Bio-calcium oxide derived from eggshell-titanium dioxide@graphene oxide for photodegradation of dyes and antibacterial activities

Abstract

The utilization of calcium oxide (CaO) derived from calcined eggshells is considered a primary source of materials for semiconductor incorporation, which is a facile and environmentally friendly method. This work introduces a novel composite, namely calcium oxide-titanium dioxide@graphene oxide (CaO-TiO₂@GO) with photodegradation efficiency of various organic pollutants such as crystal violet (CV), malachite green (MG), rhodamine B (RhB), and methyl orange (MO). The results showed that the synergistic efficiency of the combination of GO and CaO-TiO₂ increased the adsorption-photodegradation efficiency with the removal of CV, MG, RhB, and MO of 99.72, 99.41, 97.21, and 80.09 %, respectively. The kinetics of dye photodegradation follows a pseudo-first-order kinetics model, the reusability toward CV removal reaches over 85 % after 5 cycles, and the free radical scavenging experiment identifies that the •O₂⁻ plays a major role in the photodegradation mechanism. In addition, the fundamental antibacterial performance toward strains of Pseudomonas aeruginosa and Bacillus subtilis was reported with antibacterial inhibition diameters of 12.1 and 11.2 mm, respectively.