Nano CuAl2O4 spinel mineral as a novel antibacterial agent for PVDF membrane modification with minimized copper leachability

The employment of copper-containing antibacterial agents for membrane modification can constrain undesirable bacterial adhesion and growth in an effective and economical way. However, copper ion may be leached out and cause further toxicity after applying those materials for membrane processes. Therefore, in this study, nano CuAl2O4 spinel was synthesized as a novel copper-containing material which was expected to have good antibacterial activity and simultaneously stabilize copper ions by its intrinsic structure. The obtained nano spinel was applied for membrane modification via both doping and coating methods. Results show that the addition of nano CuAl2O4 spinel during doping process can change polyvinylidene fluoride (PVDF) membrane properties (crystallization, tensile strength, porosity, pore size distribution, permeate flux and bovine serum albumin (BSA) rejection) obviously, but no obvious change was observed for the coated membrane except increased hydrophilicity and permeate flux. Most importantly, the amount of bacteria attachment was found to reduce significantly (68%) on the membrane coated with nano spinel, which indicates the successful application of nano CuAl2O4 spinel as a novel antibacterial agent for membrane modification without extra concern of copper toxicity.