Preconcentration And Determination Of Nickel Ions Using Silica With Functional Groups Of Sulfonic Derivatives Of Nitroso Naphthols

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.