Akademik Veri Yönetim Sistemi
Journal of the Faculty of Engineering and Architecture of Gazi University, cilt.39, sa.1, ss.233-242, 2023 (SCI-Expanded)
(Table Presented). Purpose: The aim of the study is to optimize TiO2 production conditions via Box-Behnken experimental design method in order to obtain high photocatalytic efficiency for 2,4 dichlorophenoxyacetic acid (2,4 D) degradation. Theory and Methods: TiO2 samples were produced according to the Box-Behnken Experimental Design matrix by changing three different parameters (Titanium isopropoxide (TIP) amount, HNO3 concentration and aging time). Produced TiO2 samples were used for degradation of 2,4 dichlorophenoxyacetic acid, then, the relationship between the production parameters and degradation rate is modelled. Table A shows the the design matrix, TiO2 production conditions, experimental and model degradation rate. Results: Fifteen TiO2 samples were synthesized by applying the Box-Behnken Experimental Design method and obtained photocatalysts were used in the photocatalytic degradation of 2,4 Diphenoxyacetic acid (2,4 D). The 2,4 D degradation rates obtained as a result of experiments with TiO2 produced at different conditions were transferred to the Design-Expert program and a model equation giving the relationship between production parameters and degradation kinetics was developed. The statistical significance of the developed model was evaluated by ANOVA, the model was significant over 95%. The most effective production parameter was the amount of TIP, then the aging time, and finally the amount of acid. As a result of the optimization made by using the Design Expert program, two different optimum process conditions were determined. In the first optimum condition, OPT-1; TIP amount: 24.08mL, HNO3 concentration: 3.53 M and aging time: 2.29 hours, in OPT-2; TIP amount: 10.33mL, HNO3 concentration: 0 M and aging time: 19.51 hours. In order to verify these parameters, TiO2 was synthesized at the optimum conditions, and used in photocatalytic degradation experiments. The highest degradation efficiency (about80%) and rates of 0.0084 and 0.0085 min-1 were obtained. All degradation kinetics data fitted the Langmuir-Hinshelwood kinetic model. XRD, BET surface area and size analyzes of optimum TiO2 photocatalysts were performed and it was found that they have similar properties with commercial TiO2. Conclusion: By optimizing the TiO2 production parameters via experimental design methodology, the use of acid amount is reduced to zero or the aging time is reduced to the lowest, then, a very high 2,4D photocatalytic efficiency has been achieved.