Adsorption and photodegradation efficiency of TiO2/Fe2O3/PAC and TiO2/Fe2O3/zeolite nanophotocatalysts for the removal of cyanide

Abstract

The synthesized TiO2/Fe2O3 nanostructures supported on powder-activated carbon (PAC) and zeolite at different mole ratios of Fe3+/TiO2 were characterized by XRD, XRF, FESEM, EDX, TEM, FTIR, BET, and, PL analyses and their cyanide photodegradation mechanism was thoroughly discussed. The results confirmed not only TiO2/Fe2O3/PAC had higher photocatalytic and adsorption capability but also better structural stability and reusability for cyanide removal than TiO2/Fe2O3/zeolite. The first-order kinetics model indicated that the photodegradation rate using TiO2/Fe2O3/PAC was 1.3 times higher than that of TiO2/Fe2O3/zeolite. The response surface methodology (RSM) assessment showed that pH, irradiation time and initial cyanide concentration using UV/H2O2/TiO2/Fe2O3/zeolite system had more effects on the degradation, respectively; whereas the effectiveness of UV/H2O2/TiO2/Fe2O3/PAC process was highly influenced by initial cyanide concentration than the other two parameters. High R-2 and well-fitted residual plots approved the accuracy of the models in predicting the cyanide degradation efficiency using both the photocatalysts.