Co₃(PO₄)₂/Ag₃PO₄ with enhanced simulated sunlight photocatalytic activity toward ofloxacin degradation and mechanism insight

Abstract

BACKGROUND Ofloxacin is a frequently detected fluoroquinolone antibiotic in wastewater treatment plant effluents, sea waters and surface waters. Photocatalytic technology is considered to be the most promising treatment technology for the removal of ofloxacin. However, it is a big challenge to exploit a novel sunlight‐driven photocatalyst and reveal the mechanism of ofloxacin degradation. RESULTS Co3(PO4)2/Ag3PO4 composites were prepared using a facile hydrothermal synthesis method. The structural, morphological and optical properties of the composites were well characterized. Both the degradation efficiency and cyclical stability of the Co3(PO4)2/Ag3PO4 composites increased significantly under simulated sunlight irradiation when ofloxacin (OFX) or methyl orange (MO) was used as the target molecule, as compared with single‐phase Ag3PO4 and Co3(PO4)2. The reduction of antimicrobial activity for 8%Co3(PO4)2/Ag3PO4 reached 88.8% after 5 min of sunlight irradiation. CONCLUSION Co3(PO4)2 played a critical role in suppressing carrier recombination and provided a large number of photogenerated holes and •O2− to oxidize OFX or MO. The OFX degradation mechanism included piperazinyl dealkylation, decarboxylation and defluorination. The reduction of antimicrobial activity for degradation byproducts was obvious after simulated sunlight irradiation over Co3(PO4)2/Ag3PO4. Therefore Co3(PO4)2/Ag3PO4 is an attractive candidate for the removal of OFX. © 2019 Society of Chemical Industry

Mechanism insight into the photocatalytic degradation of fluoroquinolone antibiotics by the ZIF-8@Bi2MoO6 heterojunction

“…90–92 The third pathway is the removal of the piperazine ring to form an unidentified product M 4 ( m / z = 277), followed by removals of the hydroxyl group, the CO group of the carboxyl group, and the F atom to form products M 9 ( m / z = 261), M 13 ( m / z = 234), and M 18 ( m / z = 216), respectively. 93,94 In the fourth pathway, the simultaneous removal of the piperazine ring and the carboxyl group forms a product M 5 ( m / z = 231), 93 followed by the removal of the F atom and then the methyl group to form products M 10 ( m / z = 212) and M 14 ( m / z = 198), respectively. At the same time, the breakdown of the benzoxazine ring forms products M 15 ( m / z = 194) and M 19 ( m / z = 177).…”

Application of visible light active photocatalysis for water contaminants: A review

“…The electrodeposition method is a type of plating by depositing material on a substrate through electrochemical reduction (Hasan et al, 2019) and has been applied in photocatalyst preparation. Reactive materials developed using this method include Au/ZnO film (da Silva et al, 2013), TiO 2 film (Hachisu et al, 2016), and TiO 2 on a silicon wafer surface (Basheer et al, 2020).…”

“…The mechanism of modified photocatalyst composites, except for the reactions above, usually includes the transfer of e À and h + between different photocatalysts, due to the different band potential (Geng et al, 2019;B. S. Li, Lai, et al, 2019).…”

Construction of Co3(PO4)2/g-C3N4 nanowire composites to boost visible-light-driven photocatalysis

“…Cobalt phosphate (Co 3 (PO 4 ) 2 ) is a promising candidate because of its economy, narrow band gap, strong visible light capture ability, non-toxicity and environmental compatibility. 13,14 More importantly, Co 3 (PO 4 ) 2 not only has an energy band position suitable for overall water splitting, but also has a matching energy level with g-C 3 N 4 , which makes it possible to design Co 3 (PO 4 ) 2 /g-C 3 N 4 nanocomposites to achieve water splitting. Recently, Co 3 (PO 4 ) 2 /g-C 3 N 4 heterostructure photocatalysts with 0D, 2D and 3D morphologies have been synthesized using a photo-deposition method, demonstrating enhanced photocatalytic activity.…”