A comprehensive study on the uptake of dyes, Cu(II) and radioactive 137Cs(I) by sonochemically synthesized strontium/yttrium tungstate and molybdate nanoparticles

Abstract

SrWO4, SrMoO4, Y2WO6 and Y2Mo3O12 nanoparticles has been synthesized via a facile sonochemical route. The samples obtained have been characterized using powder XRD and TEM. The surface area and surface charge of the nanoparticles have been determined from BET adsorption isotherm of N2 and zeta potential studies, respectively. Sorption characteristics of all the samples have been analyzed for cationic dye (Rhodamine B, Methylene blue), heavy metal Cu(II) ion and radioactive 137Cs(I) uptake. The effect of pH, concentration of dye and loading of sorbent on the process of adsorption has been analyzed. SrWO4 could be used for the selective removal of RhB from a mixture of RhB and MB dyes. The dye sorption process for all samples has been discussed using Langmuir and Freundlich models. Kinetic studies indicate that the adsorption behavior obey the pseudo second order rate law. The rate determining step has been elucidated from the Webber Morris and Boyd plots. Thermal regeneration of the dye loaded sorbents is easily possible and similar adsorption efficiency upto six consecutive cycles has been demonstrated. For the Cu(II)/Cs(I) loaded samples, pH variation leads to efficient regeneration of the sorbents. A comparative study on the uptake properties of all four sorbents for dyes and toxic heavy metal ions indicates that the efficiency of the sorption process depends on the surface charge as well the inherent crystal structures of the materials. It could be inferred that sonochemically synthesized Y2Mo3O12 nanoparticles exhibits superior sorption characteristics for uptake of dyes, heavy-metal ions like Cu(II) and radioactive 137Cs(I) ions.