Photocatalytic oxidation of Reactive Red 195 by bimetallic Fe–Co catalyst: Statistical modeling and optimization via Box-Behnken design

Abstract

Response surface methodology (RSM) is an effective tool for process optimization with multi-complex operational factors. The present work aims to model and optimize the photocatalytic oxidation (PCO) parameters of Reactive Red 195 (RR195) dye decoloration with the SiO2-supported Fe–Co catalyst (FCS) derived from a novel catalyst synthesis method, fluidized-bed crystallization (FBC) process, using Box-Behnken design (BBD) as the RSM statistical model. The Fe–Co@SiO2 catalyst was successfully fabricated using the FBC process, and it showed good catalytic activity and performance toward the degradation of RR195. The extent of the effects of pH, H2O2 dosage (HD), catalyst loading (CL), and operating time (t) on the decoloration of RR195 was studied. Hence, the order of variable significance follows the sequence: pH > t > CL > HD. pH has the most significant effect among the variables for RR195 decoloration. The decoloration efficiency predicted by the BBD model was 88.3% under the optimized operation conditions of initial pH of 3.15, 0.76 mM H2O2, 1.18 g L−1 FCS and 59.4 min of operating time. The actual decoloration efficiency was very close to the predicted value indicating that BBD can efficiently be utilized to optimize RR195 degradation with FCS under the PCO system.