Visible-Light-Driven Photocatalytic Degradation of Tetracycline Using Heterostructure Cu2O−TiO2 Nanotubes, Kinetics, and Toxicity Evaluation of Degraded Products on Cell Lines
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Date
2022-09
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Abstract
This study first reports on the tetracycline photodegradation with thesynthesizedheterostructuredtitaniumoxidenanotubescoupledwithcuprous
oxide photocatalyst. The large surface area andmore active sites onTiO2
nanotubes with a reduced band gap (coupling of Cu2O) provide faster
photodegradation of tetracycline under visible light conditions. Cytotoxicity
experiments performed on theRAW264.7 (mousemacro phage) andTHP-1
(humanmono cytes)cell lines of tetracycline and the photodegradedproductsof
tetracyclineaswellasquenchingexperiments werealsoperformed.Theeffectsof
different parameters likepH, photocatalyst loadingconcentration, cuprousoxide
concentration, and tetracycline load on the photodegradation rate were
investigated.Withanenhancedsurfaceareaof nanotubes anda reducedband
gap of 2.58 eV, 1.5 g/L concentration of 10%C-TAC showed the highest
efficiencyofvisible-light-drivenphotodegradation(∼100%photodegradationrate
in60min)of tetracyclineatpH5,7, and9.Thephotodegradationefficiencyisnotdepleteduptofiveconsecutivebatchcycles.
Quenchingexperiments confirmed that superoxide radicals andhydroxyl radicals are themost involved reactive species in the
photodegradationoftetracycline,whilevalancebandelectronsaretheleastinvolvedreactivespecies.Thecytotoxicitypercentageof
tetracyclineanditsdegradedproductsonRAW264.7(−0.932)aswellasTHP-1(-0.931)showedanegativecorrelationwiththe
degradationpercentagewith a p-value of 0.01. The toxicity-free effluent of photodegradation suggests the applicationof the
synthesizedphotocatalyst inwastewater treatment.