Phenol contaminated water treatment by photocatalytic degradation on electrospun Ag/TiO2 nanofibers: Optimization by the response surface method

Abstract

Photocatalytic water treatment with solar radiation can protect the environment by removing harmful pollutants from water and using a source of clean energy. This idea exactly is an application of the “water-energy-environment-nexus” for sustainable development. In this research, Ag/TiO2 nanofibers were synthesized using the electrospinning method and examined for phenol photocatalytic degradation under the visible light. Response surface method (RSM) was used for the design of experiment (DOE) for statistical optimization of three factors including pH, initial phenol concentration, and concentration of photocatalyst in water. The results show that the quadratic model is the best one for relating phenol degradation to these three factors and their interactions. Analysis of variance (ANOVA) shows that phenol concentration, pH, the interaction of phenol concentration and pH, square of phenol concentration, and square of catalyst dosage have a significant effect on the degradation of phenol. Three optimization scenarios were chosen; First: unconditional maximizing of the phenol degradation that results in the degradation of 92.91 % at optimal values of phenol concentration = 5.62 ppm, catalyst dosage = 2.06 g/L, and pH = 7.87. Second: multiobjective optimization with two simultaneous goals of minimizing catalyst dosage and maximizing the degradation which results in 82.65 % degradation and catalyst concentration of 0.65 g/L. Third: maximizing the degradation by targeting natural pH for water that results in 78.32 % of phenol degradation.