Efficient removal of Cr(VI) using recycled MgO from laterite nickel ore by fly ash doping

Environmental problems caused by Cr(VI) need to be solved urgently. As a green and safe adsorbent, magnesium oxide has the characteristics of strong adsorption capacity and safety, non-toxic and harmless. In this study, high-performance Cr(VI) adsorption material (F-MgO) was prepared by combination hydrothermal modification of recycling MgO and doping of solid waste fly ash with the MgO that was a by-product of high magnesium laterite nickel ore. The adsorption properties of F MgO composites for Cr(VI) were evaluated, and the maximum adsorption capacity of Cr(VI) by F MgO reaches 172.6 mg/g at pH = 2.0. The F-MgO also showed high stability and excellent cycle adsorption performance. The adsorption mechanism was extensively studied by adsorption kinetics and DFT theoretical calculation, and electrostatic adsorption and chemical interaction between Cr(VI) and F MgO active sites were demonstrated. The prepared F MgO composites from waste resources with a simple synthetic method have great potential in the treatment of chrome-containing wastewater to achieve the purpose of treating waste with waste.