Geopolymer membrane – photocatalyst coupling for textile wastewater treatment

This article presents the coupling of a geopolymer membrane (GM) with a photocatalyst (TiO₂), to combine filtration and photodegradation during wastewater treatment, using methylene blue as a model. The GM was prepared through the geopolymerization of metakaolin and alkali activator with pore modification through direct foaming. The photocatalyst TiO₂ was impregnated into the GMs, with loadings of 2.5, 5 and 10 wt%. The influence of TiO₂ addition on the characteristics of the membranes was investigated using several techniques (SEM, XRD, FTIR and open porosity determination techniques). The addition of TiO₂ influenced the porosity as well as the performance of GMs. In terms of methylene blue filtration-degradation, the TiO₂ loading exhibited its influence in a distinctive manner. The GM-TiO₂ 10 wt% exhibited complete rejection with very low hydraulic permeability, owing to the lowest open porosity. The GM-TiO₂ 5 wt% inferred the highest improvement on hydraulic permeability with a consistent rejection value.