No abstract

The retention of a pharmaceutical compound, Tiemoniummethylsulfate (TIM), from aqueous solutions by adsorption onto activated carbon prepared from date stones (AC-DS) was investigated. Physical and chemical characteristics of this material were also determined. Results showed that pH 8 was optimal for TIM adsorption. Among the kinetic models considered, the pseudo-second order model was the most appropriate to describe experimental data. Regarding adsorption isotherms, it was shown that the Sips model accurately describe the sorption of TIM onto AC-DS with a correlation factor R 2 > 0.98. The adsorption capacity of (AC-DS) was found to be 42.2mg g 1 at 10°C and 60.5mg g 1 at 25°C, confirming its efficiency for the removal of this compound from aqueous solutions. The values of ΔG 0 and ΔH 0 confirmed that the adsorption of TIM onto AC-DS was spontaneous and endothermic in nature, and hence more effective at high temperatures. An irregular increase in the randomness was suggested at the AC-DS-solution interface during the adsorption process for positive values of ΔS 0 .