Adsorption of neutral and negatively charged low-molecular-weight carbonyls in reverse osmosis permeates by ion-exchange resins

Q1 Environmental Science
Han-Ying Cai , Wen-Long Wang , Wan-Yue Ouyang , Qian-Yuan Wu , Li Zhang , Hong-Ying Hu
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引用次数: 2

Abstract

Reverse osmosis (RO) has been increasing widely used in water and wastewater treatment to provide high-quality water, such as in industrial pure water production and municipal (non)potable water reuse. However, some low-molecular-weight (LMW) compounds, such as LMW carbonyls, penetrate through RO membranes and are present in the RO permeate, resulting in potential risk to human health or industrial production. Ion-exchange (IX) resins are widely used to help eliminate residual LWM organic compounds from RO permeates, but their elimination performance for carbonyls is not well understood. In this study, seven commercially available resins were employed to explore the adsorption performance for the elimination of representative carbonyls in RO permeate. In general, the adsorption performance of selected resins with regular polymer composition, pore structure and functional group was poor for LMW neutral carbonyl compounds, but efficient for carboxylic acids (number of carbon atoms is less than 4). Among target carboxylic acids, the gel-N+(CH3)3 resin exhibited rapid adsorption kinetics, performing better in the removal of LMW carboxylic acids with shorter alkyl chains and more carboxyl groups. In particular, binary carboxylic acids were adsorbed 3–5 times faster on resins compared with their monoacid counterparts. Charge density was the dominant factor affecting the adsorption performance of carbonyl compounds, followed by hydrophobicity, molecular chain length, and the presence of H attached to the carbonyl C. This study implies that neutral carbonyls cannot be efficiently eliminated by IX resin, and green oxidation processes, such as vacuum UV oxidation, are suggested for the conversion of such compounds to readily removable negatively charged carboxylic acids.

Abstract Image

离子交换树脂在反渗透中对中性和带负电的低分子量羰基的吸附
反渗透技术(RO)越来越广泛地应用于水和废水处理,以提供高质量的水,如工业纯水生产和城市(非)饮用水回用。然而,一些低分子量(LMW)化合物,如低分子量羰基,可穿透反渗透膜并存在于反渗透渗透物中,对人类健康或工业生产造成潜在风险。离子交换(IX)树脂被广泛用于去除RO渗透物中残留的LWM有机化合物,但它们对羰基的去除性能尚不清楚。本研究采用7种市售树脂对反渗透渗透液中代表性羰基的吸附性能进行了研究。总的来说,聚合物组成、孔结构和官能团规则的树脂对LMW中性羰基化合物的吸附性能较差,而对羧酸(碳原子数小于4)的吸附性能较好。在目标羧酸中,凝胶- n +(CH3)3树脂表现出快速的吸附动力学,对烷基链较短、羧基较多的LMW羧酸具有较好的去除效果。特别是,二元羧酸在树脂上的吸附速度比单酸快3-5倍。电荷密度是影响羰基化合物吸附性能的主要因素,其次是疏水性、分子链长和羰基c上是否存在H。该研究表明,中性羰基不能被IX树脂有效地去除,因此建议采用真空紫外氧化等绿色氧化工艺将这些化合物转化为易于去除的带负电荷的羧酸。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Water Cycle
Water Cycle Engineering-Engineering (miscellaneous)
CiteScore
9.20
自引率
0.00%
发文量
20
审稿时长
45 days
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