Modification of Structural Properties of Nanocomposite Membranes for Improving Dye Separation from Textile Effluents

Surface and structural modification of membranes in order to improve their filtration properties have been one of the vast research areas in the field of membranes in recent years. Nanomaterials are most widely used for modifying the surface and structure of the membranes. In this study, carboxylic acid and sulfate carboxylic groups were deposited on the surface of zirconia nanoparticles in order to improve their arrangement within the membrane matrix. Then, the structure and behavior of the nanocomposite membrane was compared with those of raw membrane. ZrO2, Zr-COOH and Zr-SO4 nanoparticles were added to the polysulfone (PSf) membrane substrate, and the effect of the surface, structural and filtration properties of raw and nanocomposite membranes were compared in relation to their textile wastewater treatment performance. For this purpose, PZC, EDX, SEM, AFM, CA and porosity analysis as well as viscosity, flux recovery and dye rejection measurement were performed. The results of analyses showed that the presence of Zr-COOH nanoparticles led to greater finger pores, smaller size of the nanoparticles, and the presence of Zr-SO4 nanoparticles led to fewer finger pores, less porosity and larger nanoparticle size. The presence of the functional groups increased the number of nanoparticles in the skin layer of the membrane and improved the membrane surface properties. Analysis of variance obtained using RSM method for porosity and contact angle data showed that the most effective factor on porosity and contact angle is nanoparticles concentration. By increasing the concentration of ZrO2, Zr-COOH and Zr-SO4 nanoparticles from 0 to 2 wt%, the flux recovery was increased by 15, 25 and 45%.