RESUMO
Tramadol is an analgesic drug that is mainly excreted in the urine. The entry of Tramadol into water samples causes their biological contamination. Therefore, three catalysts such as bismuth ferrite, cobalt-doped bismuth ferrite, and a magnetized Keggin type of polyoxometalate (α-Fe2O3@phosphotungstic acid), were synthesized as photocatalysts to degrade Tramadol in water samples. The morphology and properties of the prepared photocatalysts were evaluated using several techniques. Effects of several factors, including tramadol concentration, pH, hydrogen peroxide concentration, and photocatalyst amount, were studied and optimized by a design experiment procedure based on Box-Behnken design for reducing the number of experiments and cost and investigating the interactions between factors in the photocatalytic degradation process of Tramadol. These factors were optimized for each prepared photocatalyst individually. Under the optimum conditions, the percentages of tramadol degradation and kinetics of the degradation process were evaluated in the presence of each photocatalyst. The tramadol degradation percentages using bismuth ferrite, cobalt-doped bismuth ferrite, and α-Fe2O3 @phosphotungstic acid were 81.10% for 120 min, 90.63% for 80 min, and 91.32% for 80 min, respectively. The rate constants of tramadol degradation were 0.0145, 0.0329, and 0.0312 min-1 for bismuth ferrite, cobalt-doped bismuth ferrite, and α-Fe2O3 @phosphotungstic acid, respectively. The results indicated the highest percentage of tramadol degradation and rate of the degradation process were obtained using α-Fe2O3 @phosphotungstic acid and cobalt-doped bismuth ferrite, respectively.
