Antibiotic residues entering the
ecological environment not only
cause serious environmental pollution but also may cause the development
of resistance genes and other ecological risks. Therefore, the degradation
of antibiotic contaminants has become a research hot spot. Herein,
a new Z-scheme BiVO4/exfoliated g-C3N4 heterojunction photocatalyst was synthesized for efficient tetracycline
photodegradation with the assistance of peroxymonosulfate under visible
light irradiation. The influence of different key environmental factors,
including peroxymonosulfate concentrations, coexisting ions, and solution
pH, on the photodegradation efficiency of tetracycline was comprehensively
studied. The optimized BiVO4/exfoliated g-C3N4–0.6 was demonstrated to exhibit excellent photodegradation
performance of tetracycline with an apparent kinetic constant of ca.
0.128 min–1 with 0.3 mM peroxymonosulfate, which
was ca. 3 times of exfoliated g-C3N4 (0.0415
min–1) under the same conditions and about 16 times
and 5 times of bulk g-C3N4 (0.0080 min–1) and exfoliated g-C3N4 (0.0285 min–1) without peroxymonosulfate, respectively. The BiVO4/exfoliated
g-C3N4–0.6 showed only about 5% reduction
in the degradation efficiency of tetracycline after six consecutive
cycle experiments. The free radical scavenging test and electron spin
resonance characterization results suggested that •O2
–, h+, •SO4
–, •OH, and 1O2 were all involved in
the catalytic oxidative process of tetracycline in the BiVO4/exfoliated g-C3N4–0.6, peroxymonosulfate
and light reaction system. This study not only offers an attractive
Z-scheme heterojunction photocatalyst for tetracycline degradation
but also demonstrates a promising way to use peroxymonosulfate for
advanced wastewater treatment.