Selective detection and efficient recovery of Au(III) based on 1D sulfur-rich covalent organic framework

Rising gold demand calls for sustainable extraction methods that go beyond conventional mining-dependent hydrometallurgy and pyrometallurgy approaches, as these traditional methods are plagued by inefficiency, high costs, and significant environmental risks. Adsorption-based methods using materials such as activated carbon or metal-organic frameworks have emerged as alternatives but face limitations in selectivity, stability, and mass transfer efficiency. This study introduces a sulfur- and nitrogen-functionalized 1D covalent organic framework (COF) with a 4-c sql topology, designed to overcome these challenges. Unlike 2D/3D COFs, the 1D structure minimizes interlayer stacking and enhances active site exposure, enabling rapid Au(III) detection (via fluorescence/colorimetric dual sensing) and in situ reduction to Au(0) without external reductants. Leveraging Au–S/N bonds and H-bonding interactions, the material achieved a low detection limit (8.5 × 10⁻⁹ M) and high adsorption efficiency in real-world scenarios, including river water and computer CPU leachates. The 1D COF's unidirectional electron channels and sulfur-rich moieties further improved selectivity and kinetics. This work demonstrates a dual-function platform for gold detection and recovery, offering a sustainable solution to mitigate e-waste hazards while advancing resource circularity. The findings highlight the potential of structurally engineered 1D COFs in precision metal recycling and environmental remediation.