Single-factor experiments were carried out to investigate the effects of Magnesium hydroxide dosage, pH, temperature and adsorption time on the adsorption of Magnesium hydroxide. The thermodynamic and kinetic characteristics of arsenic adsorption on Magnesium hydroxide were studied, and the mechanism was discussed.
The results showed that the adsorption of arsenic was stable at the initial concentration of 0.5-100 mg/l, temperature of 25 ° C, pH of 3, Magnesium hydroxide dosage of 0.5-4 g and adsorption time of 1 H, the removal rate of arsenic ion can reach more than 99% by Magnesium hydroxide. Under the same conditions, the equilibrium time of As (III) adsorption by Magnesium hydroxide was 80 min. The Sorption isotherm fit the Freundlich model, the double-constant model and the parabola kinetic equation, which were used to characterize the adsorption kinetics of As (III) on the Magnesium hydroxide. The adsorption free energy △ Go was negative, indicating that the Magnesium hydroxide adsorption of arsenic ions was spontaneous.