Surfactant Pyrolysis-Guided in Situ Fabrication of Primary Amine-Rich Ordered Mesoporous Phenolic Resin Displaying Efficient Heavy Metal Removal

A unique strategy for the direct preparation of primary amine-functionalized ordered mesoporous phenolic resin (NH2-MPRN) was presented. The essence of our approach avoided the side reactions in the m-nitrophenol–formaldehyde resol synthesis using m-nitrophenol and formaldehyde as the monomers. Importantly, these resols can efficiently assemble with triblock copolymer F127 to form a mesostructured composite. The final prolysis treatment removed the F127 template to produce ordered mesopores, and meanwhile, the accompanying reductive gas in situ transferred the nitro groups to primary amines. Notably, the obtained NH2-MPRN material delivered fast toxic hexavalent chromium sorption kinetics with high uptake capacity and selectivity due to a mesoporous structure, high amine availability, and a hydrophobic surface. Interestingly, almost all of adsorbed chromium species existed as low-toxic trivalent chromium in the resin owing to the cooperative detoxification process by the neighboring primary amines and phenolic hydroxyl groups. Also, it showed the reversible detoxification for at least five times.