The hierarchically nitrogenous magnetic porous carbon prepared by ZIF-67 through mesoporous silica-protected calcination for rapid Cr(VI) removal

A novel magnetic composite with hierarchically porous nature is prepared by a facile synthetic strategy for the highly toxic chromium (Cr(VI)) removal. The magnetic NMPC@mSiO(2) with defined mesoporous shell is successfully fabricated by one-step carbonization of ZIF-67@mSiO(2), which is prepared through a simple one-pot method. Benefiting from the protection of mSiO(2) during pyrolysis process, NMPC@mSiO(2)-800 owns high specific surface area, hierarchically porous structure and increased C-N content. It shows an excellent Cr(VI) removal performance with an adsorption capacity rising to 158.11 mg.g(-1) from 78.60 mg.g(-1) (NMPC-800). Moreover, the prepared NMPC@mSiO(2)-800 exhibits antijamming capability for Cl-1/SO42- witha negligible adverse impact on Cr(VI) removal. The kinetic studies show that the Cr(VI) removal on NMPC@mSiO(2)-800 confirms to pseudo-second-order model equipped with a relatively large adsorption rate constant, revealing the ability to quickly adsorb Cr(VI). The thermodynamic parameters manifest Cr(VI) adsorption is spontaneous and endothermic. Besides, the NMPC@mSiO(2)-800 can be quickly recovered from the system due to the magnetic porous carbon. Herein, NMPC@mSiO(2)-800 has a broad application prospect in Cr(VI) removal due to its excellent adsorption capacity, good antijamming ability, high adsorption rate and easy magnetic separation.

Automated summary

A novel magnetic composite with hierarchically porous structure was successfully prepared for the removal of highly toxic chromium (Cr(VI)) through a simple synthetic strategy. The composite exhibited excellent Cr(VI) removal performance and anti-jamming ability, making it a promising candidate for practical applications.