塑料清洗废水污染PVDF微滤膜的化学清洗研究

Chemical cleaning of PVDF microfiltration membrane polluted by plastic cleaning wastewater

以自制的PVDF中空纤维膜过滤塑料清洗废水进行污染实验,并对废水处理过程中被污染的PVDF膜的化学清洗进行了研究。采用了3种不同的化学清洗液进行单独清洗,分别为1%的NaOH、0.3%的NaClO、0.3%的SDS,结果表明单独的NaOH和NaClO清洗效果不佳,通量恢复率分别为45.18%和54.84%,用SDS清洗效果最好,通量可恢复至100%以上。对不同清洗方式的清洗效率进行了分析,结果表明同时使用NaOH和NaClO的“复配清洗”相较于两种清洗剂单独清洗的清洗效率较高,FRR值为72.63%。先用NaOH(或NaClO),后用柠檬酸的“先碱后酸”分段清洗效果好于碱性“复配清洗”,FRR值分别为75.44%和91.13%。并对清洗后的膜表面进行扫描电镜(SEM)观察,直接观察不同清洗方式的清洗效率。建议针对有机污染及生物污染造成的膜污染,可以采取SDS进行化学清洗,或者采用“先碱后酸”分段清洗方式进行清洗。

A self-made PVDF hollow fiber membrane was used to filter plastic cleaning wastewater.The chemical cleaning of PVDF membrane fouled during the process of plastic cleaning wastewater treatment was investigated.Three different chemicals including 1% NaOH,0.3% NaClO and 0.3% of SDS were used for separate cleaning.Results showed that the cleaning ability of separate cleaning by NaOH or NaClO was poor,the flux recovery rate were 45.18% and 54.84%,respectively.SDS was the best cleaning agent and the cleaning efficiency was obtained above 100%.The cleaning efficiency of different cleaning methods was analyzed,and the results showed that the "compound cleaning" using NaOH and NaClO at the same time had a higher cleaning efficiency compared with the two cleaning agents alone,with a FRR value of 72.63%.The cleaning efficiency of two-step cleaning method with NaOH(or NaClO) followed by citric acid were better than the “compound cleaning”,the FRR values were 75.44% and 91.13%,respectively.Also,the scanning electron microscopy(SEM) photographs of cleaned membrane surfaces were taken to directly observe the cleaning efficiency of different methods.Chemical cleaning by SDS or "alkali first and acid second" two-step cleaning method is recommended for PVDF membrane fouled by organic pollution and biological pollution.