Optimization of Photocatalytic Degradation of Phenol Using Simple Photocatalytic Reactor

Abstract

The phenol photocatalytic degradation was investigated using heterogeneous catalyst Ag-doped ZnO nanowires under UV irradiation. Ag-ZnO nanowires were immobilized on borosilicate glass via a simple hydrothermal technique. Preliminary photodegradation studies were performed with Ag-ZnO nanowires at various concentrations of phenol (10 - 60 mg/L) at undiluted pH. After determination of the optimal initial concentration (30 mg/L), additional parameters including pH and light intensity were investigated to optimize photodegradation of phenol for large-scale application. The experimental results illustrate that the kinetics of degradation of phenol are pseudo-first order. Based on the relationship, experimental model and empirical correlation were generated and compared for validity. The experimental data were found to fit a cubic model (linear in UV irradiation intensity, I , and cubic in pH), over ranges of 10 - 60 W (UV lamp power) and 2.7 - 11.0 (pH) with a coefficient of determination ( R 2 ) of 0.9934. This model, of the form K ( I , pH) = c 00 + c 10 I + c 01 pH + c 11 I pH + c 02 pH 2 + c 12 I pH 2 + c 03 pH 3 was found to yield a better fit than simpler (quadratic) or more complex (quartic) polynomial-based models considered. The model parameters c ij and corresponding 95% confidence intervals were obtained.