Optimization of visible-light photocatalytic degradation of acetaminophen by K3[Fe(CN)6]-modified TiO2

Visible-light photocatalytic degradation of acetaminophen (ACT), one of the most detected pharmaceuticals in aqueous environment, by K3[Fe(CN)6]-modified TiO2 was presented in this study. Mutlivariate analysis based on response surface methodology was employed to quantify the individual and interaction effects of three key process parameters, i.e. photocatalyst dosage (A), initial ACT concentration (B), and initial pH (C) at pre-determined ranges. Results revealed that among the process variables investigated, initial ACT concentration has the most significant effect, while interactions between photocatalyst dosage and initial ACT concentration (AB) as well as with initial pH (AC) also played important roles. Optimized conditions are obtained at photocatalyst dosage of 0.1 g/L, initial ACT concentration of 0.1 mM, and initial pH of 6.94. The optimized conditions were verified experimentally at 91.06% ACT removal rate, which is within 95% confidence interval of the proposed model. In addition, characterizations of the K3[Fe(CN)6]-modified TiO2 carried out by SEM-EDS, XRD and FTIR provide more structural information for the new visible-light active photocatalyst.