The effect of silica-doped graphene oxide (GO-SiO₂) on persulfate activation for the removal of Acid Blue 25

The release of synthetic dyes into water bodies poses many environmental issues, and their removal is a necessity. Advanced oxidation processes (AOPs) can be employed for removal, in many of which a catalyst is used. graphene oxide (GO) is a viable catalyst due to its distinctive structural properties; however, it is reportedly incapable of effectively activating persulfate. Thus, this study delves for the first time into the influence of doping silica on enhancing GO's catalytic performance to activate persulfate for decolorizing Acid Blue 25 (AB25). Based on the results, an equal weight proportion of GO to silica was selected as the most efficient ratio. In addition, pH had no significant effect on removal efficiency, while temperature had the highest impact. Within 150 min with 0.075 gr/L of GO-SiO₂ as the catalyst and 1 gr/L of Na₂S₂O₈ as the oxidant, the investigated process removed Acid Blue 25 up to 82%, which was 9% higher than when GO alone was used as the catalyst. As for COD removal, the contribution of doping silica was more significant and led to 37% COD removal, which was 17% higher than when GO alone was used.