Development and Testing of Robust 3D Printed ZnO/Clay Photocatalysts for Sustainable Wastewater Treatment.

Contamination of water resources with organic pollutants is a serious environmental problem. Degradation of organic pollutants using photocatalytic materials is a promising method of wastewater treatment. In this work, we report on the fabrication of novel 3D printed (3DP) ZnO/Clay materials to be used as efficient photocatalysts for the degradation of methylene blue (MB). Extrusion-based direct ink writing technology was utilized to print the scaffolds. The synthesized scaffolds were thoroughly characterized using the analytical techniques of Brunauer-Emmett-Teller, Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The photocatalytic activity was studied by measuring the photodegradation of MB under simulated solar radiation. The synergistic effects of adsorption and photodegradation resulted in a 100% removal efficiency of MB within 40 min by the 3DP catalyst. The reported catalysts require minimum time for MB degradation with high pollutants removal efficiency, and therefore, no further treatment is required after usage for the catalytic experiment. The 3DP catalysts also demonstrated excellent stability during the reusability test, where performance of the catalysts was assessed for the degradation of MB using several consecutive cycles without any treatment or regeneration. This work can provide a way for preparing efficient and environmentally friendly photocatalysts.