Magnetic Prussian Blue derivative: An efficient material for thallium removal from simulated mining wastewater

Y.C. López, G.A. Ortega, M.A. Martínez, E. Reguera
Instituto Politécnico Nacional,
Mexico

Keywords: magnetite nanoparticles, metal hexacyanoferrates, thallium(I) magnetic removal

Summary:

Thallium(I) is one of the most toxic metal ions known as the poisoner’s poison. Environmental thallium concentration has been increasing due to anthropogenic events while a negligible approach to Tl removal studies is reported. This research, proposes a new composite (ZnKFeCN@Fe3O4) for thallium(I) removal. The obtained magnetic composite was characterized (FTIR-ATR, TGA, XRD, TEM/SEM, XPS, BET, Magnetization). The capacity of the new composite for Tl removal from simulated wastewater was evaluated as well as the influence of different experimental conditions. The maximum sorption capacity was 120 mg of Tl(I) per gram of composite after 24 hours of interaction, and removal by means of magnet achieving a final Tl concentration 28 times lower than the permitted limit for wastewaters. The removal process is independent of the pH with slight interferences of typical ions contained in wastewaters of the mining industry. The sorbent is reusable with non-significative variations of the thallium sorption capacity (5 % loss of removal capacity after 6 cycles), allowing to recover 97 % of removed thallium under KCl solution desorption treatment. The main mechanism involved in the separation of Tl(I) is a K-Tl ionic exchange described by a pseudo-second-order and intra-particle diffusion kinetics. Herein, a new sorbent material easy to prepare, low-cost, reusable and eco-friendly is presented for effective magnetic thallium removal from wastewaters.