Modified coconut fiber used as adsorbent for the removal of 2-chlorophenol and 2, 4, 6-trichlorophenol from aqueous solution

Abstract

The aim of this work was to determine the potential application of adsorbent prepared from coconut fiber for the removal of organic water pollutants. Removal of 2-chlorophenol (2-CP) and 2, 4, 6-trichlorophenol (TCP) from aqueous solution by coconut fiber activated carbon (FAC) and acid treated coconut fiber activated carbon (ATFAC) was investigated. Equilibrium and kinetic studies were performed and the data was fitted to isotherm and kinetic models. Langmuir isotherm model fitted better than Freundlich to the adsorption data. The monolayer adsorption capacity of ATFAC (38.29 mg g-1 for 2-CP and 101 mg g-1 for TCP) at 250C was relatively higher as compared to that of FAC (37.11 mg g-1 for 2-CP and 49.80 mg g-1 for TCP). The adsorption trend was as follows: ATFAC (TCP) > ATFAC (2-CP) > FAC (TCP) > FAC (2-CP). The pseudo-second-order rate model fitted better to the adsorption kinetics as compared to the pseudo-first-order rate model in all the cases. Overall adsorption rate is controlled by film diffusion. The thermodynamic parameters (free energy, enthalpy, entropy changes) exhibited the feasibility and spontaneous nature of the adsorption process. The results of the study show that the carbon prepared from acid treated coconut fiber is more effective than thermally treated fiber in the removal of chloro phenols and can be used as a potential adsorbent for the removal of water pollutants.