Recycling of Pb2+ by in situ confined conversion of adsorbed Pb2+ to CsPbBr3 nanocrystals in thiol-functionalized COFs

In recent years, lead ion (Pb 2+ ) pollution control technologies have continued to advance. Among them, the adsorption method has shown promising application prospects. However, existing adsorption methods focus solely on Pb 2+ removal while neglecting the subsequent transformation and functionalization of the recovered Pb 2+ . To address these issues, thiol-functionalized covalent organic frameworks (COFs) were synthesized for recovery of Pb 2+ and confined conversion of Pb 2+ to CsPbBr 3 nanocrystals (NCs), an optoelectronic material. The effects of morphologies and surface chemistry of COFs on the adsorption efficiency for Pb 2+ were studied. The morphology tuning of COFs from spherical shape to flower shape with a myriad of humps on the surface boosted the adsorption efficiency for Pb 2+ from 25% to 85%. After thiol modification by 1,2-ethanedithiol, the adsorption efficiency of COFs for Pb 2+ increased by nearly 10-fold. The maximum adsorption capacity of thiol-functionalized COFs for Pb 2+ was 54.3 mg·g −1 . The adsorption isotherm was best described by the Langmuir model. Utilizing the mesopore-confined effect of COFs, the enriched Pb 2+ were converted into CsPbBr 3 NCs. The CsPbBr 3 NCs confined in COFs exhibited excellent stability and could generate singlet oxygen ( 1 O 2 ) under the irradiation by xenon lamp, revealing their potential applications in photocatalysis, bacteriostasis, light emitting diode and sensing. This work provides a prototype for both the removal and recycling of polluted Pb 2+ .