Preparation of mesoporous activated carbon from coconut frond for the adsorption of carbofuran insecticide

This paper provides a scientific research about the novel activated carbon produced from coconut frond for the removal of toxic pesticide carbofuran. The coconut frond was chemically modified by H3PO4 with an impregnation ratio of 1:1 and later activated at 500 °C for 2 h. The produced coconut frond activated carbon (CFAC) were characterized by surface area measurement, Fourier transform infrared spectroscopy and scanning electron microscopy. The CFAC had a BET surface area of 483 m2/g and a cumulative pore volume of 0.21 cm3/g. Over 80% of 250 mg/L carbofuran was adsorbed within 4 h at 30 °C and the adsorption was not dependent on pH due to the nonionic nature of carbofuran. The adsorption kinetic was best represented by the pseudo-second-order model. The adsorption equilibrium data fitted best to the nonlinear Freundlich isotherm model. Thermodynamic parameters obtained showed that the adsorption was spontaneous and endothermic in nature. Adsorption mechanisms were analyzed using intraparticle diffusion and Boyd kinetic models, and film diffusion was confirmed as the rate-controlling step. These results indicate that CFAC is an efficient adsorbent for the removal of the nonionic pesticide, carbofuran from aqueous solution.