Bi doping starch-DMAEMA hydrgel for efficient removal of Sr(II)

One of the most significant environmental issues currently facing humanity is heavy metal contamination. The purpose of this study is the removal of Strontium ions Sr(II) by using gamma radiation to create starch/poly[2-(dimethylamino) ethyl methacrylate]/bismuth (St/DMAEMA/Bi) hydrogel nanocomposite. On the removal of Sr(II) ions, the effects of pH, contact time, adsorbent dose, and temperature were examined. The experimental data were fitted by Freundlich and Langmuir isotherm models. The results proved that the Langmuir isothermal model describes the absorption process well. To describe the adsorption kinetics of Sr(II) ions in compounds, the pseudo-second-order kinetic model is suitable. The thermodynamic results (ΔG°, ΔS°, and ΔH°) and isotherm investigations support the endothermic nature of the adsorption of Sr(II) ions on St/DMAEMA/Bi hydrogel nanocomposite. Positive ∆H° values demonstrated the endothermic nature of the adsorption, while positive ∆S° values verified the increased randomness during the process, and the negative values of ΔG° show that the obtained experimental data best fits.