超细TiO_2粒子的超滤分离及回用特性

Separation of ultrafine titanium dioxide particle from slurry by ultrafiltration process and its reuse

针对TiO2超细粒子的超滤分离特性进行了试验研究,探讨了操作压力、膜面流速、TiO2投量、pH、电解质等参数条件对膜通量的影响规律及作用机理,证实了浓差极化及滤饼层阻力是影响通量变化的主导因素,在此基础上确定了适宜的超滤工艺条件及膜清洗方式。以甲基橙为降解基质分别测试了经混凝与超滤分离后的TiO2光催化活性,结果表明,超滤不仅可实现TiO2粒子与水的彻底分离,且分离后TiO2催化活性与初次使用相当。研究表明超滤用于悬浮光催化体系的固液分离及催化剂再用是可行的。

This study focuses on the separation of ultrafine titanium dioxide ptotocatalyst from its aqueous suspensions and its reuse by crossflow ultrafiltration process. The effects of process parameters on the permeation flux such as transmembrane pressure, crossflow velocity, TiO_2 concentration in suspension, pH and electrolyte were investigated. It has been shown permeate flux is strongly affected by concentration polarization and filter cake resistance. Based on the experiment, appropriate separation conditions and membrane clearing means were put forward. In comparison with a coagulation process, a completely separation of titanium dioxide from water could be carried out by ultratfiltration. Furthermore, it was discovered that photocatalytic activity of the separated titanium dioxide is almost the same as a new one and it could be satisfactorily reused.