Removal of natural organic matter from water using a nano-structured photocatalyst coupled with filtration membrane

Abstract

A study of the characteristics of a novel photocatalyst indicated that it consisted of 17.3 nm nano size (average) TiO₂ in the anatase phase and porous Fe₂O₃. SEM results revealed that nano size TiO₂ was uniformly deposited onto the surface of Fe₂O₃ to form a bulk photocatalyst, as TiO₂/Fe₂O₃. The porous TiO₂/Fe₂O₃ catalyst had a BET surface area of 168 m²/g, which is three times higher than that of commercial TiO₂. The experimental results indicated that the suspended TiO₂/Fe₂O₃ photocatalyst in a photocatalytic oxidation (PCO) reactor was effective in removing TOC at 61.58% and color400 at 93.25% at 180 min illumination time, under 0.4 g/l catalyst loading and pH 7. Experimental results also revealed that pH at 7 and TiO₂/Fe₂O₃ loading at 0.4 g/l was the optimum condition for removal of humic acids using a PCO reactor. Experimental results clearly indicated that the permeate flux rate of the ultrafiltration (UF) membrane was improved and the filtration membrane fouling phenomenon was reduced with the addition of TiO₂/Fe₂O₃ photocatalysts to the UF membrane system. It was found that increasing the filtration time from 40 min to 185 min, the improvement to the permeate flux rate was from 57 to 83 L/hr.m².