Preparation of Nano-Cu2O/Pearl Shell Composites for Treating Organic Dyes

Waste pearl shells were activated and used as carriers to prepare a nano-Cu2O/pearl shell composite photocatalyst by in situ hydrolysis. The composites were characterized by X-ray diffraction, X-ray photoelectron spectrometer, scanning electron microscopy, and UV-Vis diffuse reflectance spectrometer. Reactive red dye B-3G solutions were used as simulate wastewater to investigate the photocatalytic performance under visible light irradiation. The loaded Cu2O particles had an average diameter of 16.8 nm, were oval in shape and have absorption bands in the UV and visible region similar to those of pure Cu2O particles. The nano-Cu2O/pearl shell composites had much higher photocatalytic activities than pure Cu2O. Over 98% of the B-3G solutes were decolorized by these composites under the conditions of pH = 6.0–12.0, reaction time = 90 min, and B-3G concentration ≤ 220 mg/L. The photocatalytic decolorization of B-3G followed pseudo-first order kinetics. The formation mechanism of the nano-Cu2O/pearl shell composites was studied by Fourier transform infrared spectroscopy. It involved the interaction and combination of Cu2O and CaO.