Sr掺杂SiO2膜的制备及其脱盐性能研究

The Fabrication and Desalination Performance of Strontium-Doped SiO2 Membranes

以正硅酸四乙酯(TEOS)为硅烷前驱体,以氯化锶(SrCl2)为Sr源,采用溶胶-凝胶法制备了Sr掺杂的SiO2膜.通过系列表征结果证实:在水解缩合反应过程中Sr被掺杂到SiO2骨架中,形成了水热稳定的Si—O—Sr键,明显地改变了膜的表面形貌、微观结构和亲水性,从而提高了膜的脱盐性能和稳定性.在优化合成条件(n(Sr)∶n(TEOS)=0.075∶1.000)下所制备的Sr/SiO2膜的脱盐性能最佳.在60℃条件下,当以质量分数为3.5%的NaCl溶液为进料液时,该膜的水通量高达20.7 kg·m-2·h-1,盐截留率接近100.0%.此外,在35~60℃连续性温度循环测试中,该膜显示出了优异的水热稳定性.

Strontium-doped silica membranes are successfully prepared by the sol-gel method with tetraethyl orthosilicate(TEOS)as silane precursor and SrCl2 as strontium source.It is confirmed by various characterization results that Sr is doped into the SiO2 framework during the hydrolysis condensation reactions,forming hydrothermally stable Si—O—Sr bond.It can significantly change membrane surface morphology,microstructure properties and hydrophilicity thus to enhance the desalination performance.Under optimized synthesis conditions(n(Sr)∶n(TEOS)=0.075∶1.000),the desalination performance of the Sr/SiO2 membrane prepared is the best.At 60℃,when the w(NaCl)=3.5%solution is the feed solution,the water flux of the membrane is as high as 20.7 kg·m-2·h-1 and the salt rejection rate is nearly 100.0%.In addition,the membrane demonstrated excellent hydrothermal stability in continuous test at 35~60℃.