Topology engineering of COFs via localized 1D - 2D unit interconnection to facilitate interfacial electron transfer for efficient gold recovery from ewaste leachates

Sep 30, 2026

Upload by Logic

Developing cost-effective adsorbents for gold recovery from electronic waste (e-waste) is crucial. A dimensional engineering strategy fabricates covalent organic framework (COF) heterostructures with locally interconnected 2D and 1D units, generating extra electron-transport pathways that accelerate adsorptive redox reactions. The TpaIda-2DCOF architecture delivers 3601 mg g−1 static adsorption capacity for Au(III), and 6900 mg g−1 under ultrasonic assistance. A fixed-bed system processes 35 L leachate, yielding 23.98 karat gold via in situ reduction while keeping material cost below 10 CNY g−1, supported by stepwise single-electron reduction.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Introduction

Challenges in gold recovery from e-waste

Limitations of existing adsorbents

Rationale for COFs and electron-transport engineering

Dimensionality and transport mechanisms in COFs

Chemical Science EDGE ARTICLE Cite this: DOI: 10 .1039/d5sc05206h All publication charges for this article have been paid for by the Royal Society of Chemistry Received 13th July 2025 Accepted 6th November 2025 DOI: 10.1039/d5sc05206h[rsc.li/chemical-science](rsc.li/chemical-science) Topology engineering of COFs via localized 1D–2D unit interconnection to facilitate interfacial electron transfer for eﬃcient gold recovery from ewaste leachates Jiaxing Xiong,a Qi An,b Hao Xiang,a Yu Zhou,a Yuan Zhang,a WenJing Chen,a Boxian Ren,a Shixiong Wang,a Huiping Bai,*b Hong Guo *b and Xiangjun Yang *a Developing cost-eﬀective adsorbents for gold recovery from electronic waste (e-waste) is crucial. Here, wereport a dimensional engineering strategy to fabricate covalent organic framework (COF) heterostructures with locally interconnected dimensions, enabling highly eﬃcient host–guest recognition of Au(III) in ewaste leachates. The heterostructures feature local interconnections between 2D and 1D units, introducing additional electron transport pathways. This structural innovation optimizes the electron transport kinetics essential for adsorptive redox reactions. Experimental results demonstrate that the locally interconnected dimensional architecture of TpaIda-2DCOF achieves a static saturation adsorption capacity of 3601 mg g−1 for Au(III) among the highest reported, which reaches an unprecedented 6900 mg g−1 under ultrasonic assistance. A ﬁxed-bed system processes 35 L of e-waste leachate, yielding 23 . 98 karat gold via in situ reduction while retaining a material cost below 10 CNY g−1—establishing it as one of the most cost-eﬀective COF-based adsorbents reported to date. Theoretical calculations and spectral analyses reveal that the additional charge transport channels created by the heterostructure facilitate the directional conversion of Au(III) to Au(0) through a stepwise single-electron reduction mechanism, thus constructing a closed-loop process for gold capture and recovery. Introduction With rapid technological advancements and the shortening of product lifecycles, waste electrical and electronic equipment has emerged as an “urban mine” rich in recoverable gold resources.1–3 Meanwhile, the escalating demand for gold has made eﬃcient targeted recovery from secondary resources increasingly imperative. Although biomass, metal–organic frameworks, activated carbon, and other materials have been extensively explored for gold recovery,4–8 they commonly suﬀer from limitations such as modest adsorption capacity, sluggish kinetics, high synthesis costs, and suboptimal selectivity. A key challenge in most contemporary designs is that adsorbed gold species is partially present in the ionic state, a phenomenon that signi􀀁cantly ampli􀀁es the complexity of subsequent recovery processes. These limitations are primarily attributed to the insuﬃcient electron-donating capacity of redox-active sites within the adsorbent host and ineﬃcient electron transfer processes, which hinder the directional conversion of Au(III) to aSchool of Chemical Science and Technology, Yunnan University, Kunming, 650091, China bInternational Joint Research Center for Advanced Energy Materials of Yunnan Province, School of Materials and Energy, Yunnan University, Kunming 650091, China Au(0) . Additionally, the high synthesis costs of materials render them dependent on multiple cycles of regeneration to achieve economic viability. This twofold bottleneck motivates a critical scienti􀀁c question: can we design inexpensive materials with intrinsic electron-transport pathways to construct an integrated system for concurrent adsorption-enrichment and in situ reduction, thus achieving a capture and recovery closed-loop process? Covalent organic frameworks9–11 (COFs) emerge as ideal material candidates owing to their tunable functionalities, eﬃcient electron/ion mobility,12 and designable redox sites.13 However, despite the implementation of strate

FAQs

What dimensional engineering strategy is used in this work?

The study fabricates COF heterostructures with local interconnections between 2D and 1D units, creating additional electron transport pathways for improved Au(III) capture and conversion.

How effective is the locally interconnected COF for Au(III) adsorption?

TpaIda-2DCOF reaches a static saturation adsorption capacity of 3601 mg g−1 for Au(III), and achieves 6900 mg g−1 under ultrasonic assistance.

How is gold recovered from e-waste leachates in the reported system?

A fixed-bed system processes 35 L of e-waste leachate and yields 23.98 karat gold via in situ reduction while maintaining a material cost below 10 CNY g−1.

Sep 30, 2026

Upload by Logic