CHEMICAL ENGINEERING SCIENCE
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2022
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IF 4.889
Chenyang Zhao,Hongwei Zhu,Yujia Liu,Junjie Feng,Xiang Feng,Wei Xu,Zhe Yang,Bing Sun
The direct epoxidation of propylene has been a hot topic in the academic field for years. Researchers have spent extensive effort on the development of catalyst, however, only limited attention on the effect of reaction conditions, especially pressure. In this paper, we found for the first time that elevated pressure should favor the forward epoxidation reaction, it actually led to a drop of reaction rate in this system. We proposed explanation by considering the difficulty of gas molecules diffusing into and out of the micropores on the TS-1 zeolite surface. Higher pressure would inhibit the escaping of the gas molecules from the micropores and lead to carbon deposition inside the channel. To validate this hypothesis, we designed and compared catalysts with micropores blocked (BTS-1) and unblocked (TS-1) and found that the BTS-1 showed higher resistance to pressure change and significantly longer life time than the TS-1.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2019
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IF 7.015
Sushuang Li,Jianquan Luo,Xiaofeng Hang,Shiguang Zhao,Yinhua Wan
Polycyclic aromatic hydrocarbons (PAHs), as a group of micropollutants with high toxicity, are commonly detected in the environment and difficult to remove. In this work, five commercial polyamide (PA) nanofiltration (NF) membranes were used to treat three PAHs in the synthetic solution or coking wastewater and their removal mechanisms were discussed. By comparing water permeability and PAHs rejections of the NF membranes before and after PAHs adsorption, we found that the PAHs adsorption into the membrane was the dominant rejection mechanism at the initial filtration stage. Due to the limited adsorption capacity and increasing diffusion of PAHs in the membrane, the PAHs rejections would drop rapidly and then reach steady. Size exclusion mechanism was also important to PAHs removal by NF, especially for PAHs with weaker polarity and higher molecular weight. Although the polysulfone intermediate layer could adsorb substantial PAHs resulting in an increase of filtration resistance, the pore blocking and narrowing effects on the PA separation layer were still the main reasons for the permeability loss of NF membranes. However, the glucose rejection did not change obviously after the PAHs adsorption in the membrane. Through analyzing porosity and pore size distribution of the NF membranes before and after PAHs adsorption, we found that for the NF membrane with small pore size and narrow pore size distribution (e.g. NF270), PAHs adsorption produced indiscriminate pore blocking effect, and thus the average pore size and its distribution as well as glucose rejection did not change obviously after fouling formation; while for the NF membrane with large pore size and wide pore size distribution (e.g. NF10), PAHs adsorption occurred more seriously in the larger pores leading to a pore narrowing effect, but the reduced pore size was still too large to affect glucose rejections. The outcomes of this work suggested that the PAHs adsorption in both separation and intermediate layers of NF membranes should be avoided, and the NF membrane with narrow pore size distribution was preferred for PAHs removal.
研究领域:
环境工程
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水处理
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膜技术
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污染物去除
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
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IF 8.6
Yong Xiang,Chang-Yuan Cheng,Meng-Hao Liu,Wen-Cai Bai,Zhou-Xuan Zang,Li Xu,Yi Yu,Guo-Ji Liu
The design of an efficient adsorbent for Au(III) has remained a challenging research focus, as the adsorbent needs to overcome competition from other ions while simultaneously addressing pore blockage caused by the reduction of Au(III) to elemental gold. In this study, we report the synthesis of a hierarchically porous metal–organic frameworks (MOFs) with ultra-large pores (300 nm) using the “MOF in MOF” method. This material facilitates enhanced adsorption kinetics by increasing the rate of gold ion adsorption and effectively prevents pore blockage resulting from Au(III) reduction, enabling access to the majority of adsorption sites. Batch experiments were conducted, and various complex water mixtures, including freshwater, simulated electronic waste solution, and gold ore leachate, were tested to demonstrate the rapid extraction of trace amounts of gold by the developed adsorbent. Remarkably, without additional functionalization, the adsorbent solely based on its pore advantage achieved a gold adsorption capacity of 1184 mg/g and reached 80 % adsorption within just 5 min (C0 = 100 mg/L, V/m = 2 L/g). Furthermore, the gold recovered from the leachate of gold ore exhibited a purity of 23.8 K (99.2 % purity).
研究领域:
材料科学
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环境工程
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2024
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IF 8
Yahui Li,Yanan Dong,Shangqing Chen,Yingqiu Wu,Junfeng Wang,Yi Nie
Nanofiltration (NF) has been proven to be with great potential for the separation of morpholines with molecular weight less than 200 Da in refining reverse osmosis concentrate (ROC), but its application is significantly restricted by the membrane fouling , which can reduce the rejection and service time. To enable the long-term operation stability of nanofiltration, this work focuses on the fouling behavior of each substance in the hydrosaline organic solution on nanofiltration membrane, aiming to give insight into the fouling mechanism. To this end, in this work, the effects of salts (i.e NaCl and Na 2 SO 4 ), organic substances (including N-(2-hydroxypropyl)morpholine(NMH) and 4-morpholineacetate(MHA)) and representative divalent ions (Ca 2+ and Mg 2+ ) on the performance and physicochemical properties of DK membrane were systematically investigated. The results show that both salts and organics can induce DK membrane swelling, leading to an increase of the mean effective pore size. After the filtration of Na 2 SO 4 –NaCl–H 2 O, the mean pore size increased by 0.002 nm, resulting in the decrease of the removal ratio of NMH and MHA for 3.82% and 13.10%, respectively. With static adsorption of NMH and MHA, the mean pore size of DK membrane increased by 0.005 and 0.003 nm. The swelling slowed the entrance of more organic molecules into membrane pores. Among them, MHA led to the terrible irreversible pore blocking. As the concentration of Ca 2+ increased, gypsum scaling was formed on the membrane surface. During this process, NMH and MHA played different roles, i.e. NMH accelerated the CaSO 4 crystallization while MHA inhibited. As a conclusion, the fouling behavior of substances in the high saline organic wastewater on DK membrane were systematically revealed with the fouling mechanisms proposed, which could provide an insightful guidance for membrane fouling control and cleaning in the treatment of high salinity and organic wastewater.
研究领域:
环境工程
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水处理
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膜技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）