Equilibrium Adsorption Studies of Some Aromatic Pollutants from Dilute Aqueous Solutions on Activated Carbon at Different Temperatures (original) (raw)

1997, Journal of Colloid and Interface Science

variables on the equilibrium amount of adsorption is not Aqueous solutions of phenol, p-chlorophenol, and p-nitrophenol extensively studied. In order to effectively design activated have been used to determine the adsorption isotherm for single carbon adsorption units and to develop mathematical models solute systems on activated carbon at different temperatures. The that can accurately describe their operation, information on experimental program has been conducted to investigate the inboth the adsorption and the desorption of individual pollutfluence of concentration and temperature. All the reported equilibants under different operating conditions is required. rium isotherm equations have been tried on present and published Extensive experimental and modeling studies have been experimental data. A generalized isotherm equation which was reported to date on the activated carbon adsorption of a broad proposed by Khan et al. (6, 10) and tested for bi-solute adsorption spectrum of hazardous compounds from aqueous solution (1, data has been modified for single-solute system. The temperature 2). Yenkie and Natarajan (3) have reported the adsorption of dependency has also been incorporated into a generalized equation. It has been noticed that the Radke and Prausnitz (7) and general-some organic compounds (phenol, aniline, o-cresol, benzoic ized isotherm equations could represent the entire data with a miniacid, and p-methoxyphenol) at 35ЊC at six different adsormum average percentage error. The influence of different adsorbents. They could not represent the entire data by any of bents, sorbate concentrations, and pH of aqueous solutions has also the well-known isotherms. They have tabulated sections of been discussed in detail. The temperature dependency has been concentration range for which the Freundlich isotherm and investigated using both the Dubinin-Astakov (13) and the modified the Langmuir isotherm could represent experimental data generalized equation. The generalized equation describes the experisatisfactorily. Chatzopoulos et al. (4) have discussed the mental and published data adequately and provides a single value mechanism of adsorption and desorption on activated carbon of differential molar heat of adsorption, DH ads , for a single solute from aqueous medium. They have tried various types of adsorption system. The Dubinin-Astakov isotherm equation has empirical reported isotherms on their experimental data and shown an increasing trend of DH ads as the loading of adsorbent has found that the Fritz and Schlunder isotherm (5) could fit increased. ᭧ 1997 Academic Press their data at high concentrations and was, therefore, selected.