Chromium (III) adsorption from the phosphoric acid medium using DETA grafted Merrifield resin

To selectively remove Cr (III) from synthetic phosphoric acid solution, a chelating ion exchanger was developed through Merrifield resin (MHL) functionalization with diethylenetriamine (DETA). The functional moieties of the grafted Merrifield resin were characterized and confirmed by means of Fourier-transform infrared spectroscopy. The morphological changes before and right after functionalization were visualized with Scanning electron microscopy and enhanced amine content was confirmed via energy dispersive X-ray. To assess the effectiveness of the MHL-DETA in the extraction of Cr (III) from a synthetic phosphoric acid solution, batch shaking adsorption tests were conducted through optimizing different factors such as contact time, metal ion concentration and temperature. According to our findings, higher adsorption was achieved when increasing contact time and decreasing metal ion concentration, while temperature variation doesn't affect much the process. The higher sorption yield was found to be 95.88% attained within 120 min at room temperature without varying the solution's pH. Under optimum conditions (120 min, 25 °C and 300 mg. L^-1), the total sorption capacity was reported to be 38.35 mg. g^-1. The system's adsorption behavior was found to be consistent with the Langmuir isotherm and the pseudo second-order model accurately described the kinetic data. In this view, Merrifield resin functionalized with DETA could be used as a promising adsorbent material for Cr (III) adsorption from synthetic phosphoric acid medium.