Nickel/nickel boride nanoparticles coated resin: A novel adsorbent for arsenic(III) and arsenic(V) removal

A novel adsorbent named nickel/nickel boride nanoparticles coated resin has been introduced for the removal of both As(III) and As(V) from water. Nickel/nickel boride nanoparticles were formed on Purolite C-100 resin successfully. Perlite, pumice, zeolite and silica gel were also tried as the support material. However, nickel/nickel boride nanoparticles on those materials were not stable. Optimal preparation conditions for nickel/nickel boride nanoparticles coated resin were established. In the batch method, initial pH did not significantly affect the arsenic removal efficiencies for As(III) and As (V) in the pH range 33-11.5. As(III) and As(V) were removed quantitatively from the solutions at all pHs. 15% and 10% decreases were observed for As (III) removal efficiency when the solution contained phosphate and silicate respectively. However, none of the ions studied showed significant effect on the As(V) removal efficiency. Isotherm studies indicate that the Langmuir model fits the experimental data better than the Freundlich model. The isotherms also showed that the adsorption is favorable. Maximum arsenic adsorption capacities were calculated as 23.4 mg/g and 17.8 mg/g for As(III) and As(V), respectively. The kinetics of the adsorption process were tested for the pseudo-first order and pseudo-second order and intra-particle diffusion models. The comparison among the models showed that the pseudo second-order model best described the adsorption kinetics. As(III) and As(V) could be desorbed from the adsorbent without any efficiency loose using a mixture containing NaCl and NaOH and, therefore, the adsorbent could be used several times. Ni/NixB-NPCR could reduce the concentration of both As(III) and As(V) below the maximum allowable concentration level (WHO limit, 10 mu g/L) from such high arsenic containing waters. (C) 2014 Elsevier B.V. All rights reserved.