3D printing of green and environment-friendly rGO@ZnO/GP for removal of methylene blue from wastewater

In this work, we report the fabrication of geopolymer materials containing different amounts of reduced graphene oxide loaded on zinc oxide (rGO@ZnO/GP) to be used as efficient photocatalysts for the degradation of methylene blue (MB). The synergistic effects of adsorption and photodegradation resulted in a 92.56% removal efficiency of MB within 30 min by a geopolymer containing 56%rGO@ZnO (56%rGO@ZnO/GP). The results showed that the geopolymer matrix provided a reusable carrier for rGO@ZnO, and the presence of rGO could promote the migration of photogenerated electrons and hinder the recombination of charges, thereby enhancing the photocatalytic activity. The best performing material (56%rGO@ZnO/GP) was also used to 3D print a scaffold using Direct Ink Writing technology. The 3D printed 56%rGO@ZnO/GP was also an efficient photocatalyst for the degradation of MB, and the use of a structured catalyst facilitates the recovery of the active material. This work can provide a way for preparing efficient and environmentally friendly photocatalysts.

Automated summary

In this work, geopolymer materials with different amounts of reduced graphene oxide loaded on zinc oxide (rGO@ZnO/GP) were fabricated as efficient photocatalysts for the degradation of methylene blue (MB). The presence of rGO in the geopolymer matrix promoted the migration of photogenerated electrons and hindered the recombination of charges, resulting in a 92.56% removal efficiency of MB within 30 min by the 56%rGO@ZnO/GP. The 3D printed 56%rGO@ZnO/GP scaffold also exhibited efficient photocatalytic activity for the degradation of MB, and the structured catalyst facilitated the recovery of the active material.