Guo Xuebai, Liu Cuixia, Feng Bin, Hao Yuanfeng
Department of Environmental Engineering, Henan Vocational College of Water Conservancy and Environment, Zhengzhou 450008, China.
School of Energy & Environment, Zhongyuan University of Technology, Zhengzhou 450007, China.
Membranes (Basel). 2022 Dec 28;13(1):38. doi: 10.3390/membranes13010038.
In northwest China, the limited amount of water resources are classified mostly as brackish water. Nanofiltration is a widely applied desalination technology used for brackish water treatment; however, membrane fouling restricts its application. Herein, we modified the membrane with triethanolamine (TEOA) and optimized the operating conditions (transmembrane pressure, temperature, and crossflow velocity) to control the nanofiltration membrane fouling by brackish water. Based on the physiochemical characteristics and desalination performance of the prepared membranes, the membrane modified with 2% TEOA (MPCM2) was identified as the optimal membrane, and 0.5 MPa, 25 °C, and 7 cm/s were identified as the optimal operating conditions through a series of nanofiltration experiments. Moreover, the membrane cleaning procedure for fouled MPCM2 was further determined, and a two-step cleaning procedure using ethylene diamine tetraacetic acid disodium followed by HCl with a permeance recovery rate of 98.77% was identified as the optimal cleaning procedure. Furthermore, the characterizations of the fouled and cleaned MPCM2 showed that the optimized cleaning procedure could recover the properties of MPCM2 to near virgin. This study is of great significance for the long-term stable operation of nanofiltration processes in brackish water treatment to ensure the supply of healthy water in the water-deficient areas of northwest China.
在中国西北部，有限的水资源大多属于微咸水。纳滤是一种广泛应用于微咸水处理的脱盐技术；然而，膜污染限制了其应用。在此，我们用三乙醇胺（TEOA）对膜进行改性，并优化操作条件（跨膜压力、温度和错流速度），以控制微咸水对纳滤膜的污染。基于所制备膜的理化特性和脱盐性能，经鉴定，用2% TEOA改性的膜（MPCM2）为最佳膜，通过一系列纳滤实验确定0.5 MPa、25℃和7 cm/s为最佳操作条件。此外，进一步确定了被污染的MPCM2的膜清洗程序，经鉴定，采用乙二胺四乙酸二钠 followed by HCl的两步清洗程序为最佳清洗程序，其渗透通量恢复率为98.77%。此外，对被污染和清洗后的MPCM2的表征表明，优化后的清洗程序可使MPCM2的性能恢复到接近初始状态。本研究对于微咸水处理中纳滤过程的长期稳定运行具有重要意义，以确保中国西北部缺水地区的健康用水供应。
