Removal of europium by green tea mediated zero valent iron nanoparticles

Abstract

Europium is the rarest and one of the least abundant rare-earth elements in the world. There are many chemical methods for this extraction of europium, among them application of green synthesized nanomaterial zero-valent iron (nZVI) is a very propitious, inexpensive, and eco-friendly technique. The nZVI nanoparticle was synthesized using green tea extract and applied for the reductive extraction of europium [Eu (III)] from an aqueous solution. The presence of polyphenolic compounds in the green tea extract was used as a reducing agent for the efficient formation of stabilized GT-nZVI. The green synthesized GT-nZVI nanoparticle was characterized by XRD and FTIR techniques. The performance evaluation of GT-NZVI for Eu removal was carried out under batch experiments with various experimental conditions such as, change in pH, initial Eu concentration, reaction time, and temperature. Almost 83 % of Eu was removed at pH 5 while only 65 % at pH 4 at 100 mg/L of initial Eu concentrations. GT-nZVI also shows better removal efficiency at high temperatures. According to the Langmuir isotherm model, GT-nZVI nanoparticles showed an adsorption capacity of 217.39 mg/g. The green synthesized nanoparticles also have good reusability capacity up to 4 consecutive adsorption cycles.