A customized MOF-polymer composite for rapid gold extraction from water matrices

Abstract

With the fast-growing accumulation of electronic waste and rising demand for rare metals, it is compelling to develop technologies that can promotionally recover targeted metals, like gold, from waste, a process referred to as urban mining. Thus, there is increasing interest in the design of materials to achieve rapid, selective gold capture while maintaining high adsorption capacity, especially in complex aqueous-based matrices. Here, a highly porous metal-organic framework (MOF)–polymer composite, BUT-33–poly( para -phenylenediamine) (PpPD), is assessed for gold extraction from several matrices including river water, seawater, and leaching solutions from CPUs. BUT-33–PpPD exhibits a record-breaking extraction rate, with high Au 3+ removal efficiency (>99%) within seconds (less than 45 s), a competitive capacity (1600 mg/g), high selectivity, long-term stability, and recycling ability. Furthermore, the high porosity and redox adsorption mechanism were shown to be underlying reasons for the material’s excellent performance. Given the accumulation of recovered metallic gold nanoparticles inside, the material was also efficiently applied as a catalyst.

Ultrafast and highly selective gold recovery with high capture capacity from electronic waste by upconversion of a silsesquioxane-based hybrid luminescent aerogel

“…5A). 48 In contrast, the PXRD pattern of PCS-CZ-B-DCM adsorbed in the dark showed no peak for Au(0), indicating that the reduction of Au( iii ) to Au(0) by the PCS-CZ-B-DCM requires visible light irradiation. The PCSs@chitosan can still reduce Au( iii ) to Au(0) under dark conditions due to the redox reaction between the amino and hydroxyl groups in the PCSs@chitosan and Au( iii ).…”

A Thermally Regenerable Cationic MOF Adsorption Material for Sustainable and Selective Removal of Hexavalent Chromium from Water

“…On the one hand, the amounts of adsorption sites might increase with more polymer loading and the adsorption capacity might also increase. On the other hand, when the polymer loading continued increasing to more than 35.9%, the extra guest copolymer molecular might block the pores of MIL-53, and the amounts of exposed adsorption sites might be reduced, so the adsorption capacity started to decreased . The results showed that the composites stirred for 6 h before polymerization exhibited the optimal adsorption property, and its corresponding polymer loading amount was 35.9 wt %.…”

Rapid and Selective Gold Stripping from Electronic Waste with Yolk–Shell-Structured Ion-Imprinted Magnetic Mesoporous Nanorobots for Efficient Water Decontamination

“…Among them, adsorption has been recognized as a feasible and environmentally friendly strategy due to its easy operation, low cost, high efficiency, and green process . Recently, numerous novel gold adsorbents with high capacities have already been explored, such as metal–organic frameworks (MOFs), − porous organic polymers (such as covalent organic frameworks, porous aromatic frameworks, , porous organic polycarbene, and porous porphyrin polymer , ), functionalized silicas, polysaccharides, chelating resins, and modified fibers . Although these adsorbents were effective in capturing gold from electronic waste, their tedious synthetic procedures, high-cost precursors, poor selectivity, and slow kinetics of some of them impede their practical applications.…”