Optimizing U(VI) Adsorption onto Microwave Activated Rice Husk Ash through Response Surface Methodology

Response surface methodology combined with Box-Behnken experimental design were employed to study the adsorption of U(VI) on microwave activated rice husk ash (ARHA) to elucidate the effects of parameters such as pH, adsorbent dose and U(VI) initial concentration on the adsorption process. Experimental data indicated that pH and adsorbent dose positively affected the adsorption process of U(VI) by ARHA, however, this effect was partially offset by the effect of the initial concentration. The highest adsorption percentage for U(VI) observed at pH of 6.14, adsorbent dose of 0.478 g and U(VI) initial concentration of 38.93 mg/l. With five cycles desorption/adsorption without changing the adsorption efficiency, it could be concluded that ARHA is a promising adsorbent for uranium removal.