Study on removal of organic matters in water by PVA modified PA-TFC nanofiltration membrane

Polyvinyl alcohol (PVA) modified polyamide thin film composite (PA-TFC) nanofiltration membranes were prepared by the interfacial polymerization of trimesoyl chloride (TMC), piperazine (PIP) and PVA on polysulfone supporting membranes, and were used for separating organic compounds from water. The results show that composite nanofiltration membranes are effective in retaining negatively charged organic compounds with molecular weight higher than 100 Da. For example, rejections to tyrosine, salicylic acid, and terephthalic acid were 63%, 77% and 97%, respectively. The effect of operation pressure, feed temparature, pH value and salt concentration on separation performances was also studied. It is found that both the flux and rejection of PVA modified PA-TFC nanofiltration membranes increase with increasing feed temparature and pH value, and decrease with increasing salt concentration. In detail, the flux and rejection of PVA modified PA-TFC nanofiltration membranes are J(water) = 33.9 l/m(2)h, R-chromic acid = 99.5% and R-NaCl = 17.0% in simulated dye wastewater treatment at 25 degrees C and 0.6 Mpa operating pressure, indicating that they are efficient in separating of negatively charged organic compounds and inorganic salts.