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Photocatalysis degradation of tetracycline hydrochloride with high concentration over a hollow microsphere S-doped g-C 3 N 4. [Display omitted] For the past few years, graphitic carbon nitride (g-C 3 N 4) has been widely used to eliminate environmental pollutants, but limited active site on surface and low separation/migration ability suppress its practical uses. Herein, we adopted a supramolecular self-assembly route followed with S doping to synthesize S-doped g-C 3 N 4 with a hollow microsphere composition (SCNHM), where the shell was demonstrated to compose of ultrathin nanosheets. The unique structural characteristics endow the SCNHM with high specific surface area (∼81 m2 g−1) to provide abundant reaction sites and enhanced light-harvesting due to the light-scattering effect of hollow structure. Moreover, the S dopant meliorated the electronic structure to narrow the bandgap and promoted the charge separation/transfer capability. With this synergistic effect, the SCNHM presented greatly improved photocatalytic activity for degrading tetracycline hydrochloride (TC) compared to the CN, SCN and CNHM samples. This photocatalyst could eliminate high-concentration TC (50 mg L−1) in 18 min, and the 30 min removal efficiencies of 100 mg L−1 and 200 mg L−1 reached 92 % and 60 %, which is much better than the reported photocatalysts in literatures (usually ≤ 20 mg L−1). Additionally, the good photocatalytic durability was confirmed and the degradation pathway of TC was proposed. Furthermore, the SCNHM was proved to meanwhile possess superior performance for inactivating the typical Gram-positive bacterium of Staphylococcus aureus (S. aureus) and the typical Gram-negative bacterium of Escherichia coli (E. coli). Finally, based on determination of band alignment and detection of active species, a plausible photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

Visible-light-driven photocatalytic degradation of moxifloxacin over a aminobenzaldehyde grafted graphitic carbon nitride. [Display omitted] Graphitic carbon nitride (GCN) has been demonstrated to be a potential visible-light-driven photocatalyst for eliminating organic pollutants. However, its practical application is limited by low photocatalytic efficiency originating from high recombination of photogenerated charges. In this work, the electronic structure of GCN was regulated by doping aminobenzaldehyde (ABA) into the skeleton through a solid-state Schiff base reaction. Photoelectrochemical characterizations illustrated that the obtained catalyst (CNABA) exhibited narrower band gap, lower recombination rate of photoinduced electron-hole pair and higher charge transfer ability than the pristine GCN, further indicating its excellent photocatalytic activity. Using moxifloxacin (MOX) as a model pollutant, the ABA doping content was firstly optimized and the optimal activity of the CNABA photocatalyst was 3.1 times higher than that of the GCN. Subsequently, the effects of pH value, photocatalyst dosage and MOX concentration on the photocatalytic behavior were also studied. Superior stability and photocatalytic reusability were confirmed by five repeated tests. By substituting tap water/natural lake water for deionized water and sunlight for xenon light, the CNABA also exhibited high elimination efficiency, implying its good practicability. Superoxide radical, hydroxyl radical and photogenerated hole were identified as the main active species to degrade MOX. Finally, possible degradation pathways for MOX to mineralize small molecules were proposed by determining intermediate products during photocatalysis. This work provides a solid-state method to rationally design aromatic system-modified GCN photocatalysts, and the obtained CNABA is a promising visible-light-driven photocatalyst for eliminating antibiotics. [ABSTRACT FROM AUTHOR]

Visible-light-driven photocatalytic degradation of moxifloxacin over a aminobenzaldehyde grafted graphitic carbon nitride. [Display omitted] Graphitic carbon nitride (GCN) has been demonstrated to be a potential visible-light-driven photocatalyst for eliminating organic pollutants. However, its practical application is limited by low photocatalytic efficiency originating from high recombination of photogenerated charges. In this work, the electronic structure of GCN was regulated by doping aminobenzaldehyde (ABA) into the skeleton through a solid-state Schiff base reaction. Photoelectrochemical characterizations illustrated that the obtained catalyst (CNABA) exhibited narrower band gap, lower recombination rate of photoinduced electron-hole pair and higher charge transfer ability than the pristine GCN, further indicating its excellent photocatalytic activity. Using moxifloxacin (MOX) as a model pollutant, the ABA doping content was firstly optimized and the optimal activity of the CNABA photocatalyst was 3.1 times higher than that of the GCN. Subsequently, the effects of pH value, photocatalyst dosage and MOX concentration on the photocatalytic behavior were also studied. Superior stability and photocatalytic reusability were confirmed by five repeated tests. By substituting tap water/natural lake water for deionized water and sunlight for xenon light, the CNABA also exhibited high elimination efficiency, implying its good practicability. Superoxide radical, hydroxyl radical and photogenerated hole were identified as the main active species to degrade MOX. Finally, possible degradation pathways for MOX to mineralize small molecules were proposed by determining intermediate products during photocatalysis. This work provides a solid-state method to rationally design aromatic system-modified GCN photocatalysts, and the obtained CNABA is a promising visible-light-driven photocatalyst for eliminating antibiotics. [ABSTRACT FROM AUTHOR]