JOURNAL OF MEMBRANE SCIENCE
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2024
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IF 8.4
Zhiyuan Hu,Yawei Gao,Gangfu Song,Jue Wang,Xiao-mao Wang
For thickening the polyamide (PA) active layer, the weakened aqueous monomer, piperazine-2-carboxylic acid (PIP–COOH), was selected to explore a new way of fabricating the thick and negative nanofiltration (NF) membranes via classic interfacial polymerization (IP). The presence of electron-withdrawing carboxyl on the PIP-COOH greatly reduced the reactivity to totally reserve ample time and space, especially at the early stage of the IP and in the incipient polymeric structure, respectively, for PIP-COOH continuously diffusing forward to extend the reaction zone. Furthermore, the extra introduction of carboxyl, belonging to PIP-COOH, significantly increased the negative charge density of the resultant membranes. The optimal membrane exhibited the high rejection (∼92.4 %) of Na 2 SO 4 and the effective removal of perfluorinated compounds (PFCs) (>80.0 %) while maintaining moderate water permeance of 5.2 L m −2 h −1 bar −1 and excellent durability. It was validated repeatedly that the sufficient supply of aqueous PIP-COOH ensured the thickness of active layer increased at least two-fold, most up to ∼200 nm.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2022
·
IF 3.428
Yunfeng Lei,Xuezhong Zhang,Xiangyu Meng,Zhifei Wang
The removal of methylene blue (MB) with the magnetic separation in water treatment is of increasing attentions due to its high solubility and chemical stability, which poses a great challenge on the ecological environment and human health. Herein, with assistance of simplified modification strategies, multi-carboxyl functionalized Fe 3 O 4 @SiO 2 magnetic nanoparticles (mCMNPs) have been developed with a novel insight into the grafting densities effects on the adsorption process. The results of UV–Vis spectrometry obviously showed that the increased carboxyl content on the surface of CMNPs resulted in the significant improvement in the removal process of MB. Among different types of CMNPs, mCMNPs were chosen for the separation of MB owing to possessing the highest surface carboxyl densities 0.2363 mmol/g and exhibiting the highest removal efficiency of 96.18%. Several important factors including solution pH, initial MB concentration and sorption time were optimized to achieve the best removal efficiency. Desired adsorption capacity for MB (34.75 mg/g) was achieved using mCMNPs with the pH 10, sorption time of 100 min and initial MB concentration of 50 mg/L. The sorption isotherms and sorption kinetics can be well in agreement with the Langmuir model and pseudo-second-order kinetic model, respectively. Most importantly, the synthesized mCMNPs still exhibited high removal efficiency (63%) after 5 cycle numbers. As adsorbents, it is noted that the prepared mCMNPs possessed the excellent regeneration ability and recyclability and could be a promising adsorbent for the removal of MB in water treatment.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 8
·6415-6422
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IF 3.289
Maofang He,Chaozhan Wang,Yinmao Wei
In this study, a weak cation-exchange (WCX) membrane was prepared via a “post-polymerization modification” method, which involved the surface-initiated atom transfer radical polymerization of glycidyl methacrylate (GMA) and subsequent two-step derivation. By varying the graft time of poly-GMA, a series of WCX membranes with different densities of carboxyl groups were fabricated. For the membrane with a graft time of 12 h, a high adsorption capacity of 125.0 mg mL−1 was obtained by using lysozme (Lys) as a model protein, which is higher than that reported. The new parameters, the utilization percentage of carboxyl (UP) and the stoichiometric displacement parameter (Z) were introduced to theoretically investigate how the ligand density affects the adsorption behavior of Lys for the first time. The UP revealed an “increase first and then decrease” trend with the prolonging of graft time, which may result from the mutual effect of the flexibility of the polymer chain, the steric hindrance and the “adsorption-caused hindrance” effect. Remarkably, the Z value was found to increase with the prolonging of graft time, suggesting that more effective binding sites were interacting with a protein molecule when the density of carboxyl was increased. Finally, the WCX membranes were applied to purify Lys from egg white with a high recovery of 95.7%, which depends significantly on the adsorption capacity of the membranes.
研究领域:
生物工程
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材料科学
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蛋白质组学
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DOI
高影响因子
MATERIALS AND STRUCTURES
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2023
·Vol. 57
·期 1
·1-17
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IF 3.8
Chen Xingren,Liu Zuguang,Fu Xiyao,Xie Xiongmin,Wang Ting,Rong Zhijuan,Nong Youchao,Lu Zhenren
A series of polycarboxylate superplasticizers (PCEs) with varying carboxyl densities were synthesized at room temperature using the molecular design principle. The PCEs molecular structure was determined using 1 H NMR and MALDI-TOF. The paste fluidity, foam stability as well as other performance of PCEs obtained was also tested. The investigations reveal that the PCEs with high carboxyl density cause the extended main chain conformation due to the strong electrostatic repulsion, resulting in the increase of hydrodynamic radius (Rh), which is beneficial to increase the ‘accessible carboxyl’ in the main chain, and improves its adsorption capacity; In addition, the PCEs with high carboxyl density also have high hydrophilicity, which will form micro bubbles to better disperse cement particles, and improve the fluidity of cement pastes. This study is aimed to provide a comprehensive understand for the mechanism of maleic anhydride-modified TPEG-type PCEs from the viewpoint of molecular architecture and conformation, and improve the workable performance of concrete mixture with the PCEs.
研究领域:
材料科学
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高分子化学
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土木工程
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表面化学
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DOI
高影响因子
危险品化学品经营许可证（带存储）