High-efficiency removal of tetracycline by carbon-bridge-doped g-C3N4/Fe3O4 magnetic heterogeneous catalyst through photo-Fenton process

• Published in: Journal of hazardous materials Vol. 418; p. 126333
• Main Authors: Zhang, Xiao, Ren, Bin, Li, Xi, Liu, Biming, Wang, Shiwen, Yu, Peng, Xu, Yanhua, Jiang, Guoqiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2021
• Subjects: carbon nitride; catalysts; Copolymerization; H2O2 decomposition; light; magnetism; Malonamide; melamine; mineralization; oxidation; Photo-Fenton; Tetracycline; toxicity; urea; wastewater treatment; Photo-Fenton; Malonamide; Copolymerization; H2O2 decomposition; Tetracycline
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.126333

Carbon-bridge-modified malonamide (MLD)/g-C3N4 (CN) was prepared by copolymerization of MLD with urea and melamine and loaded with Fe3O4 for the high-efficiency removal of tetracycline (TC) in water under photo-Fenton. The prepared catalysts were characterized by SEM, TEM, N2 adsorption–desorption analysis, XPS, XRD, and FTIR, which proved that the modification method successfully introduced the C bridge into the carbon nitride molecular system and increased the structural defects of the catalyst. The Carbon-bridge-modified MLD/CN/Fe3O4 also had good visible-light response and charge-separation and transport abilities in the photoelectrochemical test. Degradation results showed that the photo-Fenton degradation of TC reached 95.8%, and the mineralization rate was 55.7% within 80 min at 80 mM H2O2 dosage, 0.5 g/L catalyst dosage, and near-neutral pH by 0.8MLD/CN/Fe3O4. Moreover, the oxidation products and mineralization pathways of TC were explored by LC-MS. Toxicity analysis indicated low environmental threat of the intermediates in TC mineralization. EPR analysis and H2O2 decomposition efficiency analyses showed an improvement in the H2O2 decomposition performance of 0.8MLD/CN/Fe3O4. This work could provide a valuable insight for the application of heterogeneous photo-Fenton technology in wastewater treatment. [Display omitted] •A carbon-bridge modified MLD/CN/Fe3O4 catalyst was successfully synthesized by copolymerization.•Carbon-bridge implantation significantly improved the charge separation performance of the catalyst.•0.8MLD/CN/Fe3O4 has good degradation performance for TC under photo-Fenton within a wide pH range.•The mechanism of enhanced decomposition of H2O2 and degradation of TC was proposed.