Novel chitosan/poly(vinyl) alcohol thin adsorptive membranes modified with amino functionalized multi-walled carbon nanotubes for Cu(II) removal from water: Preparation, characterization, adsorption kinetics and thermodynamics

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• 作者：E. Salehi^a ; S.S. Madaeni^a ; ^{smadaeni@yahoo.com} ; L. Rajabi^b ; V. Vatanpour^a ; A.A. Derakhshan^b ; S. Zinadini^a ; Sh. Ghorabi^b ; H. Ahmadi Monfared^a
• 关键词：Adsorptive membrane ; Thermodynamic ; Chitosan ; Polyvinyl alcohol ; Functionalized MWCNTs
• 刊名：Separation and Purification Technology
• 出版年：2012
• 期刊代码：78_13835866
• 类别：ce
• 出版时间：22 March, 2012
• 卷：89
• 期：Complete
• 页码：309-319
• 文件大小：2068 K

摘要

In the current study, amino functionalized multi-walled carbon nanotubes (MWCNT-NH₂) were synthesized from raw MWCNTs and utilized to prepare novel chitosan/PVA thin adsorptive membranes for copper ion removal from water. Various weights of the CNTs were embedded in the membranes to obtain the optimum MWCNTs content. Finger-like nanochannels appeared in the compact structure of the CS/PVA membrane by addition of 0.5 wt.%of the MWCNTs; however, fibril-shape and dense structures were generated at higher percent weights i.e. 1 and 2 wt.%, respectively. Adsorption capacity of the membrane containing 2 wt.%MWCNTs (20.1 mg/g at 40 掳C) was almost twice as large as that of the plain membrane (11.1 mg/g); however, capacity enlargement was not significant (<3 mg/g), when MWCNTs content raised from 1 to 2 wt.%. This indicates that the optimum CNT loading is 1 wt.%. Freundlich isotherm could, thus, superiorly describe the adsorption equilibria. Thermodynamic studies revealed spontaneous (螖G掳 < 0) and endothermic (螖H掳 > 0) adsorption together with entropy generation (螖S掳 > 0) at the solid/liquid interface. Additionally, kinetic studies showed that membranes with higher MWCNTs content could support faster adsorption rate. No significant adsorption capacity loss (鈭?%) was observed for the membrane containing MWCNT-NH₂ in comparison to the capacity loss of the plain membrane (鈭?0%) after four successive adsorption/regeneration cycles. The results suggested that the novel CS/PVA/MWCNT-NH₂ composite membranes can be effectively applied for the adsorptive removal of copper ions from aqueous solutions.