超滤膜深度处理煤制气废水的化学清洗研究

Study on Chemical Cleaning of UF Membrane Filtration by Coal Gasification Wastewater

用实验室自制超滤膜系统深度处理煤制气废水。采用扫描电镜和能谱分析比较了质量为一定浓度均为0.5%的NaClO溶液(有效氯为5%)、NaOH溶液,HCl溶液对污染膜丝内表面滤饼层的静态浸泡效果。为进一步确定不同清洗剂的化学清洗效果,选用质量浓度为0.25%的NaOH溶液和0.25%的NaClO溶液对污染膜组件进行了手动化学清洗并通过过滤纯水确定清洗效率。结果显示,NaClO溶液和NaOH溶液对滤饼层分别具有溶解和剥离作用,从而对滤饼层起到了去除作用;能谱分析显示采用这两种清洗剂后的膜丝内表面元素组成与原膜较为接近,SEM分析则显示二者在去除滤饼层的同时对膜表面性状均有一定程度的改变;而经HCl溶液浸泡后的膜丝滤饼层未见去除,能谱分析显示此时膜丝内表面的元素组成与原膜有显著差异。手动化学清洗结果进一步显示,0.25%的NaClO溶液对膜组件的清洗效率可达到97%。

Laboratory self - made ultrafihration membrane system was used to deal with coal gasification wastewater. Scanning electron microscope （SEM） and energy spectrum were used to compare the three chemical agents including NaC10 solution （active chlorine is 5% ）, NaOH solution and HC1 solution, whose mass concentration were O. 5%. In order to identify the effect of different chemical agents, NaCIO solutioo and NaOH solution with the mass concentration of O. 25% were used to clean membrane modules, at the same time, the cleaning efficiency was defined. The results indicated that the cake layer was dissolved in the NaC10 solution, and stripped in NaOH solution. The analysis of energy spectrum indicated that the elemental composition inner the membrane was closed with that of the virgin membrane, and the analysis of SEM revealed that surface properties of the membrane was changed to some extent; but the cake layer inner membrane immersed in the HC1 solution wasn＇t removed and the elemental composition inner the membrane was marked different with that of virgin membrane by energy spectrum. The results of manual chemical cleaning fur ther revealed that the cleaning efficiency of NaC10 solution with mass concentration of 0. 25% was reached 97%.