Chemically functionalized activated carbon with 8-hydroxyquinoline using aryldiazonium salts/diazotization route: Green chemistry synthesis for oxins-carbon chelators

Abstract

The past few years witnessed the emergence of aryldiazonium salts as versatile coupling agents for the functionalization of carbon and other substrates. Although the approach has demonstrated extensive applications in many fields, its use for the synthesis of chelating resins has not been explored. In this work, the concept has been exploited to develop an ecofriendly synthetic method for carbon based chelators. Herein, the p-nitroanline aryldiazonium salt was generated (in situ) in presence of hypophosphorous acid and covalently grafted onto activated carbon (AC) to allow addition of 8-hydroxyquinoline (8-HQ) via diazo coupling. The successfulness of the functionalization was confirmed by DRIR, XPS, and TGA. The risen was packed into cartridges and used with standard solid phase extraction (SPE) apparatus for the extraction of trace metals; Cd(II), Ni(II), Mn(II), Zn(II) and Pb(II) from groundwater samples prior to their measurement by ICPMS. The resin exhibited more 50% enhancement in capacity exchange relative to the plain AC. Under the optimum conditions the sorption capacity of the sorbent was 0.393, 0.170, 0.345, 0.092, 0.314 mmol g−1 for Mn(II), Cd(II), Ni(II), Pb(II) and Zn(II) respectively. The sorbent showed efficient performance when applied for SPE of trace metals from groundwater certified reference materials BCR-609 and groundwater real samples from AlMadinah AlMumnawarah, Saudi Arabia.