Abstract
In this study, Jatropha seed shells from Yemeni plant have been tested for studying adsorption of treated seeds shells to remove chlorophenol compounds. The resulting adsorbents were designated as JAT1, JAT2 and JAT3. Most of the acidic groups on the surface were found to be phenolic in nature (37.5% in the case of JAT1 and 60% in the case of JAT). The adsorption of chlorophenol on JAT1, JAT2 and JAT3 was investigated in the temperature range 35–70 °C for initial chlorophenols concentrations ranging from 20 to 100 ppm. JAT2 was thereby found to be the best with respect to its capability to remove chlorophenols from solution indicating that thermal treatment at 500 °C is suitable to produce a good adsorbent. JAT3 is the worst in removing DCP even at high temperatures. It was also found that the removal efficiencies were in general enhanced at lower pH for all three adsorbents and for the two chlorophenols. For DCP, the corresponding heats of adsorption were found to be + 5.3, − 10.75 and − 14.4 kJ/mol. The small values for the heat of adsorption indicate that the interaction of chlorophenols with the adsorbent surface does not differ significantly from its interaction with water molecules in solution.