Facile fabrication of nitrate-activated magnesite wastes-derived porous adsorbents with abundant active sites for highly efficient phosphate removal

Activating adsorbents with abundant pores and active sites is key to achieving efficient removal of pollutants from wastewater. However, the activation of stable magnesite slag (MS) to synergistically enhance its porosity and active sites is challenging. Herein, modified magnesite slag (MMS) was prepared using a facile nitrate-activation process (NAP) from MS to enhance its porosity and active sites. After NAP treatment, the morphology of the MMS wastes became highly porous with abundant MgO active sites. The MMS exhibited an outstanding maximum adsorption capacity of 836.2 mg/g. The impact of pH, adsorption time and initial solution concentrations on the adsorption capacity of phosphate was investigated systematically. The results revealed that weak acidic solution was beneficial to phosphate adsorption of MMS. The phosphate adsorption mechanism on MMS was mainly attributed to chemisorption. Moreover, NAP may be an effective method to activate MS adsorbents for phosphate removal from wastewater