Bubble Drainage Assisted Fabrication of Polyamide Membranes with Crater-like Structures for Efficient Desalination
Xu Dong, Yu Zheng, Hao Deng, Xiao Pang, Tao Wu, Shiyi Zhu, Runnan Zhang, Zhongyi Jiang
Abstract
Bubble drainage (BD) occurs in various natural phenomena and industrial activities, in which bubbles rise toward the water surface and create a progressively thinned two-sided liquid film, called a lamella. Surfactant, as an important regulator in the BD process, not only assembles on both sides of the lamellae, generating a configuration of lamellae sandwiched by monolayers of surfactants (lamellae/MS), but also induces interfacial deformation by lowering interfacial tension. Herein, we developed a strategy of BD assisted interfacial polymerization for the fabrication of polyamide (PA) membranes. The regulated interfacial deformation at the water–oil interface produced a membrane with crater-like structures, which greatly increased the surface area of the PA membrane. Moreover, the lamellae/MS configuration served as a reservoir to spontaneously enrich amine monomers and thus modulate the diffusion-reaction kinetics. The resulting PA membranes exhibited superior separation performance with a water permeance of 44.7 L m –2 h –1 bar –1 and a Na 2 SO 4 rejection of 99.2%.