3D-printed green and low-cost porous g-C₃N₄/geopolymer components for the removal of methylene blue from wastewater

In this study, we report that geopolymer materials containing different amounts of graphitic carbon nitride (g-C₃N₄) (C₃N₄/GP) can remove methylene blue (MB) using the synergistic effects of adsorption and photodegradation. A geopolymer containing 3 wt% g-C₃N₄ (3 wt%C₃N₄/GP) had the best MB removal efficiency of 94.62% within 60 min, under visible light. The results showed that geopolymers can act as carriers for g-C₃N₄, and the relative amount of adsorbent and photocatalyst influences the removal of MB. 3 wt%C₃N₄/GP was also used for additive manufacturing by using direct ink writing technology. In order to improve the efficiency of MB removal, a pore-forming agent (K12) was added in the synthesis process to prepare three-dimensional-printed porous C₃N₄/GP. The results showed that the porous C₃N₄/GP was effective in removing MB. This work provides a simple strategy for preparing efficient and green materials for removing organic pollutants.