Superhydrophilic micro/nano hierarchical functionalized-CuO/PVDF nanocomposite membranes with ultra-low fouling/biofouling performance for acetate wastewater treatment: MBR application

Abstract

In membrane bioreactor (MBR) application, there are considerably influencing factors on membrane performance over time making serious problems, including reduced permeation flux and rejection percentage as well as formed thick fouling/biofouling layer. This study provided a new preparation strategy to fabricate extraordinary superhydrophilic CuO/PVDF nanocomposite membranes with micro/nano hierarchical structure, using a wet micro-pattern casting knife with simultaneous bombardment of hydrophilic CuO nanoparticles/non-solvent solution via cold spray coating (s-NIPs method). When compared to the neat membrane, the main characteristics of the superhydrophilic membrane enhanced such as surface area (70%) and pure water flux (PWF) (400%). Protein rejection (PR) and chemical oxygen demand (COD) removal were also obtained as about 96.7% and 97.8% at constant mixed liquor suspended solids (MLSS = 6000 mg/l) in a submerged aerobic MBR, fed by the synthesized sodium acetate wastewater (compared to the neat case: 78% and 91%), respectively. Furthermore, its excellent antifouling/biofouling properties were proved via significantly less formation of biofilm and adherence of extracellular polymeric substances (EPSs) and soluble microbial products (SMPs) on the membrane surface. Low variation of sludge flux and COD removal by increasing MLSS from 6000 (348 LMH and 96.7%) to 12000 mg/L (200 LMH and 94.2%) proved the significant impact of the preparation method on the membrane performance. Stability of the F–CuO coated layer caused superhydrophilicity and antibacterial properties to be maintained under long-period. The obtained results demonstrated potential of the fast, facile, simple, and one-step preparation method without compromising the membrane separation ability, while simultaneously providing superhydrophilicity, antibacterial activity, and ultra-low fouling/biofouling formation.