Novel wood membrane decorated with covalent organic frameworks and palladium nanoparticles for reduction of aromatic organic contaminants

Abstract

With the development of industry, environmental pollution has become increasingly serious. The removal of contaminants from wastewater remains an important challenge for environmental remediation. However, many nanomaterials with excellent properties are in powder form, which limits their practical application. To overcome these issues, we have developed a three-dimensional (3D) wood membrane (Pd@COF/wood) decorated with covalent organic frameworks (COFs) and palladium nanoparticles (Pd NPs) for the effective removal of aromatic organic pollutants. The COF with a large specific surface area can be used as support for immobilizing Pd NPs to improve catalytic activity. Benefiting from the elongated and partially aligned channels along the direction of the wood growth, the Pd@COF/wood displays superior catalytical efficiency for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB) with the reaction rate constants of 0.72 and 0.85 min−1, respectively. As the filter membrane, the MB degradation efficiency of the Pd@COF/wood membrane reaches over 98 % with a permeance of 1.57 × 104 L·m−2·h−1·bar−1. Meanwhile, the resulting Pd@COF/wood possesses exceptional recyclability and oil–water separation ability. We believe that the Pd@COF/wood is of great significance for environmental remediation, and the synthetic strategy is applicable to establish more multifunctional hybrid nanomaterials, which derive from other COFs and NPs for catalysis.