U(VI) removal by nanoscale zero-valent iron (nZVI) supported on raw and modified montmorillonite

RAMOS, C.P.; MARCO BROWN, J.L.; CANDAL, R.; VALIENTE, R.; TORRES SÁNCHEZ, R. M.

Ciudad Obregón, Sonora

Simposio; The Sixth International Symposium of Environmental Biotechnology and Engineering; 2018

Instituto Tecnológico de Sonora

The degradation of water environments by pollutants, both in surface and underground water bodies, is increasing, which makes access to drinking water a problem that is becoming increasingly difficult and expensive to solve. The study and development of systems capable of removing contaminants in solution, through systems based in cheap materials and low cost process, is considered as an alternative to conventional methods of water treatment. Water contamination by uranium is a problem of particular concern in Argentina due to its mining areas and nuclear power plants. Iron nanoparticles are propose as a relatively low cost alternative for the removal of U(VI) in water. In this work, a straightforward procedure based in the reduction of Fe3+ with NaBH4 method was used to synthesize nanoscale zero valent iron (nZVI) and nZVI supported in raw montmorillonite (MMT) and pillared MMT as materials for the removal of U(VI) in solution. The structural, textural and U(VI) removal properties of the synthesized materials were determined. Mössbauer spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) indicated that nZVI were obtained as aggregates of nanoparticles when they are not supported and as well dispersed nanoparticles when they are supported. The removal efficiency of U(VI) from water by a combination of adsorption and reduction/precipitation processes using materials synthesized was evaluated. U(VI) concentration, pH and oxidation-reduction potential (ORP) were measured during removal kinetics experiments. U(VI) removal using of nZVI supported on raw or pillared MMT proved to be more efficient than using non-supported nZVI. The removal of U(VI) turned out dependent on solution pH, being more favorable at acid pH. Supported nZVI are projected into the future as a suitable material for the development of U(VI) removal technologies.