Three-dimensional MOF-derived hierarchically porous aerogels activate peroxymonosulfate for efficient organic pollutants removal

Abstract

The preparation of macroscopic objects from metal-organic frameworks (MOFs) derived carbon-based materials is challenging but of great significance to broaden their industrial application. In this work, we have provided a green and effective strategy to synthesize a three-dimensional (3D) compressible Fe-doped nitrogen carbon/gelation aerogel (Fe@NC-800/AG) via a freeze-drying and low-temperature calcination technique. The Fe@NC-800 powders were uniformly and tightly dispersed in the channels of 3D AG. Interestingly, the Fe@NC-800 can function as the mechanical support skeleton and provide catalytic sites to activate peroxymonosulfate (PMS) for degrading various organic pollutants in aqueous solution. The Fe@NC-800/AG/PMS system exhibited outstanding tetracycline (TC) degradation performance (94.3% of TC can be removed after 60 min) and recycling ability (after reused for 10 times, the TC removal efficiency can reach to 90%). Moreover, the integrated multilayer filter composed of two pieces of Fe@NC-800/AG showed high TC removal efficiency (>90%) at the flux of 2.22 mL/min for 420 min. The Fe@NC-800/AG composite with hierarchical pore structure greatly reduced diffusion resistance of pollutants and the 3D compressible property made Fe@NC-800-0.15/AG composite can be easily separated from aqueous solution, which reduced secondary pollution and improved recycling performance. This study provided a feasible strategy to immobilize MOF-derived powders into compressible and tailorable form, which held a novel promise for rationally fabricating 3D MOF-based catalyst with structural diversity.