预润湿对Janus陶瓷膜制备及布气性能的影响

Effect of pre-wetting on preparation and gas distribution performance of Janus ceramic membrane

膜分散是制备微气泡的有效手段之一。在膜分散过程中,膜表面润湿性对气泡的分散过程起着关键作用。通过不对称化学修饰法调节膜的润湿性,在亲水改性前引入预润湿处理经疏水改性过的陶瓷膜,制备了具有不对称润湿性的Janus陶瓷膜。研究了不同预润湿剂对Janus陶瓷膜结构、表面性质及化学组成的影响,并研究其在CO_(2)-NaOH体系中的气体分散与传质性能。结果表明,经预润湿处理制备的Janus陶瓷膜的亲水侧的润湿效果和亲水层的均匀程度均受到预润湿剂的表面张力和水溶性的影响。预润湿剂表面张力的减小,有利于Janus陶瓷膜上均匀的亲水层的沉积以及膜表面亲水性的增强。与未润湿处理相比,经乙醇预润湿制备的Janus陶瓷膜分散制备得到的气泡平均尺寸最小且分布最窄,传质效果也最优。

Membrane dispersion is one of the effective methods to prepare microbubbles.In the process of membrane dispersion,the wettability of the membrane surface plays a crucial role in the bubble dispersion process.Herein,Janus ceramic membranes with asymmetric wettability were prepared through asymmetric chemical modification.A pre-wetting treatment was introduced on the hydrophobic modified ceramic membranes before hydrophilic modification.The effects of different pre-wetting agents on the structure,surface properties,and chemical composition of the Janus ceramic membranes,as well as their gas dispersion and mass transfer performance in a CO_(2)-NaOH system were investigated.The results showed that the wettability of the hydrophilic side and the uniformity of the hydrophilic layer of the Janus ceramic membranes prepared after pre-wetting treatment were influenced by the surface tension and water solubility of the pre-wetting agents.The decrease of the surface tension of the pre-wetting agent was conducive to the deposition of a uniform hydrophilic layer on the ceramic membranes,and the enhancement of the surface hydrophilicity of the membranes.Compared to the untreated membranes,the Janus ceramic membranes prepared by ethanol pre-wetting had the smaller average bubble size and narrower size distribution,and the more optimal mass transfer performance.