Fe3C@C/C for catalytic ozonation of silicon-containing wastewater: Dual improvement of silicon resistance and catalytic effect

• An Fe 3 C@C/C catalyst was synthesized in situ using a one-step method • Fe 3 C@C/C was first used to investigate the resistance of Si during catalytic ozonation • Fe 3 C particles acted as the main active sites of the catalyst • Silicon resistance of the Fe 3 C was maximized via the carbon-encapsulated structure • The activation of O 3 was unimpeded by the carbon-encapsulated structure The improvement of catalysts’ stability under harsh reaction conditions is vital for their practical applicability. Herein, iron carbide (Fe 3 C) nanoparticles were encapsulated in graphitic carbon in situ and a carbon ball served as the carrier. The synthesized Fe 3 C@C/C was first utilized to treat an m-cresol wastewater containing Si via catalytic ozonation. Compared with the commercial Fe/Al 2 O 3 catalyst, the resistance to Si of the Fe 3 C@C/C was improved 22.68 times, while the TOC removal rate increased by a factor of 2.9, and it remained stable during 10 cycles and 12000 min of continuous reaction, which further demonstrated its potential for diverse applications. The catalyst exhibits improved resistance to Si because of the dual protection from the carbon-encapsulated structure and carbon carrier. Density functional theory calculations show that the encapsulation of Fe 3 C using carbon significantly increases the resistance to adsorption of Si on its active sites. In addition, the activation of O 3 is unimpeded on the Fe 3 C adsorption sites by the protection from C, thus the generation of reactive oxygen species (ROS) by ozone is largely promoted. The mechanism associated with the resistance of the Fe 3 C@C/C catalyst to Si and its elevated activity are also elucidated.