TiO2 nanoparticles coated forward osmosis membranes for treatment of industrial textile effluent

Abstract

Textile wastewater occur as demanding water bodies to be treated by membrane separation due to the complex composition and presence of reactive constituents such as heavy metals and salts as well as nutrients, e.g. nitrogen, sulphate and phosphate. Numerous combination of osmosis process with photocatalysts has been experimentally conceived for the water and wastewater treatment and reuse of textile wastewater. The present work was devoted to study the operating feasibility using photocatalyst as TiO2 nano-particles were coated onto two commercially available FO membranes, a cellulose triacetate (CTA) membrane and an aquaporin (AqP) membrane through a specially designed 3-(trimethoxysilyl) propyl methacrylate–polymethyl methacrylate–bromide (MEMO–PMMA–Br) monomer chain as an alternative forward osmosis treatment method of conventionally treated wastewater discharged from textile plants. Effects of dye concentration, dissolved ions and TOC and reactive dye removing were studied. An initial water flux (Jw) of 18.38 L m−2 h−1 with a dye rejection of 99.9% has been demonstrated by using 1 M NaCl as the draw solution and synthetic textile wastewater containing reactive textile dyes (black, blue and red) 200, 400, 600, 800 ppm, inorganic salts, varying amounts of PVA and HCOH as interferences in the feed under the FO mode. The water flux of both membranes and the performance of the CTA membrane were greatly enhanced after surface modification. The experiments also show that CTA membrane gives higher water flux than aquaporin membrane for forward osmosis operation of synthetic textile wastewater. The increase in water flux for aquaporin is about 5.13% than CTA.