Thermo-chemical sequestration of naphthalene using <i>Borassus flabellifer</i> Shell activated carbon: Effect of influencing parameters, isotherm and kinetic study

Abstract

The present research describes the removal of naphthalene from aqueous solution using one of the simplest agricultural wastes, Borassus flabellifer Shell activated carbon (BFS-AC) by adsorption. Adsorption was chosen due to its cost-effectiveness. The effect of operating parameters such as pH, time, initial concentration of naphthalene, BFS-AC dosage and temperature on the percent removal of naphthalene was determined. The optimum conditions obtained were pH of 7, contact time of 12 h for an optimum concentration of 200 mg/L with the addition of 8 g at a temperature optimum at 40°C attaining the maximum percent removal. The adsorption kinetics supported the Freundlich model with R2 value of 0.995 indicating multilayer adsorption. The chemical kinetic studies followed the pseudo second order mechanism. The characterization of BFS-AC was carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) which showed the enhanced porosity and crystallinity of the adsorbent which was mainly due to the surface modification carried out by chemical addition followed by thermal treatment. The initial and final naphthalene concentration after adding the
adsorbent was determined by using gas chromatography-mass spectrometry (GC-MS). The characterization thoroughly suggests the efficacy of B. flabellifer shell to efficiently sequester naphthalene from aqueous solution.

Keywords: Naphthalene, Borassus flabellifer, thermo-chemical, activated carbon, adsorption