Jute (Corchorus olitorius) stick charcoal: a potential bioadsorbent for the removal of Cr(VI) from an aqueous solution

Abstract

This study investigated the performance of jute stick charcoal (JSC) as a biosorbent for the removal of hexavalent chromium [Cr(VI)] from an aqueous solution. The batch adsorption experiment was conducted by influencing various experimental conditions like contact time (5–240 min), pH (2–8), initial Cr(VI) concentration (10–100 mg/L), and JSC dose (2–10 g/L). The study result shows that maximum Cr(VI) removal (99%) was found at pH 2, 20 mg/L of initial Cr(VI) concentration, 8 g/L of the JSC dose, and 150 min of equilibrium contact time. Fourier transform infrared (FTIR) spectroscopy and a field emission scanning electron microscope (FE-SEM) were used to characterize the JSC surface characteristics. The Cr(VI) adsorption data of JSC were better described by the Freundlich (R2 = 0.995) and Halsey (R2 = 0.995) isotherm models. The maximum monolayer adsorption capacity of JSC was 11.429 mg/g. Kinetic adsorption data of JSC followed the pseudo-second-order model (R2 = 1.0) as compared with the pseudo-first-order model (R2 = 0.97) and this adsorption process was controlled by chemisorption with multi-step diffusion. Finally, this study revealed JSC as an effective adsorbent for Cr(VI) removal from an aqueous solution. HIGHLIGHTS Cr(VI) adsorption was examined using charcoal derived from a jute stick.; Cr(VI) adsorption onto jute stick charcoal (JSC) increased with an increase in the JSC dose.; Equilibrium data followed Freundlich and Halsey isotherm models and the highest monolayer adsorption capacity of JSC was found at 11.429 mg/g.; Kinetic data followed pseudo-second-order kinetic.; Surface functional groups of JSC influence the Cr(VI) adsorption onto JSC.;

Keywords

• adsorption isotherms
• adsorption kinetics
• chromium(vi)
• jute stick charcoal