Prediction of carbofuran degradation based on the hydroxyl radical’s generation using the FeIII impregnated N doped-TiO2/H2O2/visible LED photo-Fenton-like process

Abstract

Hydroxyl radicals (OH) are the dominant reactive species during most photocatalytic reactions. Therefore, OH generation as an index could be beneficial in comparing the obtained results in different experimental setup designs, thereby providing new insights for understanding the photocatalytic mechanism. Heterogeneous photo-Fenton like processes are one of the most effective technologies for degradation of organic pollutants through OH production. Nevertheless, kinetic models that take into account the dependence of the contaminant degradation on OH generation under homogeneous oxidant supply, are still limited in such processes. In this paper, a photo-Fenton like reagent (FeIII impregnated N-doped TiO2 (FeNT)/H2O2) involving both heterogeneous and homogeneous phases was employed for carbofuran (CBF) degradation, frequently used pesticide in many developing countries from the carbamate group. In addition, a commercial visible LED lamp (Vis LED) with high power output was utilized as an innovative and efficient visible light source to simulate solar energy. Accordingly, a new kinetic model was proposed to predict CBF degradation in the FeNT/H2O2/Vis LED process under high Vis LED light intensities based on intrinsic reaction parameters, including the Vis LED light intensity, FeNT dosage, initial H2O2 concentration, and OH generation. The developed model was verified and validated successfully under various reaction conditions. However, a standard error ranging from 3% to 15% was observed at extreme cases such as high [FeNT] and I or low [H2O2]0 when comparing model predictions and experimental results. This is due to the use of averaged conditions to forecast the rate constants.