Removal of Crystal Violet from Water by Adsorbent Prepared from Turkish Coffee Residue

Abstract

Carbon prepared from Turkish coffee residue was used to remove crystal violet dye from aqueous solutions. The adsorbent was characterized by surface analyzer, infra red (IR) spectroscopy, Boehm titration and mass titration. Adsorption was studied as a function of pH, dye concentration and contact time. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to describe the kinetic data. The adsorption of crystal violet dye on prepared adsorbent followed pseudo second order kinetic model rather than pseudo first order kinetic model. The adsorption equilibrium data were analyzed using the Langmuir, Freundlich and Temkin isotherms model. The pH of the solution affects the adsorption capacity of the adsorbent. An increase in the adsorption capacity of the dye was observed with increase in pH. However, this was up to pH 6.5. The increase was insignificant from pH 6.5 to 10. The desorption experiments showed the possibility of regeneration of the adsorbent. Equilibrium was attained within 4 hour for 30 mg L-1 of dye concentration, while for 25 mg L-1 and 15 mg L-1 it was less than 4 hour.