The effect of sodium formate mediated double regulation in TiO2 photocatalytic reduction of cadmium

Investigating on the effect of sodium formate mediated double regulation in TiO2 photocatalytic reduction of cadmium is firstly reported. Multiple characterized methods were used to characterize and confirmed the successful reduction of Cd2+ to the form of metal elements by sodium formate-P25 system. The metal elements were attached to the surface of the composite photocatalyst were directly observed by SEM. The removal efficiency of Cd2+ for the composite photocatalyst was tested. When the addition of sodium formate was 1 g/L, the maximum removal rate of Cd2+ was 94.8% within 10 min. Further experiments showed the mechanism and activity of the combined catalysis of sodium formate and photocatalysis and the role of composite photocatalyst in photocatalytic activity. This is mainly due to the bidentate chelation between sodium formate and TiO2 which makes it possible to adsorb heavy metal ions and the transfer of photo-generated electrons on the bidentate complex, which improves the survival time of the electrons and reduces the metal ions.