Modification of antibacterial and self-cleaning composite membrane using thermo-responsive hydrogel for fish ball industrial wastewater treatment

Membrane technology is commonly used to treat wastewater in the food industry. However, membrane fouling remains a major problem. This research aims to study the development of composite membranes with antibacterial properties and self-cleaning ability to solve the membrane fouling problem for fish ball industrial wastewater treatment. Polyethersulfone (PES) membrane was modified with poly(N-isopropyl acrylamide) (PNIPAM), sodium acrylate (SA), and [2-(methacryloyloxy)ethyl]trimethylammonium chloride (DMC), followed by adsorbing silver nanoparticles (AgNPs) onto the membrane surface. The results demonstrate that PNIPAM-SA and PNIPAM-DMC hydrogels at 100-0, 90-10, and 80-20 concentration ratios exhibit thermo-responsive properties. This thermo-responsive effect facilitates the self-cleaning of the membrane at 40 °C (higher than LCST). PES/PNIPAM-SA (80-20) membrane modified with AgNPs exhibited the highest antibacterial properties. For BSA filtration, it was found that the PES/PNIPAM-SA/Ag membrane had a flux that was twice as high as that of the PES/PNIPAM-DMC/Ag membrane. For the filtration of fish ball industrial wastewater, the PES/PNIPAM-SA/Ag membrane is capable of reducing COD, BOD, TKN, and TSS values by 96.64%, 98.13%, 74.68%, and 70.48% respectively. The wastewater quality of permeate passed the standard requirements. Membranes with self-cleaning and antibacterial properties are good candidates to develop for use in further wastewater treatment.