Highly ordered SBA-16 with low nickel amount for enhanced adsorption of methylene blue

Abstract Highly ordered SBA/16 structure with low concentration of nickel (SBA/16-Ni) was developed. SBA/16-Ni showed body-centered cubic structure containing a spatial group lm3m with pore diameter ranging from 4.5 to 6.0 nm. The Ni 2+ ions were set to be on SBA/16 walls to prevent pore clogging. The proposed material was engineered to be an environmentally friendly material for removal of pollutants from the aqueous environments. It was tested as a methylene blue (MB) adsorbent and the results compared with maximum adsorption of SBA/16 and other materials described in the literature. Among them, SBA/16-Ni adsorbed the larger amount of dye. The insertion of Ni +2 ions onto the SBA/16 walls increased the specific surface area, which contributed to increase the interaction between SBA/16 and MB. The applicability of the experimental data to the mathematical models indicated that the adsorption for SBA/16-Ni is predominantly driven by chemisorption, which was demonstrated to bean endothermic process. At room temperature, the value of ΔG° for SBA/16-Ni was shown to be more negative than that of SBA/16, suggesting an increase in the spontaneity of the adsorption. The presence of Ni 2+ ions on the material provided a structural environment more favorable for dye molecules being deposited. This idea was strengthened by the more negative ΔS° value of SBA/16-Ni. The Ni 2+ ions corrected somewhat structural imperfections on the material surface, creating regular and homogeneously distributed adsorption sites. SBA/16-Ni was shown to be a useful adsorbent with excellent performance for removal of pollutants.