An easily recoverable thermo-sensitive polyelectrolyte as draw agent for forward osmosis process  

作　　者：Yanni Wang Hairong Yu Rui Xie Kuangmin Zhao Xiaojie Ju Wei Wang Zhuang Liu Liangyin Chu 

机构地区：[1]School of Chemical Engineering, Sichuan University [2]State Key Laboratory of Polymer Materials Engineering, Sichuan University

出　　处：《Chinese Journal of Chemical Engineering》2016年第1期86-93,共8页中国化学工程学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(21276162);the Program for Yangtse River Scholars and Innovative Research Team in Universities(IRT1163)

摘　　要：As a potential solution to the crises of energy and resources, forward osmosis(FO) has been limited by the development of draw agents. An ideal draw agent should be able to generate high osmotic pressure and can be easily recovered. In this study, a thermo-sensitive polyelectrolyte of poly(N-isopropylacrylamide-co-acrylic acid)(PNA)is developed as an efficient draw agent, and two easy and simple methods are proposed to effectively recover the polyelectrolytes. After adjusting the pH value of polyelectrolyte solutions to around 6.0, the polyelectrolyte can generate relatively high osmotic pressure, and induce average water fluxes of 2.09 and 2.95 L·m^(-2)·h^(-1) during12 h FO processes when the polyelectrolyte concentrations are 0.20 and 0.38 g·ml^(-1) respectively. After acidifying and heating to 70 °C, the PNA-10 polyelectrolyte can aggregate together because of hydrophobic association and separate from water, so it can be easily recovered by either simple centrifugation or gravitational sedimentation. The recovery ratios of PNA-10 polyelectrolyte in both methods are as high as 89%, and the recovered polyelectrolytes can be reused with almost the same FO performance as fresh ones. The results in this study provide valuable guidance for designing efficient and easily recoverable draw agents for FO processes.As a potential solution to the crises of energy and resources, forward osmosis（FO） has been limited by the development of draw agents. An ideal draw agent should be able to generate high osmotic pressure and can be easily recovered. In this study, a thermo-sensitive polyelectrolyte of poly（N-isopropylacrylamide-co-acrylic acid）（PNA）is developed as an efficient draw agent, and two easy and simple methods are proposed to effectively recover the polyelectrolytes. After adjusting the pH value of polyelectrolyte solutions to around 6.0, the polyelectrolyte can generate relatively high osmotic pressure, and induce average water fluxes of 2.09 and 2.95 L·m^（-2）·h^（-1） during12 h FO processes when the polyelectrolyte concentrations are 0.20 and 0.38 g·ml^（-1） respectively. After acidifying and heating to 70 °C, the PNA-10 polyelectrolyte can aggregate together because of hydrophobic association and separate from water, so it can be easily recovered by either simple centrifugation or gravitational sedimentation. The recovery ratios of PNA-10 polyelectrolyte in both methods are as high as 89%, and the recovered polyelectrolytes can be reused with almost the same FO performance as fresh ones. The results in this study provide valuable guidance for designing efficient and easily recoverable draw agents for FO processes.

关 键 词：Forward osmosis Draw agent Thermo-sensitive polyelectrolyte Recovery method Poly（N-isopropylacrylamide-co-acrylic acid） 

分 类 号：TQ028.8[化学工程] TQ317