平板陶瓷载体上SiO_(2)-ZrO_(2)膜的制备及其纳滤性能研究

Nanofiltration performance of SiO_(2)-ZrO_(2) membrane prepared on flat ceramic support

采用颗粒溶胶路线合成含有不同粒径的SiO_(2)-ZrO_(2)溶胶,将其涂覆于中空平板陶瓷微滤膜上制备SiO_(2)-ZrO_(2)纳滤膜并用于双氯芬酸钠的分离.在用粒径为42 nm的SiO_(2)-ZrO_(2)溶胶对载体修饰的过程中,得出最佳溶胶质量分数和涂覆次数分别为0.5%和4次.继而采用17 nm的小粒径SiO_(2)-ZrO_(2)溶胶进一步涂覆,形成了更小孔径的膜,其截留分子量为310.在25℃和0.6 MPa的操作压力下对50 mg/L双氯芬酸钠水溶液进行纳滤测试,其通量为2.40 L/(m^(2)·h),截留率为95.1%.当料液温度为70℃时,膜的渗透通量达到8.25 L/(m^(2)·h),对双氯芬酸钠的截留率仍然保持在92.0%以上.

SiO_(2)-ZrO_(2) sol with different sizes were synthesized by colloidal sol route to prepare nanofiltration membranes on hollow flat ceramic for the separation of diclofenac sodium.The concentration and coating times of SiO_(2)-ZrO_(2) sol with particle size of 42 nm were optimized as 0.5%for 4 times on supports.Then the pore size of membrane could be further reduced by SiO_(2)-ZrO_(2) sol with particle size of 17 nm,resulting in a molecular cutoff weight of 310 as nanofiltration membrane.At 25℃and 0.6 MPa,the membrane flux was 2.40 L/(m^(2)·h)and the rejection was 95.1%in nanofiltrated 50 mg/L diclofenac sodium solutions.When the temperature was increased to 70℃,the flux reached to 8.25 L/(m^(2)·h),and the rejection of diclofenac sodium remained above 92.0%.