膜集成技术处理氯化法钛白后处理废水的研究

氯化法钛白无机包膜处理工序会产生大量中性废水,其中包含少量钛白粉和水溶性盐,现阶段企业多以外排为主。采用膜集成（陶瓷膜+反渗透膜+纳滤膜）技术对氯化法钛白后处理废水的处理进行研究。将氯化法钛白后处理废水用陶瓷膜过滤,分离回收二氧化钛;将陶瓷膜清液用反渗透膜浓缩,清水回收利用;将反渗透浓液用纳滤膜分离硫酸钠和氯化钠。结果表明：利用陶瓷膜处理氯化法钛白后处理废水,平均通量为650 L/（m ²·h）,浓液中钛白粉质量浓度达到90 g/L以上,清液中钛白粉质量浓度低于0.001 g/L;使用反渗透膜截留清液中的硫酸钠和氯化钠,硫酸钠和氯化钠的截留率为99.5%,浓水中的盐质量分数达到4%以上;浓水中的硫酸钠和氯化钠通过纳滤膜分离,纳滤膜对硫酸钠的截留率为97%,硫酸钠质量分数达到14%以上。

Study on membrane integration technology in treatment of wastewater from chlorinated titanium dioxide

A large number of neutral wastewater will be produced in the process of chlorinated titanium dioxide by inorganic coating treatment technology,which contains a small amount of titanium dioxide and water-soluble salts.At present,the titanium dioxide and water-soluble salts are discharged outside by most of the enterprises.The membrane integration（ceramic membrane+reverse osmosis membrane+nanofiltration membrane) treatment process was used to study the chlorination titanium dioxide post-treatment wastewater.TiO₂ was separated and recovered by ceramic membrane filtration;the clear liquid of ceramic membrane was concentrated by reverse osmosis membrane and the clean water was recycled;the concentrated liquid of reverse osmosis was separated by nanofiltration membrane to separate sodium sulfate and sodium chloride.The results showed that the average flux of ceramic membrane was 650 L/（m ²·h）,the mass concentration of titanium dioxide in the concentrate was 90 g/L,and mass concentration of titanium dioxide in permeate was less than 0.001 g/L.With the filtration of reverse osmosis membrane,retention rate of sodium sulfate and sodium chloride could reached above 99.5% and the mass fraction of salt in concentrated water was above 4%.Sodium sulfate and sodium chloride in concentrated water were separated by nanofiltration membrane.With the filtration of nanofiltration membrane,retention rate of sodium sulfate could reached 97%.Sodium sulfate concentration can reach more than 14%.