Kinetic study of acetaminophen degradation by visible light photocatalysis

In this work, a novel photocatalyst K-3[Fe(CN)(6)]/TiO2 synthesized via a simple sol-gel method was utilized to degrade acetaminophen (ACT) under visible light with the use of blue and green LED lights. Parameters (medium pH, initial concentration of reactant, catalyst concentration, temperature, and number of blue LED lights) affecting photocatalytic degradation of ACT were also investigated. The experimental result showed that compared to commercially available Degussa P-25 (DP-25) photocatalyst, K-3[Fe(CN)(6)]/TiO2 gave higher degradation efficiency and rate constant (k(app)) of ACT. The degradation efficiency or k(app) decreased with increasing initial ACT concentration and temperature, but increased with increased number of blue LED lamps. Additionally, k(app) increased as initial pH was increased from 5.6 to 6.9, but decreased at a high alkaline condition (pH 8.3). Furthermore, the degradation efficiency and k(app) of ACT increased as K-3[Fe(CN)(6)]/TiO2 loading was increased to 1g L-1 but decreased and eventually leveled off at photocatalyst loading above this value. Photocatalytic degradation of ACT in K-3[Fe(CN)(6)]/TiO2 catalyst system follows a pseudo-first-order kinetics. The Langmuir-Hinshelwood equation was also satisfactorily used to model the degradation of ACT in K-3[Fe(CN)(6)]/TiO2 catalyst system indicated by a satisfactory linear correlation between 1/k(app) and C-o, with k(ini) = 6.54 x 10(-4) mM/min and K-ACT = 17.27mM(-1).