Photocatalytic treatment of Cr(VI) with ZrO2 and application of by-products as ethane dehydrogenation catalyst

ABSTRACT The recovery of Cr(VI) from the solution and the utilization of by-products are significant for waste-water treatment and environmental protection. In this study, the amorphous ZrO 2 was prepared using a solvothermal method and used to treat the wastewater containing Cr(VI). Amorphous ZrO 2 is effective for the photocatalytic reduction of Cr(VI). Without a sacrificial agent, 20 mL potassium dichromate solution (20 mg/L) is reduced to almost 0 mg/L within 10 min. Moreover, the by-products obtained from this process exhibit good performance in the catalytic dehydrogenation of ethane coupled with the reverse water–gas reaction. The maximum yield of ethylene is 12.9%, and the service life of the catalyst reached 160 min. Catalyst deactivation is caused by carbon deposition, and the deactivated catalyst is regenerated by roasting in the air. The feasibility of this green process is demonstrated, including the one-step photocatalytic reduction of Cr(VI) and utilization of the by-product as an ethane dehydrogenation catalyst.