海藻酸钠修饰磁性纳米粒子驱动液及其正渗透分离性能

Sodium alginate modified magnetic nanoparticle draw solution and its forward osmosis performance

通过微乳液共混沉淀法制备了海藻酸钠(SA)修饰的Fe3O4磁性纳米粒子Fe3O4 SA,该粒子具有良好的分散性和磁响应性.采用红外、透射电镜、磁滞回线和热失重等对磁性纳米粒子的结构和性能进行表征,同时对该磁性纳米粒子与去离子水的混合液作为驱动液时的正渗透(FO)分离性能进行了测试.结果表明,SA成功包覆在Fe3O4粒子表面,粒子的粒径约为20 nm,80 g/L的Fe3O4 SA磁性纳米粒子与去离子水的混合液渗透压达到1270 mOSM/L,以此混合液作为FO过程的驱动液时,渗透通量可以达到2.04 L/(m^2·h),并且该驱动液具有较低的反向溶质通量,当驱动液质量浓度为80 g/L时,反向溶质通量约为0.04 g/(m^2·h),大大低于NaCl和SA的反向溶质通量,这说明该驱动液具有较好的FO分离性能.

Fe3O4 SA magnetic nanoparticles with good dispersibility and magnetic response were prepared by emulsification blending precipitation method.The structure and performance of the magnetic nanoparticles were characterized by the infrared spectroscopy,transmission electron microscopy,hysteresis loops and thermogravimetric analysis,and at the same time the forward osmosis performance of FO using Fe3O4 SA magnetic nanoparticles as the draw solution was also investigated.The results showed that SA was coated successfully on the surface of Fe3O4 particles and the nanoparticle size is about 20 nm.The osmotic pressure of 80 g/L Fe3O4 SA aqueous solution reached 1270 mOSM/L,when this Fe3O4 SA aqueous solution was used as the draw solution for the FO process,the permeation flux could reach 2.04 L/(m^2·h).Fe3O4 SA aqueous solution had low reverse solute flux,its value was 0.04 g/(m^2·h)which was much lower than those of NaCl and SA when the concentrations were 80 g/L.These phenomena suggested that this magnetic nanoparticle had good forward osmosis separation performance.