Adsorptive Removal of Cr3+ Metal Ions onto MgO and Silica-Embedded MgO Nanoparticles: “Comparative Study
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ABSTRACT Wastewater treatment is one of the global environmental challenges, as the population is increasing along with the industrial activity. Based on previous studies, it is believed that nanotechnology offers the possibility of removing heavy metals from wastewater, as some nanoparticles have special economical and vital removal properties toward waste molecules. In this study, the adsorptive removal of trivalent chromium in aqueous solutions is studied using commercial MgO nanoparticles and in-house prepared silica embedded MgO nanoparticles. Adsorption isotherms and adsorbent characterization are investigated. Isotherm studies showed that the best fit for both adsorbents is the BET model, which describes the multilayer adsorption theory. The adsorption capacity was higher for the silica embedded MgO, 106 mg/g compared to 69 mg/g for commercial MgO nanoparticles. The higher affinity of the second layer over the first layer in BET isotherms emphasizes that the interaction is stronger between the adsorbate and the adsorbed layer than the adsorbate and the adsorbent. The approximate cost analysis showed that silica based MgO are more cost effective than commercial MgO nanoparticles. Adsorption isotherms and FT-IR study of the virgin and spent nanoparticles confirmed the adsorption of Cr3+ metal ions onto MgO adsorbents.