Three-dimensional self-assembled reduced graphene oxide composite as a promising adsorbent for the collection of palladium (II) and platinum (IV) in a low concentration

A three-dimensional reduced graphene oxide aerogel modified by sulfamic acid and ethylenediamine was prepared via one-step reduction self-assembly under atmospheric pressure within 90 °C heating constantly. The adsorption efficiency of palladium (II) was ~ 97.0% at pH 11 within 50 min by the prepared composite. While the composite exhibited adsorption for platinum (IV) at acid condition, giving a rising to an adsorption efficiency was 61.7% at pH 5. Only 25.8% adsorption efficiency of platinum (IV) was found at pH 11, and 17.0% adsorption efficiency of palladium (II) was obtained at pH 5. The adsorption capacity of the composite for palladium (II) was 80 μg mg−1 above, and the adsorption capacity of the composite for platinum (IV) was ~ 160 μg mg−1. The obtained palladium (II) and platinum (IV) can be eluted by urea and surfactant from the surface of the composite, respectively. Understanding the mechanism of the adsorption/desorption between palladium (II)/platinum (IV) and the composite, explored a promising way for recycling and enrichment of noble metal at a low concentration.