Sorption Properties of a Bentonite Based Material for Removal of Uranium from Alum Shale Leachate

Abstract

A dynamic sorption experiment was performed for removal of uranium (VI or 6+) from a leachate from an alum shale landfill with a diatomite-bentonite based sorbent in a laboratory scale. Such material was grounded and treated chemically with H3PO4 (phosphoric acid) and thermally for improving its porosity and resistance to water flow. A specific surface area of 209 m2 ·g-1 was determined by the BET method. A sorption capacity of 30 µg·g-1 and 0.6 µg·g-1 was obtained at a pH of 7.5 and 4 respectively by means of Langmuir and Freundlich isotherm models. The flow rate of 3 mL·min-1 was effective for controlling the pH inside of the column. The sorption mechanism was investigated along with desorption of the element of interest for further process design considerations for a treatment unit on the landfill site.