Optimization of Hydrogen Production over TiO2/Treated Zeolite Nanophotocatalyst using Response Surface Box-Behnken Design

In present study, the optimization of hydrogen production by water splitting over TiO2/treated clinoptilolite photocatalyst was investigated using Box–Behnken design (BBD) combined with response surface methodology (RSM). In the photocatalyst preparation, the combined ion exchange-alkaline treatment was used to achieve a chemical homogenous, reproducible and effective natural support. Moreover, 10 wt.% of TiO2 nanoparticles was loaded over zeolitic supports using facile and cost effective solid state dispersion (SSD) method in the presence of ultrasound irradiation. The characterization results indicated suitable optical and physico-chemical properties of the as-synthesized photocatalyst which making it effective in the water splitting reaction. The operational variables considered in Box-Behnken method included pH solution, photocatalyst dosage and sacrificial agent concentration. Based on the ANOVA results, all three process variables affect the hydrogen production. Among them, the most significant effect is attributed to pH solution. The application of the RSM resulted in the formulation of several models out which the quadratic model with the highest value of the determined R2 coefficients (R2=0.9967 and R2adj=0.9942) was adjudged to adequately fit the experimental data. By examining how the process variables and their interactions affect the response, it can be found that the maximum efficiency of hydrogen production was obtained at optimum conditions of alkaline solution pH of 10, catalyst dosage of 1.1 g/L and sacrificial agent concentration of 12.5 vol.%.