Photocatalytic removal of Malachite green dye from aqueous solutions by nano-composites containing titanium dioxide: A systematic review

Background: Malachite green (MG) is widely used as a fungicide, Bactericide parasiticide in the aquaculture industry, as a food additive, medical disinfectant, and also, as a dye for materials such as silk, leather, paper, etc. In this study, the photocatalytic removal of MG from aqueous solutions using TiO2-containing nanocomposites was reviewed. Methods: In this study, four databases (PubMed, Web of Science, ScienceDirect, and Scopus) were systematically searched to collect studies on the decomposition of MG using nanocomposites containing TiO2 under UV light radiation. Results: In total, 10 related and eligible studies were selected. Based on the results, TiO2 was doped with iron, Sn, Ag, Si, and Ni. The highest percentage of photocatalytic decomposition for MG was observed in Sn > Ni > Ag > Fe > Si. The removal efficiency of MG in the studied papers was between 75%-100%. Conclusion: Recombinant nanocomposites had a higher dye removal percentage than uncombined ones because they play an important role in the photocatalytic process of dye, by producing free radicals.