Preparation and characterization of a PVA/PSf thin film composite membrane after incorporation of PSSMA into a selective layer and its application for pharmaceutical removal

A thin film composite (TFC) membrane was synthesized by coating a layer of poly (vinyl alcohol) (PVA) cross linked with Glutaraldehyde on a polysulfone (PSf) ultrafiltration support membrane. The effect of the incorporation of polyelectrolyte poly (4-styrenesulfonic acid-co-maleic acid) (PSSMA) into the PVA matrix at concentrations of 0% to 3% was investigated. The TFC membranes were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), attenuated total reflection Fourier transform infrared (ATR-IR) spectroscopy, contact angle and zeta potential measurements. The rejection rates were measured for Na2SO4, MgSO4 and NaCl salts and cephalexin, amoxicillin, ibuprofen and povidone iodine (PVP-I) pharmaceuticals. The effect of molecular weight and size, hydrophobicity, and electrical charge of the pharmaceuticals on the rejection of the TFC membranes was also investigated. It was found that incorporation of PSSMA into the PVA layer could increase membrane pure water flux (PWF). The results revealed that the addition of 1% PSSMA (TFC1) increased PWF from 6.8 to 141/m(2) h and showed comparable rejection rates for all membranes. For this sample, rejections of 99%, 97.7%, 93.8% and 74% were obtained for cephalexin, amoxicillin, PVP-I and ibuprofen, respectively. The effects of pH, transmembrane pressure and feed concentration on pharmaceutical separation performance were also studied. The rejection of ibuprofen increased from 74.1% to 97.2% after an increase in pH from 7 to 9. Near 100% rejection for cephalexin and amoxicillin and 80% for ibuprofen at a 20 ppm feed concentration showed the ability of the membrane for efficient pharmaceutical removal at low concentrations. An increase in transmembrane pressure increased the rejection of ibuprofen and PVP-I. For cephalexin and amoxicillin, a plateau occurred in the range of 97-99%.