Anionic and cationic barium alginate cellulose composite membrane for oil/water separation

This study demonstrates the fabrication of barium alginate cellulose composite membranes to separate the oil from water. The sodium alginate solution was sprayed on the cellulose membrane surface, and immersed in a barium chloride solution. The soaking time varied from 30 to 120 minutes. Results show that the barium alginate gel filled the micropores, thus reducing the surface porosity of the membrane. The extended soaking time caused the pores to reopen as a result of the crosslinking shrinkage. The barium alginate gel also reduced the ridge-like structure of the cellulose membrane surface, resulting in a reduction in surface roughness. The water contact angle (WCA) of the composition membranes was 0°, while their oil contact angles (OCAs) ranged between 50 and 57°, indicating that they were superhydrophilic and oleophilic in air. The synergistic effect of anionic and cationic properties increased the superhydrophilicity and form a hydration layer on the composite membrane surface, improving the anti-oil adhesion. The composite membrane has an exceptional separation efficiency of over 97% and a water flux of more than 330 L m-2 h-1. The low cost and excellent performance of the barium alginate cellulose composite membrane point to a high potential for oily wastewater treatment applications.