Construction of an acid-tolerant cationic COF by Zincke reaction for efficient recovery of gold from e-waste via anion exchange and chemical reduction
Recovering gold from electronic waste (e-waste) is critical for sustainable resource management, yet conventional adsorbents suffer from poor acid stability and slow kinetics. Here, we report an acid-resistant cationic covalent organic framework (COF), TAPT-TNV, synthesized via irreversible Zincke reaction. TAPT-TNV exhibits exceptional stability in concentrated acids, retaining crystallinity and porosity after exposure to 12 M HCl and 6 M HNO3. The cationic skeleton, balanced by Cl− counterions, enables rapid and selective capture of AuCl4− through anion exchange, complemented by chemical reduction at triazine units. Adsorption kinetics are fast, reaching equilibrium within 30 minutes, with a maximum capacity of 1835.5 mg g−1 at pH 1. In real e-waste leachate, TAPT-TNV achieves a gold recovery rate of 99.42%, demonstrating high selectivity over competing metal ions. This work introduces a robust COF platform for precious metal recovery, addressing the limitations of hydrolytically unstable frameworks.