Mo (IV) adsorption from nitric acid media by Di-(2-ethylhexyl) phosphoric acid (D2EHPA) coated silanized magnetite nanoparticles

Di-(2-ethylhexyl) phosphoric acid coated silanized magnetite nanoparticles were applied for the rapid removal and fast adsorption of molybdenum ions from simulated nitric acid solutions. The characterization of the developed adsorbent was carried out using various analytical techniques such as Transmission electron microscopy (TEM), X-ray diffraction pattern (XRD) and Fourier transform infrared spectroscopy (FT-IR). The Transmission electron microscopy photographs showed that the silanized magnetite nanoparticles were roughly spherical in shape and the average size of these particles is very close to the average size of bare magnetite particles. The binding of silane polymer and Di-(2-ethylhexyl) phosphoric acid on the magnetite nanoparticles was confirmed through Fourier transform infrared spectroscopy. From the optimized influential parameters, it was found that as the acid (HNO3) concentration increases, the effect of this element vanishes and at concentrations above 1 M, this element has practically no influence on molybdenum adsorption. Regarding the effect of these elements on the process, the maximum K-d is obtained in a 0.75 M nitric acid solution which is 2780 mL/g. While on the other hand the increase in initial NH3 concentration decreases the desorption K-d values. The studies on the adsorption of Mo (IV) ions revealed that maximum adsorption efficiency was achieved with 0.5 M nitric acid. Also the adsorption of Mo (IV) from a solution containing Al, Ce, Cu, Fe, Ca and Si revealed that maximum adsorption efficiency was achieved in 0.75 M nitric add. Finally the Mo (IV) ion loaded particles were desorbed with NH3 as desorption agent. (c) 2016 Elsevier B.V. All rights reserved.