Rapid removal of thallium from water by a new magnetic nano-composite using graphene oxide for efficient separation

Abstract

Thallium contamination has raised global concern due to its high toxicity and treatment difficulties. In this study, the magnetic adsorbent rGO-Fe3O4@TiO2 was synthesized for the effective removal of thallium(I) from water. The stable magnetism of the adsorbent before and after the adsorption ensured the facile magnetic separation from treated streams. The abundant hydroxyl groups on the surface of nano-sized TiO2 particles served as adsorptive sites for the Tl(I) ions. The adsorbent performed a fast adsorption rate of Tl(I), achieving approximately 50% of ultimate adsorbed amount within the initial 10 min at near neutral condition (pH 7.0). Tl(I) removal was significantly enhanced by increasing solution pH value due to the electrostatic attraction between Tl(I) ions and the adsorbent surface. Isotherm study showed that the adsorption process was favorable, with the maximum adsorption capacity of 141.8 mg g−1. The presence of co-existing cations might interfere and compete with the adsorption sites of Tl(I) ions. The prepared magnetically responsive adsorbent with good regeneration ability could be used as a competitive alternative to address the sudden thallium pollution incidents considering its rapid rate and high efficiency for Tl(I) adsorption and removal from aqueous systems.