Porous Cu-Bi loaded bamboo charcoal prepared by the citric acid complexation method for efficient photo-assisted peroxymonosulfate activation to remove antibiotic pollution

Developing inexpensive and highly active biochar for advanced oxidation processes is crucial for addressing water pollution problems. Here, Bi 2 O 3 /CuBi 2 O 4 /Cu x O multi-active sites loaded bamboo charcoal (Cu/Bi-BC) was fabricated by pyrolysis of a citric acid/Cu 2+ /Bi 3+ complex modified bamboo powder. Firstly, the chemical structure, morphology, and adsorption properties of Cu/Bi-BC were studied. Then, the catalytic performance of Cu/Bi-BC was evaluated through H 2 O 2 activation, photo-H 2 O 2 activation, peroxymonosulfate (PMS) activation, and photo-PMS activation. Our results revealed that 98.9% of tetracycline (TC) could be removed within 10 min in the Cu/Bi-BC-500/PMS/Visible-light catalytic system with a rate constant ( k ) of 0.4509 min − 1 . This rate constant is 2.50 times that in the Cu/Bi-BC-500/PMS system (k = 0.1796 min − 1 ). In the presence of Cu/Bi-BC, visible-light could significantly improve the activation efficiency of both PMS and H 2 O 2 , and the activation of PMS was more efficient than that of H 2 O 2 . The photoassisted activation mechanism was investigated through a comprehensive approach encompassing electrochemical analysis, quenching experiments, and density functional theory calculations. The redox cycle of Cu(I)/Cu(II) and the formation of metastable Cu/Bi-BC-PMS complexes accelerate the transfer of electrons to PMS, generating a series of reactive oxygen species. The degradation of TC in the Cu/Bi-BC-500/PMS system mainly depends upon the non-radical process of 1 O 2 , while ·OH and ·O 2 − are the main active radicals in the Cu/Bi-BC-500/H 2 O 2 system. Degradation pathways, ecotoxicity assessments, and wheat germination toxicity were also investigated.