A novel phosphonic acid functionalized poly(vinyl chloride) electrospun nanofiber for efficient adsorption of gold from aqueous solution

Separation of gold from wastewater is an efficient approach to recycle the noble metal resources. Polymer-based adsorbents are widely used in separation because they are inexpensive and modifiable. Herein, a novel phosphonic acid functionalized poly(vinyl chloride) (PVC-APA) nanofiber was fabricated by the functionalization and electrospinning of PVC. PVC-APA exhibited superior adsorption performance for Au with a maximum adsorption capacity of 336.36 mg/g. The adsorption behavior conformed to the pseudo-second-order kinetic model and Langmuir adsorption isotherm, which was a spontaneous and endothermic process. The adsorption affinity between PVC-APA and Au was very strong even under the interference of multiple ions. Moreover, the reusability of PVC-APA was also satisfying. Comprehensive characterizations and comparative experiments revealed that two hydroxyl oxygen atoms in the phosphonic acid group and one nitrogen atom in the amine group can act as a tridentate ligand to chelate with Au. The adsorbed Au(III) ions can be partially reduced to Au0 by amino groups through a redox reaction. This work broadens the application of PVC in the field of precious metal recovery. [Display omitted] •PVC-APA electrospun nanofiber was successfully prepared.•Phosphonic acid groups on PVC-APA greatly improved the adsorption capacity.•PVC-APA exhibited high adsorption selectivity to Au.•Tridentate chelation between the O/N atoms and Au was the main mechanism.