Modelling of fluidised-bed reactor by differential evolution optimization for phenol removal using coconut shells based activated carbon

Abstract

Abstract Phenol is one of the major pollutant released to water resources from manufacturing industries engaged in textile processing, petrochemical production, oil refining, etc. These phenolic compounds are water soluble and being highly toxic has adverse effects on aquatic life and environment. Removal of phenols from wastewaters has become mandatory due to stringent environmental regulations. Adsorption technique found to be effective process compared to other pollutant removal techniques, whereas its applications is limited due to high cost of adsorbents. In this research study, in a fluidised-bed reactor a low cost and easily available agricultural waste of activated carbon from coconut shells, were utilized as adsorbent to study its viability and efficiency for removal of phenol. The operating parameters such as superficial liquid velocity, contact times, feed phenol concentrations and carbon bed heights that influence the performance and characteristics of a fluidised-bed reactor were analyzed systematically. The efficacy of the reactor was evaluated for phenol removal with kinetic and equilibrium studies. The experimental adsorption data were examined by the various isotherm models and the corresponding adsorption rate values were interpreted with linear and non-linear kinetic models. A novel inverse modelling technique based on differential evolution optimization was implemented to estimate the kinetic parameters and non-linear model depicting the relation between the phenol removal efficiency as a function of operating parameters. It was observed from the experimental studies that almost 96% phenol removal can be achieved with lower activated carbon loadings as well as shorter residence time. These experimental results also revealed that coconut shell based activated carbon is a viable cheaper adsorbent for phenols removal from effluent wastewater.