Preparation and characterization of a novel PA-SiO2 nanofiltration membrane for raw water treatment

A novel nanofiltration membrane containing SiO2 nanoparticles was prepared with poly(amidoamine) (PAMAM) dendrimer and trimesoyl chloride (TMC) by interfacial polymerization on polysulfone (PSF) ultrafiltration membrane. The FTIR-ATR, FESEM, XPS, TGA and contact angle analyzer were employed to characterize the surface morphology, physical and chemical properties of PA-SiO2 membrane. The prepared conditions should be controlled as PAMAM concentration 0.2% (wt.), TMC 0.2% (wt.) and the interfacial polymerization time nearly 90s. The addition of nano-SiO2 in the skin layer improved thermal stability, hydrophilicity and enhanced the membrane permeation properties without loss of rejection rate. The order of salts rejection rate is Na2SO4 > MgSO4 > MgCl2 > NaCl, which indicated that the PA-SiO2 was nagatively charged. The zeta potentials for PA-SiO2 membranes were more negative than that of PA membrane for nano-SiO2 surface with more negatively charged hydroxyl groups. The nano-composite NF membrane is particularly suitable for treating acidic feeds and separating salt solution containing bivalent anions. The anti-fouling abilities were enhanced for PA-SiO2 membrane when treating with raw surface water.

► Preparation of nano-SiO2 modified NF and their application to raw water treatment in comparison with pure PA membrane. ► The composite membrane has excellent thermal resistance and hydrophility. ► Moderate modification improved permeation about 50% without loss of rejection rate. ► The anti-fouling property of modified membrane was enhanced in treating with raw water.