文摘
Graphene oxide (GO) was prepared and characterized by Fourier transform infrared spectrometry (FT-IR) and scanning electron micrographs (SEM). Batch adsorption studies were carried out to investigate the adsorption data, including the effects of pH, initial concentration, contact time, and temperature. The adsorption of Au(III), Pd(II), and Pt(IV) was optimum at pH 6.0. The adsorption isotherms all obeyed the Langmuir equation in the case of Au(III), Pd(II), and Pt(IV), and the maximum adsorption capacities were 108.342 mg路g鈥?, 80.775 mg路g鈥?, and 71.378 mg路g鈥?, respectively. The adsorption kinetics of Au(III), Pd(II), and Pt(IV) onto GO followed a pseudosecond-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. Thermodynamic parameters such as Gibbs energy (螖Go), enthalpy (螖Ho), and entropy (螖So) were calculated, indicating that the adsorption were spontaneous, endothermic, and feasible. The desorption studies showed that the best desorption reagents were 0.5 mol路dm鈥? thiourea鈥?.5 mol路dm鈥? HCl for Au(III) and 1.0 mol路dm鈥? thiourea鈥?.5 mol路dm鈥? HCl for both Pd(II) and Pt(IV).