ZCS-TiO2 Modified Bacterial Cellulose Multifunctional Membranes for Highly Effective and Antibacterial Oil-Water Separation

Oil-water separation has given superhydrophilic/underwater superoleophobic (SUS) membrane technology a lot of attention. However, manufacturing multifunctional membranes to meet the complexities of oily wastewater treatment remains a huge challenge. In this work, a multifunctional SUS membrane based on bacterial cellulose (BC) was designed for oil-water separation. ZnCo2S4 (ZCS) was coupled to the surface of TiO2 nanoparticles to form ZCS-TiO2 by the simple hydrothermal synthesis method, and then BC nanofibers were mixed with ZCS-TiO2 to prepare a membrane. Oil/water (o/w) separation is accomplished by the composite membrane at a low drive pressure (0.2-0.3 bar). Its flux is 8232.81 +/- 212 L.m(-2) h(-1), and the separation efficiency can exceed 99.9%. In addition, the composite membrane also has good photocatalytic performance, the degradation rate of 20-BC/ ZCS-TiO2 for dye within 2 h was 80%. The composite membrane's antibacterial efficacy against gram-positive and gram-negative pathogens was also investigated at the same time, the BC/ZCS-TiO2 membrane with the lowest content of ZCS-TiO2 reduced the bacterial viability of Staphylococcus aureus and Escherichia coli by 40.32% and 30.64%, respectively. With the increase of ZCS-TiO2 content, the bacteriostatic activity also increased; 20-BC/ZCS-TiO2 completely eradicated both strains (no viable colonies). This work may shed some light on the manufacture of a new generation of multifunctional membranes for wastewater treatment, especially water contaminated with oily wastewater, dyes, and microorganisms.