Fast and high adsorption of Ni(II) on vermiculite-based nanoscale hydrated zirconium oxides

Novel vermiculite-based hydrated zirconium oxide (ZrO(OH)(2)/VMT) nanocomposites were synthesized via a simple ion exchange-precipitation method and applied to remove Ni(II) from aqueous solution. After ZrO(OH)(2) particles in the size range of 5-20 nm were loaded in the vermiculite (VMT), the prepared ZrO(OH)(2)/VMT had a lamellar structure with a high specific surface area of 130.86m(2)/g. The ZrO(OH)(2)/VMT adsorbent exhibited excellent stability in acidic solution. Adsorption equilibrium of Ni(II) was reached within 120 min, and the maximum Ni(II) adsorption capacity on ZrO(OH)(2)/VMT was 90.21 mg/g according to the Langmuir fitting, higher than most of the reported adsorbents. The adsorbed amounts of Ni(II) on the ZrO(OH)(2)/VMT increased with increasing solution pH from 2 to 8. The real electroplating wastewaters was employed to evaluate the adsorption of Ni(II) on the ZrO(OH)(2)/VMT in the column experiments, and about 402 bed volumes of waste-water could be treated before the concentrations of Ni(II) in effluent reached 0.1 mg/L. In addition, the spent ZrO(OH) 2/VMT could be successfully regenerated in 0.04 mol/L HCl solution, and the ZrO(OH)(2)/VMT exhibited stable adsorption for Ni(II) in the five successive adsorption cycles.