Fabrication of Antibacterial Mixed matrix Membranes Using zinc Oxide and Copper Oxide Nanoparticles and ZnO/CuO Nanocomposite

Hypothesis:

Ultrafiltration (UF) membranes play a vital role in chemical processes through the separation of high molecular weight compounds, but suffer from a fouling phenomenon in which materials precipitate or adhere on the membrane surface; since the UF membrane feed is susceptible to the growth of microorganisms, biofouling can occur more often, which reduces the membrane performance. Some methods have been suggested to overcome the biofouling phenomenon which one of the best methods is the application of nanoparticles in the membrane.

ZnO and CuO nanoparticles and ZnO/CuO nanocomposite at three different concentrations (1, 3 and 5% by weights) were used to improve the antibacterial properties of PVC membrane. First, nanoparticles were synthesized through co-precipitation method and characterized by XRD and FTIR analyses. Then, the mixed matrix membranes were prepared and their properties were investigated in terms of permeation flux, porosity and contact angle. 

To study the antibacterial properties of the fabricated membranes, the disk diffusion method using Escherichia coli as gram-negative model was applied. The membrane containing 5% (by weight) ZnO with clear zone diameter equal to 9 mm and the membranes containing 3% (by weight) ZnO and 5% (by weight) CuO with clear zone diameter equal to 8.1 mm showed the best antibacterial activities. The results showed that the synthesized nanoparticles can improve the characteristics of the PVC membranes such as hydrophilicity (reducing contact angle from 86.28° to 67.55°) and impart antibacterial activities in the membranes. This method can be utilized to reduce the biofouling of membranes in the separation processes.