Visible-Light-Driven Photoreduction of Cr(Ⅵ) by Waste-Based Cu_2O Photocatalyst from Waste Printed Circuit Boards

摘要

Photocatalyst is a key factor to affect the photoreduction performance. However, the cost of preparing catalysts is relatively high and can be reduced by using waste-based materials. In this study, waste printed circuit boards (PCBs) were used as copper sources to prepare waste-based Cu2O photocatalyst for photocatalytic reduction of Cr(VI) by chemical precipitation method. Under visible light, the influence factors of photocatalytic reduction activity, such as light intensity, pH, and catalyst dosage, were investigated. Then, the effects of photocatalytic reduction of Cr(VI) by pure Cu2O, purified Cu2O and waste-based Cu2O photocatalysts were compared. The result indicated that the photocatalytic reduction of pure Cu2O and purified Cu2O were similar, higher than that of waste-based Cu2O. X-ray diffraction (XRD) analysis indicates that no new phases were formed in the three catalysts, but their morphologies observed by scanning electron microscope energy-dispersive X-ray spectroscopy (SEM-EDS) was found that the pure Cu2O and purified Cu2O are cubic, whereas the waste-based Cu2O is spherical and contains impurity Sn. It is considered that morphologies and impurity of the catalysts are the key factors for photocatalytic reduction efficiency. Finally, the electron transfer rate and the photocurrent response performance verified that the photocatalytic effect of pure Cu2O and purified Cu2O were better than that of waste-based Cu2O. It is believed that the copper from waste PCBs can be used as high value-added copper material catalysts by an effective preparation process.