Bi-functional natural polymers for highly efficient adsorption and reduction of gold

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 422; p. 130577
• Main Authors: Li, Xue-Jing, Cui, Wei-Rong, Jiang, Wei, Yan, Run-Han, Liang, Ru-Ping, Qiu, Jian-Ding
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2021
• Subjects: Adsorption; Biomass material; Gold; Post-modification; Reduction; Gold; Biomass material; Reduction; Adsorption; Post-modification
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.130577

[Display omitted] •The synthesis of bi-function natural polymers is simple without expensive catalytic agents.•Bi-function natural polymers show superior selectivity and fast adsorption kinetics for recovery of gold.•Bi-function natural polymers act as the adsorbents for gold recovery through the synergistic mechanisms of adsorption and reduction.•The PDA-TFN-A exhibits outstanding Au(III) adsorption capacity up to 2771.8 mg/g at pH 2.0. Designing and synthesizing cost-effective and biodegradable adsorbents for recovering gold from electronic acidic waste have immense sustainable development significance. Herein, three natural macromolecules (polydopamine, chitosan and cellulose) as raw materials were selected to be chemically crosslinked with tetrafluoroterephthalonitrile (TFN) through aromatic nucleophilic reaction, respectively. Then cyano groups of the cross-linked products were converted into amides under alkaline conditions then gained PDA-TFN-A, Chitosan-TFN-A and Cellulose-TFN-A for specifically binding gold. The gold adsorption capacities were 2771.8, 2680.0 and 1992.0 mg g−1 for PDA-TFN-A, Chitosan-TFN-A and Cellulose-TFN-A, respectively. Moreover, various physicochemical and spectroscopic studies provided insight into the binding process, confirming the highly efficient adsorption and in-situ reduction of gold of bifunctional natural polymers based on the interaction of amide functional groups with Au and chloro gold complexes. In addition, the comparative analysis proved the optimum behavior of bi-functional natural polymer PDA-TFN-A with high capacity, selectivity, stability, and fast adsorption kinetics (15 min) for adsorption of gold. This work delineated a promising strategy for the application of eco-friendly natural polymers to solve environmental problems.