ZIF-67-derived Co@N-PC anchored on tracheid skeleton from sawdust with micro/nano composite structures for boosted methylene blue degradation

Abstract

• ZIF-67-derived Co@N-PC catalyst with unique micro-nano porous structure was successfully prepared. • Co@N-PC shows boosted methylene blue degradation ability, magnetic recovery and decent reuse stability. • ZIF-67 could be uniformly grown in situ on the surface of tracheid skeleton in poplar sawdust. Metal-organic frameworks (MOFs) derived carbon based nanocatalysts have been widely used in the environmental field due to high porosity, rich structural diversity/adjustability, and controllable chemical compositions. However, a suitable carrier is very necessary for solving the issues of aggregation and recovery of nanoparticles. Here, waste biomass of sawdust with low cost, abundant resource and special lumen structure, has been used as scalable carrier for Co-MOFs (ZIF-67). Due to the coordination of Co ions with abundant oxygen-containing functional groups of wood, ZIF-67 could be uniformly grown in situ on the surface of poplar sawdust with tracheid skeleton, and a magnetic catalyst possessing micro-nano porous structure has been successfully prepared by further carbonization (Co@N-PC). The catalytic ability of Co@N-PC was studied by activating potassium peroxomonosulfate (PMS) to remove methylene blue (MB). The results indicate the degradation efficiency on MB of Co@N-PC can reach 100% within 30 min which shows excellent catalytic performance. The boosted MB degradation ability mainly results from its unique micro-nano porous structure facilitating efficient material transfer and electron transfer during degradation process. At the same time, a possible catalytic mechanism was proposed. Moreover, Co@N-PC can be easy to separate and reuse from the solution by an external magnet, and performed decent stability. This work not only provides a simple and effective strategy to design large-scale and commercially viable biomass/MOF derived catalysts for water treatment, but also offers a decent alternative for high value utilization of waste biomass.