Modeling and kinetics study of acid anthraquinone oxidation using ozone: energy consumption analysis

An anthraquinone dye as a persistent organic material was eliminated by an environmentally safe method. In this work, decolorization of acid green 25 (AG25) was carried out using ozonation in a semibatch bubble column. Results showed that the process efficiency was affected by three operational parameters of influent ozone mass flow, initial AG25 concentration, and reaction time. Moreover, inhibitory effects of ethanol, 2-propanol, and carbonate as scavengers on the process efficiency were also evaluated. Kinetics study indicated that AG25 removal was a pseudo first-order reaction with respect to various concentrations of AG25, ozone, and radical scavenger. An artificial neural network (ANN) was developed to predict the process performance. The obtained weights from ANN were used for sensitivity analysis of the process. This analysis indicated that relative importance of influent ozone mass flow, initial AG25 concentration, and reaction time was 22, 14, and 64 %, respectively. Cost-effectiveness analysis of the process was implemented by calculating electrical energy consumption at various concentrations of AG25. Based on the results, the range of electrical energy consumption was found between 1.2 and 2.3 kWh/m³/order.