Synthesis and characterization of mercapto-modified graphene/multi-walled carbon nanotube aerogels and their adsorption of Au(III) from environmental samples

In this study, mercapto-modified graphene/multi-walled carbon nanotube aerogels were facilely constructed by using L-cysteine as a cross-linking agent and modifier. The effective adsorption behaviors of Au(III) from environmental samples by the aerogels were investigated. The aerogels were characterized, and many influencing factors, such as pH value, adsorbent dosage, and contact time, were optimized. The kinetic data followed the pseudo-second-order model, and the equilibrium data fitted well to the Freundlich isotherm model. The maximum adsorption capacity for Au(III) reached approximately 47 mg g −1 . Moreover, the Au(III) could be desorbed with 1 M HCl containing 4% thiourea and detected by inductively coupled plasma atomic emission spectroscopy. Finally, the aerogels were used in lake water, seawater, and soil samples for Au(III) adsorption with recovery rates from 87.0% to 102.8%. The results indicate that the developed aerogel is an excellent adsorbent for removing Au(III) from samples and has significant application prospects in environmental research.