Table1_In-situ ionized construction of PVDF/sodium polyacrylate-grafted-PVDF blend ultrafiltration membrane with stable anti-oil-fouling ability for efficient oil-in-water emulsion separation.DOCX

Traditional polymeric membranes usually suffer from serious oil fouling and quick decline of water flux when separating oil-in-water emulsions. In this work, we report the fabrication of the sodium polyacrylate (PAAS) blended polyvinylidene fluoride (PVDF) ultrafiltration membrane which behaves hydrophilicity, underwater low-oil-adhesive superoleophobicity and outstanding anti-oil-fouling ability even for viscous crude oil. The blend membrane was fabricated via a two-step method, including the nonsolvent-induced phase inversion of PVDF/polyacrylic acid-grafted-PVDF (PVDF/PAA-g-PVDF) blend membrane and the subsequent in-situ ionization of PAA into PAAS. The two-step method improves the affinity between the strong hydrophilic additive PAAS and the hydrophobic polymer matrix PVDF, thus endowing the blend membrane with long-term stable superwetting property for 1,100 days. The PVDF/PAAS-g-PVDF blend membrane can efficiently separate multiple emulsifier-stabilized oil-in-water emulsions with ultrahigh separation efficiency of 99.97% (the residual oil content in the filtrate is lower than 3 ppm after one-step separation) and high water flux of 350 L m-2 h-1 bar-1. The blend membrane also shows good cycling performance, and can be easily cleaned by water washing during several separation cycles of the crude oil-in-water emulsion. This work inspires a feasible route of fabricating stable anti-oil-fouling membranes for separation of emulsified oily water.

传统聚合物膜在分离油包水乳液时，通常遭受严重的油污染以及水通量的迅速下降。本研究中，我们报道了一种钠型聚丙烯酸（PAAS）与聚偏氟乙烯（PVDF）复合的超滤膜的制备，该膜表现出亲水性、水下低油粘附的超疏油性以及卓越的抗油污染能力，即便是对于粘稠的原油也不例外。该复合膜通过两步法制备而成，包括PVDF/聚丙烯酸接枝-PVDF（PVDF/PAA-g-PVDF）混合膜的溶剂非引发相转化以及随后聚丙烯酸（PAA）原位离子化为PAAS。两步法提高了强亲水性添加剂PAAS与疏水性聚合物基质PVDF之间的亲和力，从而赋予了复合膜长期稳定的超润湿性能，长达1100天。PVDF/PAAS-g-PVDF复合膜能够高效地分离多种乳化剂稳定的油包水乳液，具有99.97%的超高分离效率（单步分离后滤液中的残留油含量低于3 ppm）和350 L·m-2·h-1·bar-1的高水通量。该复合膜还显示出良好的循环性能，在多次原油水乳液分离循环中，可以通过水洗轻松清洁。本研究为制备稳定的抗油污染膜以分离乳化油污水提供了一条可行的途径。