 MPa. Gas permeation at 23 °C showed that the O 2 /N 2 selectivity of PSF- b -PES-PPI (5:15)BA membrane was 10.6, which was the 2008 Robeson upper bound. Thus, poly (aryl ether sulfone) materials showed great potential application for O 2 /N 2 separation.
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CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Zixian Qin,Yuxiu Sun,Zhengqing Zhang,Chenxu Zhang,Chi Tang,Chenxu Geng,Zhihua Qiao
Oxygen/nitrogen (O 2 /N 2 ) separation is of great importance but faces huge challenges owing to their similar molecular size and close polarity. In this work, we construct a polymer of intrinsic microporosity (PIM-1) based mixed matrix membrane (MMM) for efficient O 2 /N 2 separation by using ZIF-8 as the sieving filler along with surface modification of o-carborane (o-CB) to strengthen selective N 2 adsorption fixation as well as polymer-filler interfaces. Markedly, the o-CB on the outer surface of ZIF-8 not only affords the requisite interfacial compatibility in molecular sieving MMMs, but also increases the diffusion difference between O 2 and N 2 by the preferential adsorption with N 2 molecules. This synergistic effect of molecular sieving and adsorption inhibition achieves efficient O 2 /N 2 diffusion differential separation. As expected, the optimal membrane with o-CB-ZIF-8 loading of 35 wt% exhibits an O 2 permeability of 796.5 Barrer and a mixed O 2 /N 2 selectivity of 8.9 with O 2 /N 2 (20:80, vol.) mixtures, exceeding the latest 2015 upper bound limits. Moreover, the according membrane module with o-CB-ZIF-8 loading of 20 wt% also displays moderate O 2 permeability of 391.7 Barrer and O 2 /N 2 selectivity of 5.5 under pressure of 1 bar. This work may provide a feasible platform for designing high-performance MOF-based membranes in air separations.
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FOOD CHEMISTRY
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2025
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IF 9.8
Cong Jiang,Zong Meng
The development of green and efficient catalytic systems is crucial for sustainable chemical processes. This study engineered shellac nanoparticle-lipase conjugates for biphasic biocatalysis. Taking advantage of the inherent amphiphilicity and pH-triggered interfacial behavior of the shellac, the conjugates exhibited dual functionality as intelligent Pickering emulsifiers and interfacial biocatalysts. The covalent conjugation strategy achieved a protein loading capacity of 107.97 ± 5.24 mg/g under optimized conditions while preserving interfacial responsiveness. Reversible emulsification/breaking transitions were precisely regulated at least 30 times through pH adjustment or alternating CO₂/N₂ treatments, enabling convenient catalyst recovery. When applied to the esterification of phytosterols with oleic acid, the conjugates exhibited a higher esterification rate (78.93 %, 1.5-fold enhancement compared with the free lipase), retained 85.0 % initial catalytic activity after six consecutive cycles. The responsive Pickering system combined exceptional recyclability and enhanced catalytic performance, providing an innovative pathway for the development of Pickering interfacial catalysis.
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