Efficient removal of methylene blue dye from aqueous media using Fe/Si, Cr/Si, Ni/Si, and Zn/Si amorphous novel adsorbents

In this paper, non-crystalline novel adsorbents composed of sodium, oxygen, silicon, and other metals such as iron, nickel, chromium, or zinc were produced using the gelation method. The amorphous products were characterized using various instruments, for example, XRD, FT-IR, FE-SEM, EDS, and BET. The BET affirmed that the amorphous products contain mesopores, micropores, and macropores. Broad XRD peak in the range 20 = 20-40 was gotten for every one of the synthesized products. Thus, the synthesized products were non-crystalline. The FE-SEM images showed that every one of the synthesized products consists of irregular shapes. FT-IR confirmed the presence of T O T bending, T O T symmetric, and T-O-T asymmetric vibrations (T = Si, M) (M = Fe, Ni, Cr, or Zn). Also, methylene blue dye was proficiently removed from aqueous media utilizing the amorphous products. Besides, the removal of methylene blue dye from aqueous media was assessed via studying some variables, for example, the concentration of dye, time, adsorption pH, temperature of dye solution, and reusability of amorphous products. In addition, the removal processes were physical, exothermic, spontaneous, and follow both of the pseudo-first-order kinetic model and Freundlich isotherm. Moreover, the amorphous products have adsorption capacity values in the range from 36.51 to 53.79 mg/g. Finally, the amorphous products were regenerated then reused without changing their efficiency. (C) 2019 The Authors. Published by Elsevier B.V.