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以混凝-超滤组合工艺中长期受污染的PVDF超滤膜为研究对象,考察不同化学清洗剂对跨膜压差(TMP)恢复的影响。利用扫描电镜(SEM)等仪器分析膜污染的构成,还采用三维荧光光谱技术分析了化学清洗对膜出水水质的影响。结果表明:超滤膜表面是有机污染物和无机污染物同时存在并相互作用而成,有机污染物以色氨酸类芳香族物质为主,无机污染物有Ca2+、Si 2+、Mg2+、Al 3+等;化学清洗的首要任务是清洗膜丝上的有机污染物;使用柠檬酸、NaOH、HCl、NaClO和NaClO+HCl等化学清洗剂对膜进行了化学清洗,发现NaClO和NaClO+HCl两种方案清洗后膜丝的TMP恢复较明显,渗透率恢复比分别为162%和169%,其中HCl和NaClO对膜的清洗有协同作用;经过化学清洗后膜丝存在初滤水的现象,初滤水中的颗粒数和溶解性有机物均有升高。
The coagulation - ultrafiltration combination of long-term contaminated PVDF membrane as the object of study, investigated different chemical cleaning agent on the transmembrane pressure drop (TMP) recovery. The composition of membrane fouling was analyzed by scanning electron microscopy (SEM) and other factors. The effect of chemical cleaning on membrane effluent quality was also analyzed by three-dimensional fluorescence spectroscopy. The results showed that the surface of the ultrafiltration membrane was formed by the simultaneous presence of organic pollutants and inorganic pollutants, the organic pollutants were mainly tryptophan aromatic substances, and the inorganic pollutants were Ca2 +, Si2 +, Mg2 +, Al 3+, etc. The primary task of chemical cleaning is to clean organic contaminants on the membrane filaments. The chemical cleaning of the membrane is carried out using chemical cleaning agents such as citric acid, NaOH, HCl, NaClO and NaClO + HCl. It is found that NaClO and NaClO + HCl two The TMP recovery of the membrane after cleansing was obvious, and the permeability recovery ratios were 162% and 169%, respectively. Among them, HCl and NaClO had a synergistic effect on the membrane cleansing. After chemical cleansing, Drainage of water in the number of particles and dissolved organic matter have increased.