Enhanced Activation of Persulfate by Co-Doped Bismuth Ferrite Nanocomposites for Degradation of Levofloxacin Under Visible Light Irradiation

Abstract

In this study, magnetic visible light driven photocatalysts (bismuth ferrite, Bi2Fe4O9, BFO and Co-doped bismuth ferrite, Co-BFO) were successfully prepared by the facile hydrothermal method. The catalyst was used in the application of heterogeneous persulfate (PS) system under visible LED light irradiation for the degradation of levofloxacin (LFX), proving to be an excellent photocatalyst when evaluated by various characterization methods. The effect of Co-doping in the BFO structure was investigated that the decrease of band gap width and the generated photoelectrons and holes would effectively reduce the recombination of photogenerated electron-hole pairs, leading to the enhancement photocatalytic activity. The results demonstrated that Co-BFO catalyst had a high photodegradation efficiency over a wide pH range of 3.0–9.0 and the Co-BFO-2 composite displayed the optimal catalytic performance. It was found that the degradation rate of LFX by Co-BFO-2 catalyst was 3.52 times higher than that of pure BFO catalyst under visible light condition. The free radical trapping experiments and EPR tests demonstrated that superoxide, photogenerated holes and sulfate radicals were the main active species in the photocatalytic degradation of LFX. And a possible photocatalytic degradation mechanism of LFX was proposed in the Vis/Co-BFO/PS process. These findings provided new insight of the mechanism of heterogeneous activation of persulfate by Co-BFO under visible light irradiation.

Enhancement of Multiferroic and Optical Properties in BiFeO3 Due to Different Exchange Interactions Between Transition and Rare Earth Ions

“…where α is the absorption coefficient, h is the Planck constant, A is a constant, ν is the photon's frequency, E g is the band-gap, and n = 1/2; n value provides a detailed overview of the transition in a material. The Tauc plot shows that the BTFMO91 system has a bandgap at energy E g = 1.83 eV, which is similar to as observed by Kumari et al, Zhong et al, Pattnaik et al [40][41][42] As M. Sakar et al have discussed in their system that due to Dy doping, there is the formation of a new electronic state of Dy 3þ underneath the pure BFO material. Similarly in our system, we have doped Tb at the Bi site, thus there may be the formation of the new electronic state of Tb 3þ , as a result, the bandgap decreased in our system.…”

Invasion of Zinc in BiFeO3/Bi25FeO40 Perovskite-Structured Material as an Efficient Electrode for Symmetric Supercapacitor

“…Figure a shows the full survey spectrum, indicating Bi 4f, O 1s, Fe 2p, and Zn 2p in BFO and BFZO1. Figure b shows the XPS spectrum with the characteristic peaks at 1020.65 and 1041.77 eV belonging to Zn (2p 3/2 and 2p 1/2 ) spin–orbit, which strongly confirms the presence of Zn 2+ ions in BFZO1 . The Bi 4f spectrum of BFO and BFZO1 is shown in Figure f,c and the peaks were observed at 157.46, 158.14, and 162.97 eV for BFO, and at 158.16, 159.24, and 163.59 eV for BFZO1 corresponds to two spin–orbit splitting of Bi 4f 5/2 and Bi 4f 7/2 , which confirms the presence of Bi 3+ …”

“…Figure 3b shows the XPS spectrum with the characteristic peaks at 1020.65 and 1041.77 eV belonging to Zn (2p 3/2 and 2p 1/2 ) spin−orbit, which strongly confirms the presence of Zn 2+ ions in BFZO1. 28 The Bi 4f spectrum of BFO and BFZO1 is shown in Figure 3f,c and the peaks were observed at 157.46, 158.14, and 162.97 eV for BFO, and at 158.16, 159.24, and 163.59 eV for BFZO1 corresponds to two spin−orbit splitting of Bi 4f 5/2 and Bi 4f 7/2 , which confirms the presence of Bi 3+ . 29 Figure 3g shows Fe 2p spectrum of BFO positioned at 709.50 eV (Fe 3+ 2p 3/2 ), 713.43 eV (Fe 3+ 2p 3/2 ), and 723.15 (Fe 2+ 2p 1/2 ).…”

A Mini Review on Persulfate Activation by Sustainable Biochar for the Removal of Antibiotics

“…Persulfate-based advanced oxidation processes (PS-AOPs) can induce the generation of highly reactive radicals (sulfate radicals (SO 4 •− ), hydroxyl radicals (•OH), and superoxide radicals (O 2 •− )) to degrade antibiotics into other compounds, water (H 2 O), and carbon dioxide (CO 2 ). The persulfates (peroxymonosulfate (PMS) and peroxydisulfate (PDS)) can be activated via ultraviolet light, heat, ultrasound, carbon materials, and transition metals, generating active radicals [ 11 , 12 ]. To overcome the disadvantages of additional energy consumption, high cost, and the problem of metal leaching, the utilization of biochar materials in PS activation has generated increasing attention.…”