Effect of chlorine substitution on the removal of phenols by activated carbon

Abstract

A comparison of the removal of substituted phenols (2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol) with phenol using adsorption process on activated carbon has been investigated. The adsorption data was modeled using Langmuir and Freundlich equations and the Langmuir model was found to be the best fit. The removal of phenols by activated carbon followed a trend based on number of chlorine substitution with order: phenol < 2-chlorophenol < 4-chlorophenol < 2, 4-dichlorophenol. Substantial uptake of the phenols on activated carbon was observed and was found to be 0.83, 0.91, 0.93 and 1.51 mmol/g for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol, respectively. Pseudo-first order and pseudo-second order models were used to analyse the kinetic data and the process was found to follow pseudo-second order kinetic model.

Keywords

• activated carbon
• adsorption
• chlorophenols
• phenol
• kinetics