Construction of hydrophilic triazine-based covalent organic framework aerogels for enhanced adsorption and photocatalytic degradation of Congo Red

Abstract

Designing functionalized covalent organic frameworks (COFs) aerogels with optimized mass-transfer properties is crucial for improving the photocatalytic water treatment. Herein, two triazine-based COF aerogels with distinct functional groups were synthesized via a rapid Schiff-base reaction. The aerogels with ultralight 3D networks enabled the fast mass transfer and improved the exposure of both adsorption and photocatalytic active sites. Benefiting from enhanced hydrogen-bonding interactions and stronger electrostatic attraction, the hydroxylated aerogel TTP-A showed a higher adsorption performance toward anionic Congo Red (CR) than the non-hydroxylated aerogel TCA-A, with a maximum capacity of 538.95 mg g⁻¹ at 298 K. Moreover, the TTP-A aerogel delivered a markedly enhanced visible-light degradation efficiency of 84% within 120 min, significantly higher than the corresponding powder sample (59%) and the TCA-A aerogel (6%). This study demonstrates that rational chemical structure design coupled with aerogel structure provides an effective strategy to boost the photocatalytic performance of COF-based materials for water remediation.