A comparative study of the removal of trivalent chromium from aqueous solutions by bentonite and expanded perlite

Adsorption of hexavalent chromium ions from aqueous solution by graphene nanosheets: kinetic and thermodynamic studies

“…Various adsorbents have been used for removal of Cr (VI) ions like silica gel, polymers, carbon nanotubes, activated carbon, bentonite, fly ash, clays, zeolites, chitosan, peat moss, biosorbents, and food wastes. (Chakir et al 2002;Saleh and Gupta 2012). However, some of these adsorbents have low adsorption capacities or need long adsorption equilibrium times, while others may have difficulty for regeneration and reuse even though they have high adsorption capacity and fast adsorption equilibrium (Nakano et al 2001).…”

Adsorption kinetics, isotherms and thermodynamics of Cr(III) on graphene oxide

“…The conventional removal methods of heavy metals from water include chemical oxidation or reduction, chemical precipitation, ion exchange, membrane technology, filtration, electrochemical treatment and adsorption etc. [9][10][11]. Among these approaches, adsorption has been found to be superior to other techniques due to its low-cost, high efficiency and easy operation [12,13].…”

Comparison of the Thermodynamic Parameters Estimation for the Adsorption Process of the Metals from Liquid Phase on Activated Carbons

“…The majority of studies on the sorption kinetics have revealed a two-step behaviour of the adsorption systems (Brigatti et al, 2000;Csobán et al, 1998;Raji et al, 1998) with fast initial uptake and much slower gradual uptake afterwards, which might take days even months Csobán et al, 1998;Raji et al, 1998;Kumar et al, 2000;Ajmal et al, 2001;Lakatos et al, 2002;Chakir et al, 2002;Leist et al, 2000;Csobán & Joó, 1999). Some of the authors reported the optimum contact time of minutes (Kumar et al, 2000;Ajmal et al, 2001), whereas, at the other extreme, that of hundred hours (Brigatti et al, 2000;Lakatos et al, 2002) for equilibrium to be attained; and the average values reported for the heavy metal binding were of 1-5 hours (Csobán et al, 1998;Raji et al, 1998;Chakir et al, 2002;Leist et al, 2000;Csobán and Joó, 1999). It has been also stressed that adsorption thermodynamics is drastically affected by the equilibrium pH of the solutions.…”