Dual-Crosslinking Polydopamine/Poly(imide dioxime) Porous Network Membrane Enables Efficient and Selective Gold Recovery from e-Waste

With the sharp increase in electronic and electrical equipment as well as concomitant electronic waste, it is imperative to recover precious metals from secondary resources from the perspective of environment protection and sustainable development. Herein, a free-standing, dual-cross-linking polydopamine (PDA) in conjunction with poly(imide dioxime) (PIDO) porous membrane (denoted as PDA/PIDO) is fabricated via a facile interfacial polymerization method for gold recovery. As expected, the constructed PDA/PIDO membrane features a hierarchical porous structure, ample active sites, and excellent hydrophilicity, endowing it with an ultrahigh gold capture capacity (3368 mg g^–1), fast equilibrium time (35 min), superior recovery selectivity (separation factor of Au/Cu = 5.4 × 10⁵, Au/Ni = 3.9 × 10⁵), high flux (1050 L m² h^–1), and high retention rate (98%). Furthermore, the proposed PDA/PIDO membrane is also competent for selective gold recovery from the central processing unit leachate with remarkable efficiency in a continuous-flowing filtration system, highlighting its huge potential in practical large-scale gold recovery from e-waste.