Removal of nickel(II) ion from aqueous solution by adsorption on lightly calcined magnesia

Removal of nickel (II) ion from aqueous solution by adsorption on magnesia has been investigated. The influences of some factors, including solution pH value, stirring speed, adsorbent size, the amount of adsorbent, temperature and initial concentration of metal ion, on removal efficiency of nickel (II) ion and adsorption time have been studied. And then the surfaces of magnesia has been observed by using SEM method to find out the changes between before and after adsorbing ions. The results show that the adsorption process of nickel (II) ion on magnesia follows the first order kinetic model and at the initial nickel (II) ion concentration of 50 mg/L, more than 99% of the nickel (II) ion could be removed with the adsorbent concentration of 3 g/L. The results also show that the equilibrium isotherms of nickel adsorption onto magnesia coincide with Langmuir models. The adsorption capacity calculated from Langmuir isotherm is 21 mg nickel (II) (.) g(-1) at 30degreesC for the particle size of 0.22 min similar to 0.28 mm of magnesia.