Adsorptive removal of cesium using bio fuel extraction microalgal waste

Abstract An adsorption gel was prepared from microalgal waste after extracting biodiesel oil by a simple chemical treatment of crosslinking using concentrated sulfuric acid. The adsorbent exhibited notably high selectivity and adsorption capacity towards Cs + over Na + from aqueous solutions, within the pH range of slightly acidic to neutral. The adsorption followed Langmuir isotherm and the maximum adsorption capacity of the gel for Cs + calculated from Langmuir model was found to be 1.36 mol kg −1 . Trace concentration of Cs + ions present in aqueous streams was successfully separated from Na + ions using a column packed with the adsorbent at pH 6.5. The adsorption capacity of the gel towards Cs + in column operation was 0.13 mol kg −1 . Although the adsorbed Cs + ions were easily eluted using 1 M hydrochloric acid solution, simple incineration is proposed as an alternative for the treatment of adsorbent loaded with radioactive Cs + ions due to the combustible characteristics of this adsorbent.