Gravity-driven rattan-based catalytic filter for rapid and highly efficient organic pollutant removal.

Metal organic frameworks hold great promise as heterogeneous catalysts in sulfate radical (SO4∙-) based advanced oxidation. However, the aggregation of powdered MOF crystals and the complicated recovery procedure largely hinder their large-scale practical applications. It is important to develop eco-friendly and adaptable substrate-immobilized metal organic frameworks. Based on the hierarchical pore structure of the rattan, gravity-driven metal organic frameworks loaded rattan-based catalytic filter was designed to degrade organic pollutants by activating PMS at high liquid fluxes. Inspired by the water transportation of rattan, ZIF-67 was in-situ grown uniformly on the rattan channels inner surface using the continuous flow method. The intrinsically aligned microchannels in the vascular bundles of rattan acted as reaction compartments for the immobilization and stabilization of ZIF-67. Furthermore, the rattan-based catalytic filter exhibited excellent gravity-driven catalytic activity (up to 100 % treatment efficiency for a water flux of 10173.6 L·m-2·h-1), recyclability, and stability of organic pollutant degradation. After ten cycles, the TOC removal of ZIF-67@rattan was 69.34 %, maintaining a stable mineralisation capacity for pollutants. The inhibitory effect of the micro-channel promoted the interaction between active groups and contaminants, increasing the degradation efficiency and improving the stability of the composite. The design of a gravity-driven rattan-based catalytic filter for wastewater treatment provides an effective strategy for developing renewable and continuous catalytic systems.