Abstract
In this study, the potential of KOH-oxidized rice straw-based activated carbon for uranium adsorption from aqueous solution was studied. Effect of different parameters including contact time, initial uranium concentration; initial pH and temperature were studied. Uranium up take was fast and need a short time of 40 min. Adsorption isotherms were well fitted by Langmuir model (R-2 = 0.999) and Dubinin-Radushkevich (D-R) model (R-2 = 0.99) with activation energy values in the energy range of an ion-exchange reaction. A temperature was found to increase the adsorption of uranium from 100 mg/g to 127 mg/g when it was increased from 298K to 328K. Thermodynamic parameters including Delta H degrees, Delta S degrees, and Delta G degrees were calculated, which showed that uranium adsorption was spontaneous, exothermic nature and there is evident of decreasing metal ions randomness at the solid-liquid interface. Findings from the present study showed that potassium hydroxide-modified straw-based carbon can be successfully used for removal of uranium from aqueous solution.