Kinetics and Thermodynamics of Sorption of 4-Nitrophenol on Activated Kaolinitic Clay and Jatropha CurcasActivated Carbon from Aqueous Solution

Adsorption behaviour of 4-nitrophenol (4-NP) on activated kaolinitic clay and Jatropha curcasactivated carbon was investigated. The kaolinitic clay and Jatropha curcaswere activated with 1 M HNO3and 0.5 M NaOH respectively and were characterized byXRF, XRD, BET, SEM and FTIR techniques. The effects of processing parameters, such as initial 4-NP concentration, temperature, pH, contact time and adsorbent dosage on the adsorption process were investigated. The results obtained showed that Jatropha curcasactivated carbon exhibited higher performance than activated kaolinitic clay for the removal of 4-nitrophenol from aqueous solution. Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models were used to describe the adsorption isotherms. The adsorption data were best fitted with Freundlich model. The experimental data of the two adsorbate-adsorbent systems fitted very well with the pseudo-second order kinetic modelwith r2values of 0.999 respectively. Adsorption thermodynamic parameters were also estimated. The results revealed that the adsorption of 4-nitrophenol onto both adsorbents were exothermic processes and spontaneous for Jatropha curcasactivated carbon but non spontaneous for activated kaolinitic clay.