Selective high capacity adsorption of Au(III) from aqueous solution by poly(glycidyl methacrylate) functionalized with 2,6-diaminopyridine

A new adsorbent was synthesized by functionalizing poly(glycidyl methacrylate) with 2,6-diaminopyridine for the selective adsorption of Au(III) from aqueous solution. The fourier transform infrared spectrometer, X-ray photoelectron spectroscopy and scanning electron microscope demonstrated that 2,6-diaminopyridine was successfully grafted onto poly(glycidyl methacrylate). The batch adsorption experiments were conducted to evaluate the adsorption abilities of the adsorbent. The results show that the adsorbent exhibits high adsorption capacity (459.29 mg/g) for Au(III) at pH 4. The adsorption process of Au(III) are well described by pseudo-second-order kinetic model. The adsorption isotherm is well-obeyed Langmuir and D–R models. The calculated thermodynamic parameters of the adsorption process are: ΔG⁰ = − 24.2 kJ/mol; ΔH⁰ = 37.0 kJ/mol; ΔS⁰ = 205.4 J/mol K. The adsorbent is interacted with Au(III) through chelation and ion exchange between the amines groups and Au(III). Moreover, the adsorbent shows good selectivity from the interfering ions and can be reused at least five times.