Photocatalytic reduction of Cr(VI) over cinder-based nanoneedle in presence of tartaric acid: Synergistic performance and mechanism
Xinnian Xia , Wenwu Yang , Zhenfei Yang , Luhua Shao , Sijian Li , Yutang Liu
DOI:10.1016/j.jes.2021.02.006
Received December 11, 2020,Revised , Accepted February 03, 2021, Available online February 24, 2021
Volume 33,2021,Pages 194-204
Cr(VI) is a common heavy metal ion, which will seriously harm human body and environment. Therefore, the removal of Cr(VI) has become an attractive topic. In this work, cinder was used as a raw material to synthesize a nanoneedle material: γ-([email protected]) (γ[email protected]). The physicochemical properties of γ[email protected] were thoroughly characterized, and its effectiveness as a catalyst for photocatalytic reduction of Cr(VI) was evaluated. The results showed that Cr(VI) could be efficiently reduced by γ[email protected] in the presence of tartaric acid (TA) under visible light. The variable factors on the reaction were investigated in detail, and the results showed that under optimal conditions (γ[email protected] 0.4 g/L, TA 0.6 g/L, pH 2), Cr(VI) was completely reduced within 7 min. Besides, scavenger experiments and EPR proved that O2• — and CO2• — played a significant role in the photocatalytic reduction of Cr(VI). TA acts as a sacrificial agent to trap the holes and generate strong reducing free radicals: CO2• —. Dissolving O2 could react with electrons to generate O2• —. This work discussed the performance and mechanism of photocatalytic reduction of Cr(VI) in detail, which provided a new idea for the resource utilization of solid waste and the treatment of heavy metal sewage.
