Facile Synthesis and Characterization of Sodium Magnesium Silicate Hydrate/Sodium Magnesium Silicate Hydroxide as Novel Nanostructures for the Efficient Removal of Methylene Blue Dye from Aqueous Media

Methylene blue dye can cause damage to the eyes of humans and animals, as well as skin irritation. Also, it can result in nausea, cancer, vomiting, convulsions, and diarrhea. Consequently, in this work, an aqueous solution of sodium metasilicate pentahydrate (12 g dissolved in 50 mL of deionized water) reacted separately with two aqueous solutions of magnesium nitrate hexahydrate (8.47 g dissolved in 50 mL of deionized water and 11.47 g dissolved in 50 mL of deionized water) to obtain sodium magnesium silicate hydrate/sodium magnesium silicate hydroxide as novel nanostructures via the sol-gel method. Besides, the synthesized nanostructures were utilized for the efficient removal of methylene blue dye from aqueous media. The mean crystallite sizes of the nanostructures, which were synthesized using 8.47 and 11.47 g of magnesium nitrate hexahydrate, are 73.17 and 60.25 nm, respectively. The nanostructures, which were synthesized using 8.47 and 11.47 g of magnesium nitrate hexahydrate, were composed of cubes, spheres, and irregular shapes with mean grain sizes of 175 and 110 nm, respectively. The BET surface areas of the nanostructures, which were synthesized using 8.47 and 11.47 g of magnesium nitrate hexahydrate, are 171.04 and 189.90 m(2)/g, respectively. The maximum adsorption capacities of the nanostructures, which were synthesized using 8.47 and 11.47 g of magnesium nitrate hexahydrate, toward methylene blue dye are 384.62 and 404.86 mg/g, respectively. The adsorption of methylene blue dye using the synthesized nanostructures is consistent with the pseudo-second-order kinetic model and the Langmuir equilibrium isotherm. Also, the adsorption of the methylene blue dye is chemical and exothermic.

Automated summary

A novel nanostructure, synthesized using the sol-gel method, showed high adsorption capacity for methylene blue dye. The nanostructure was obtained by reacting an aqueous solution of sodium metasilicate pentahydrate with two different aqueous solutions of magnesium nitrate hexahydrate. The adsorption followed the pseudo-second-order kinetic model and the Langmuir equilibrium isotherm.