3D printed GO-g-C₃N₄-geopolymer components with acid treatment for the removal of methylene blue from wastewater

In this work, the synthesized geopolymer was prepared using metakaolin and alkali activator, and during the geopolymerization process, g-C₃N₄ and different contents of GO were added to the geopolymer, and GO-g-C₃N₄-GP was finally obtained. These samples can remove methylene blue (MB) utilizing the synergistic effect of adsorption and photocatalysis. 10% GO-g-C₃N₄-GP had the best removal rate of 93.28% within 30 min, under visible light. The results confirmed that geopolymers can provide a reusable carrier for g-C₃N₄, and the presence of GO can hinder the recombination of charges and promote the migration of photogenerated electrons, further improving the photocatalytic performance. 10% GO-g-C₃N₄-GP was also used to 3D print a scaffold by using the direct ink writing technology. To improve the efficiency of MB removal, 3D printed samples were treated with acid, and the sample of the 3D printed 10% GO-g-C₃N₄-GP acid treatment was also effective in removing MB and facilitates the recovery of the active material. This work can provide a simple way for synthesizing green materials for removing organic dyes.