Adsorption of Cr(Ⅵ) polluted water by Fe(3)O(4)@SiO(2)-APTMS nanocomposites prepared in the presence of ultrasonic irradiation for sustainable water resources utilization

The research on developing a purification technology for Cr(Ⅵ) polluted water with high efficiency and the low energy consumption is crucial for achieving several Sustainable Development Goals (SDGs). In order to achieve these goals, Fe(3)O(4)@SiO(2)-APTMS nanocomposites were prepared by Fe(3)O(4) nanoparticles modified with silica and 3-aminopropyltrimethoxysilane in the presence of ultrasonic irradiation. The nanocomposites were characterized by TEM, FT-IR, VSM, TGA, BET, XRD, XPS and these analytic results proved that the nanocomposites were successfully prepared. The influential factors of Fe(3)O(4)@SiO(2)-APTMS on Cr(Ⅵ) adsorption have been explored and better experimental conditions have been obtained. The adsorption isotherm conformed to the Freundlich model. Pseudo-second-order kinetic model provided a better correlation for the experimental data compared to other kinetic models. Thermodynamic parameters for adsorption indicated that the adsorption of Cr(Ⅵ) was a spontaneous process. It was speculated that the adsorption mechanism of this adsorbent includes redox, electrostatic adsorption and physical adsorption. In summary, the Fe(3)O(4)@SiO(2)-APTMS nanocomposites were of great significance to human health and the remediation of heavy ion pollution, contributing to achievement of the Sustainable Development Goals (SDGs), including SDG-3, SDG-6.