Polyester thin film composite nanofiltration membranes prepared by interfacial polymerization technique for removal of humic acid

Nanofiltration (NF) polyester thin film composite membranes have been prepared through interfacial polymerization using a microporous polyethersulfone membrane as support. The thin polyester layer formed on the top surface of the microporous support layer was produced by the reaction of 6%w/v of triethanolamine (TEOA) in aqueous solution and a solution containing trimesoyl chloride (TMC) for different reaction times (15, 25, and 35min). The performance of the membranes was then characterized using permeation experiments with 0.001-0.1M of salt solutions (NaCl and Na₂SO₄) and 15mg/l of humic acid solution as a model for natural organic matter (NOM), normally found in surface water. This study has shown that through the interfacial polymerization technique, the variation of reaction time at a constant monomer concentration of 6% w/v can affect the properties of the membrane produced and indirectly influences the membrane performance. Increasing the reaction time resulted in decreasing water permeabilities. However, a higher removal of humic acid was observed.