Removal of phenols and chlorophenols from aquatic system using activated clinoptilolite

Phenols and chlorophenols are toxic to other organisms in aqueous media even at very low concentrations. Phenols are the most common pollutants in aqueous media. This study deals with the removal of phenols and chlorophenols from the aqueous media in a batch system by the use of activated clinoptilite. The equilibrium time of the adsorption of phenols and chlorophenols, the effect of the initial concentration upon the adsorption rate, the effect of the pH and the possibility of regeneration have been examined. The adsorption phenomenon of the phenols and chlorophenols on activated clinoptilite samples at different time ranges was investigated to elucidate the equilibrium times with increasing phenol and chlorophenol concentration. The amount of adsorption on to clinoptilite was observed to increase in the order of phenol, p-chlorophenol, o-chlorophenol and m-chlorophenol and the maximum adsorption equilibrium time was found to be approximately 45 minutes. Apart from those the possibility of regenerating the used clinoptilite samples with the use of 30 % (v/v) methanol solution.Zeta potential experiments were carried out in order to determine the behavior of clinoptilolite and it was observed to exhibit a negative charge. The adsorption studies carried out between 45oC and 65 oC suspension temperatures revealed that the adsorption values showed a decrease with the increasing temperature .The facts that adsorption yield has reached up to 99%, the adsorption heat was lower than 10 kcal / mol according to the adsorption method employed and the increase in the heat of suspension showed that phenols and its derivatives are adsorbed according to physical adsorption.The natural and the activated clinoptilolites were examined by the use of FTIR, SEM, EDX and DTA-TGA analysis techniques before and after the adsorption process. Also the effect of the initial phenol and chlorophenols concentration on the removal efficiency and the related adsorption isotherms was investigated. The removal efficiency of clinoptilolite was investigated according to phenol and chlorophenol concentrations and it was observed that clinoptilolite has a higher efficiency than that of natural clinoptilolite. The adsorption was observed to take place according to the Freundlich isotherm.Key Words: Clinoptilolite, Activation, Adsorption, Phenols.