Inorganic-organic mesoporous hybrid segregators for selective and sensitive extraction of precious elements from urban mining

Abstract

This study aimed to develop a highly selective extraction protocol for gold (Au^III) ions from electronic urban waste (EUW) using simple, low-cost Inorganic-organic mesoporous hybrid segregators. The unique features of mesoporous hybrid segregator architectures are of particular to ensure effective adsorption system in terms of selective and sensitive recovery of Au^III ions from EUW. The segregator platform featured 3D micrometric, mesocage double-serrated plant-leaf-like γ-Al₂O₃ sheets with hierarchy surfaces containing tri-modal mesopores interiorly and uniformly arranged toothed edges of ~20-40 and ~15 nm groove width and depth at the exterior surfaces, respectively. Rational incorporation of actively organic chelates into hierarchical γ-Al₂O₃ sheet platforms leads to the production of a couple of selective segregators 1 and 2 (namely, SC1 and SC2) for Au^III ions at specific conditions by applying batch and fixed-bed columnar techniques. The mesocage SC segregators offer a selective extraction approach of Au^III ions from mixed element contents released from a computer motherboard (CMB). Our finding indicated that the textural and hierarchal features of the mesocage SC segregators played key roles in the selective adsorption/recovery of Au^III ions at pH 2-2.5 with high capacity (136-141 mg/g range) and effective reusability ≫10 consecutive cycles. In general, the developed SCs could be utilized as a real extractor of Au^III recovery from spent CMBs.

Keywords: Batch and fixed-bed columnar techniques; Electronic urban waste; Gold recovery; Mesoporous γ-Al(2)O(3), Extraction.