Kinetic modeling for phenol degradation using photo-impinging streams reactor

Abstract

In the present study, a novel kinetic model has been proposed for photocatalytic degradation of wastewater. In the first step, statistical experimental designs have been used to optimize the process of phenol degradation in a photo-impinging streams reactor. The crucial parameters, namely phenol concentration, catalyst loading, pH, and slurry flow rate, were selected for process optimization, applying central composite design. The analysis results indicated that interactions between catalyst loading and pH significantly affect phenol degradation. The predicted data showed that the maximum removal efficiency of phenol (99 %) could be obtained under the optimum operating conditions (phenol concentration = 50 mg l−1, catalyst loading = 2.1 g l−1, pH 6.2, and slurry flow rate = 550 ml min−1). These predicted values were then verified by certain validating experiments. Residence time distribution (RTD) of the slurry phase within the reactor was then measured using the impulse tracer method. A number of different assumptions were made, i.e., continuous stirred tank reactors (CSTRs) in series model and gamma distribution model with bypass (GDB). A comparison made between the sum of the square errors for experimental and predicted RTD values in case of each flow model revealed that both CSTRs in series model and GDB were proper descriptions for reactor behavior. The CSTRs in series model and RTD data were applied in conjunction with the phenol degradation kinetic model to predict the coefficients of the reaction rate.