Removal of the heavy metal ion nickel (II) via an adsorption method using flower globular magnesium hydroxide

To remove toxic Ni(II) ions from wastewater, a novel flower globular magnesium hydroxide (FGMH) was prepared by a gentle method using trisodium citrate as a crystal modifier. This material exhibited a high specific surface area. The synthesized products and adsorption mechanism for Ni(II) ions were examined by diverse characterization technologies and methods. FGMH was employed to remove Ni(II) ions by the adsorption method. The effects of various parameters, viz., the amount of adsorbent, contact time, temperature and pH, on the removal rate by the adsorbent were investigated in detail. The kinetic data fitted well with a pseudo-second-order model and experimental equilibrium adsorption data conformed to a Langmuir isotherm under optimized conditions. The optimal process parameters included 30 mg of FGMH, a 50 min contact time, pH values between 6.07 and 7.71 for the Ni(II) solution, and adsorption at room temperature for 50 mL of 80 mg/L Ni(II) solution. The percentage of removal efficiency was found to be above 92.64%, and the maximum adsorption capacity of MH was 287.11 mg/g under optimum adsorption conditions. The analyses indicated that the Ni(II) ions were chemisorbed on the FGMH surface.