Preconcentration and Determination of Nickel ions using Silica with Functional Groups of Sulfonic Derivatives of Nitroso Naphthols

Abstract

Silica based adsorbents modified with polyhexamethylene guanidine and sulfonic derivatives of nitroso naphthols - nitroso-N salt (NNS) and nitroso-R salt (NRS), have been proposed for preconcentration and solid-phase photometric determination of Ni(II) in industrial solutions. Adsorbents with the surface concentration of the reagents of 1.5 and 3 μmol/g have been studied. Adsorbents with NNS functional groups quantitatively extract Ni(II) at pH 5.5-7.5, while with NRS functional groups – at pH 5.5-7.0, giving complex compounds with the composition Ni(II) : Reagent = 1 : 3. After Ni(II) adsorption the adsorbents became orange (λ = 510 нм) or brown (λ = 490 нм) for NNS and NRS respectively. The pH range of maximum color intensity coincides with the pH range of the quantitative extraction of Ni(II). The procedure of solid-phase photometric determination of Ni(II) in form of diffuse reflectance spectroscopy has been developed. The analytical range of the procedure is 0.1 – 3.0 μg of Ni(II) per 0.1 g of the adsorbent with the surface concentration of the reagent of 1.5 μmol/g and 0.15 – 6 μg of Ni(II) per 0.1g of the adsorbent with the surface concentration of the reagent of 3 μmol/g. The procedure was used for determination of Ni(II) in the rinsing and waste waters of galvanic manufactory. The results accuracy was confirmed by ICP-OES analysis.