Composite nanofiltration membranes prepared by interfacial polymerization with natural material tannic acid and trimesoyl chloride

Natural material tannic acid was first selected as polyphenol monomer to fabricate the novel composite nanofitration membranes. There was chemical cross-linking reaction took place between the phenol groups of tannic acid and acyl chloride groups of trimesoyl chloride (TMC) in the water/oil interfacial zone. The polyester thin layers from tannic acid and TMC interfacial polymerization on porous ultrafiltration membrane support were characterized by scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and water contact angle measurement. The effects of post treatment temperature and reaction time, and monomer concentrations in aqueous and organic solutions on water permeability, and rejection of dyes and inorganic salts of the nanofiltration membranes were studied, respectively. Tannic acid and TMC composite nanofiltration membranes had low flux decline ratios and high flux recovery ratios without chemical cleaning in the antifouling evaluation experiments. The excellent antifouling properties and chemical stability of tannic acid and TMC composite nanofiltration membranes made them have potential uses in wastewater treatment.