A Facile Sol-gel Synthesis and Characterization of MgCO3/MnCO3 and MgMn2O4/Mn2O3 Novel Nanostructures With Remarkably High Adsorption Activity Toward Eriochrome Black T Dye

Exposure to high concentrations of the Eriochrome Black T dye causes some diseases such as skin infections, cancer, and blindness. Hence, in this paper, MgCO 3 /MnCO 3 (Abbreviated as MC) and MgMn 2 O 4 /Mn 2 O 3 (Abbreviated as MO) novel nanostructures were facilely synthesized using the precipitation and ignition methods, respectively. The produced Mg/Mn nanostructures were used for the effective removal of Eriochrome Black T dye from aqueous solutions. Therefore, the novelty in our current work comes from the use of a simple, easy, and inexpensive method to synthesize novel and effective novel nanostructures for the efficient removal of Eriochrome Black T dye compared to many other adsorbents in the literature. The high efficiency of the synthesized nanostructures is due to their small crystallite size and large surface area, which makes their adsorption property high. The XRD confirmed that the mean crystal size of the MC and MO products is 80.36 and 88.75 nm, respectively. The FE-SEM revealed that the MC product includes quasi-spherical shapes where their mean diameter equals 0.53 μm. Besides, the MO product includes quasi-spherical shapes where their mean diameter equals 0.25 μm, polyhedral shapes where their mean diameter equals 0.43 μm, and rectangular rods where their mean diameter equals 0.35 μm width and 4.63 μm length. The HR-TEM revealed that the MC product includes quasi-spherical shapes where their mean diameter equals 0.62 μm. Besides, the MO product includes polyhedral shapes where their mean diameter equals 0.41 μm and rectangular rods where their mean diameter equals 0.15 μm width and 0.45 μm length. The BET surface area of the MC and MO products is 66.47 and 60.23 m 2 /g, respectively. Furthermore, the maximum uptake capabilities of the MC and MO products toward Eriochrome Black T dye are 416.67 and 386.10 mg/g, respectively. Besides, the adsorption of the Eriochrome Black T dye using the MC and MO products is better described by the pseudo-first-order model and Langmuir isotherm. Additionally, the use of the MC and MO products to remove the Eriochrome Black T dye is an exothermic and physical process.