Abstract:
In this paper, photo-catalytic process for treatment of phenolic wastewater by TiO2 nano powder immobilized on concrete surface
in a recirculation hydraulic flow was investigated. The process affected by different operational conditions that the optimum ones
could be obtained from variables interchange. Taguchi method as a proper method for design of experiments and optimization
was used to find optimum conditions. Selected five parameters at four levels were consists of initial phenol concentration, UV
lamps power, pH, TiO2 concentration and UV lamp distance from concrete surface. L16 (45) orthogonal array for experimental
planning and the bigger-the-better response category was applied to obtain optimum conditions. Analysis of variance (ANOVA)
was used to determine the most significant parameters affecting the removal efficiency of phenol. Based on the S/N ratio, influent
phenol concentration and solution pH had the most effect in removal efficiency and distance of UV lamps to concrete surface was
found to be an insignificant parameter. Long term use of process showed that decrease in phenol removal efficiency was less than
5% and SEM-EDX confirmed TiO2 nano photo-catalyst immobilized on concrete surface after several process cycles.