芳香聚酰胺复合反渗透膜耐氯性及评价方法研究

发布时间：2018-02-04 12:56

本文关键词： 复合反渗透膜耐氯性动态测试静态测试评价方法　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：芳香聚酰胺复合反渗透膜因具有脱盐率高、水通量大等优点被广泛应用于水处理领域。然而,芳香聚酰胺复合反渗透膜较差的耐氯性受到人们长期地关注。目前,对芳香聚酰胺复合反渗透膜的氯化降解机理尚无定论,其耐氯性标准评价方法仍为空白。所以,对芳香聚酰胺复合反渗透膜进行耐氯性及评价方法的研究具有重要意义。本文分别采用动态测试方法和静态测试方法对芳香聚酰胺复合反渗透膜耐氯性进行了研究。利用反渗透膜测试设备对复合反渗透膜氯化前后的膜性能进行了测试。采用扫描电子显微镜(SEM),傅里叶变换红外光谱(ATR-FTIR),X-射线光电子能谱(XPS),表面水接触角测试仪(WCA)等对测试方法对膜表面形貌、化学结构和湿润性进行了表征分析。结合静态测试结果对芳香聚酰胺复合反渗透膜耐氯性评价方法进行了研究。结果表明:采用动态测试方法进行氯化时,随着氯化时间的增加,膜通量逐渐降低,膜截留率基本保持不变;采用静态测试方法进行氯化时,当活性氯浓度小于1000ppm时,膜性能随着活性氯浓度增大逐渐衰减,当活性氯浓度大于1000 ppm时,膜性能迅速衰减。造成膜性能衰减的原因有四个方面,包括膜表面聚酰胺层发生氯化降解,膜表面"峰谷"结构被压实或变得平缓,膜表面湿润性降低以及膜表面被污染物堵塞。由静态测试结果分析得到了芳香聚酰胺反渗透复合膜通量衰减方程y=a×xb(1x1000),该方程为芳香聚酰胺复合反渗透膜评价方法提供了依据,即根据膜通量衰减方程可以计算出特定活性氯浓度,氯化特定时间时膜的通量衰减量,再结合实际产水需求决定是否需要更换反渗透膜。本研究为芳香聚酰胺复合反渗透膜耐氯性的机理研究提供了基础数据,对其耐氯性评价方法的建立具有一定的指导意义。
[Abstract]:Aromatic polyamide composite reverse osmosis membrane is widely used in the field of water treatment because of its high desalination rate and large water flux. The chlorination degradation mechanism of aromatic polyamide composite reverse osmosis membrane has not been decided at present. People have long paid attention to the poor chlorine resistance of aromatic polyamide composite reverse osmosis membrane. The standard evaluation method of chlorine resistance is still blank. It is of great significance to study the chlorine resistance and evaluation methods of aromatic polyamide composite reverse osmosis membrane. In this paper, the chlorine resistance of aromatic polyamide composite reverse osmosis membrane is studied by dynamic test method and static test method, respectively. The properties of composite reverse osmosis membrane before and after chlorination were tested by reverse osmosis membrane test equipment. SEM). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), surface water contact angle tester (WCA), etc. The chemical structure and wettability were characterized and analyzed. The evaluation method of chlorine resistance of aromatic polyamide composite reverse osmosis membrane was studied in combination with the static test results. The results showed that the dynamic test method was used for chlorination. With the increase of chlorination time, the membrane flux gradually decreased and the membrane retention rate remained unchanged. When the concentration of active chlorine is less than 1000ppm, the performance of the membrane decreases gradually with the increase of the concentration of active chlorine, and when the concentration of active chlorine is greater than 1000ppm. There are four reasons for the degradation of membrane performance, including chlorination of the polyamide layer on the surface of the film, compaction of the "peak and valley" structure on the surface of the film, or becoming gentle. The surface wettability of the membrane was decreased and the membrane surface was blocked by pollutants. The flux attenuation equation of aromatic polyamide reverse osmosis composite membrane was obtained by static test. The equation provides a basis for the evaluation method of aromatic polyamide composite reverse osmosis membrane. According to the flux attenuation equation of the membrane, the flux attenuation of the membrane can be calculated when the specific concentration of active chlorine and the specific time of chlorination can be calculated. Combined with the actual demand for water production to determine the need to replace reverse osmosis membrane. This study provides basic data for the study of chlorine resistance mechanism of aromatic polyamide composite reverse osmosis membrane. It has certain guiding significance for the establishment of evaluation method of chlorine resistance.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.893

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