Eosin Y Covalently Modified on Graphene Oxide for Enhanced Photocatalytic Activity toward the Degradation of Antibiotic Cefaclor under Visible Light Irradiation

Abstract

The covalent immobilization of eosin Y (EY) on graphene oxide (GO) was prepared and the obtained GO/EY composite can be used as a visible‐light‐driven photo‐catalyst for the degradation of cefaclor (CEC) antibiotics. The GO/EY composite exhibited much higher photocatalytic activity than pure GO and EY adsorbed GO. Using 2 mg L−1 of CEC at pH=7, 97 % degradation toward CEC could be achieved after irradiation time of 45 min. The enhanced photocatalytic activity for GO/EY composite can be attributed to the modification of GO by EY, which acted as a sensitizer for enhancing visible light absorption. The affecting factors of photocatalytic activities on the photocatalytic degradation of CEC were evaluated, including the effects of pH values, the photosensitized oxidation conditions and the reusability of the photocatalyst. Furthermore, the enhanced photocatalytic mechanism induced by visible‐light responsive GO/EY composite was proposed by reactive specie trapping experiments, and 1O2 and H2O2 were determined to be the main reactive oxygen species in the photocatalytic system. All these results demonstrated that organic dye sensitizer functionalized GO provided a nice candidate as a photocatalyst for the removal of CEC antibiotic from water under visible light irradiation.

Anthraquinone and its Derivatives as a Recyclable Photocatalyst for Efficient Photocatalytic Degradation of Rhodamine B in Water under Visible Light

“…Taking into account that the photocatalytic experiment was conducted in an open gas system with the presence of air, it is necessary to take into account and investigate the presence of superoxide radical anion (O 2 ⋅ − ), hydroxyl radicals (•OH), and oxygen vacancies (holes, h + ). This is accomplished by introducing 1.2 equivalents of benzoquinone, which is a quencher of O 2 ⋅ − , isopropanol, which is a quencher of •OH, and sodium oxalate, which is a quencher of h + , into the photocatalytic system [67–70] . As shown in Figure 8, with the addition of 1.2 equiv.…”

“…This is accomplished by introducing 1.2 equivalents of benzoquinone, which is a quencher of O 2 *À , isopropanol, which is a quencher of * OH, and sodium oxalate, which is a quencher of h + , into the photocatalytic system. [67][68][69][70] As shown in Figure 8, with the addition of 1.2 equiv. sodium oxalate, benzoquinone and isopropanol, the removal efficiency of RhB has undergone a reduction of varied degrees compared with the case of no addition of any scavengers and the reduction of RhB removal efficiency present an increasing sequence of NaC 2 O 4 < IPA < BQ.…”