Efficient photocatalytic degradation of high-concentration moxifloxacin over dodecyl benzene sulfonate modified graphitic carbon nitride: Enhanced photogenerated charge separation and pollutant enrichment

Photocatalysis technology has been proved to be a promising strategy to eliminate antibiotic pollution from wastewater, in spite of arduous challenges such as insufficient utilization of sunlight, high recombination of photogenerated charges, low efficiency of high-concentration antibiotics, and infrequent investigation on new antibiotics. Herein, we synthesized a visible-light-driven (VLD) photocatalyst by modifying dodecyl benzene sulfonate (DBS) onto graphitic carbon nitride nanosheet (CNNS), and studied its photocatalytic performance for removing high-concentration moxifloxacin (MOX), a fourth-generation quinolone antibiotic. Compared with other studies (Table S1), this catalyst broke through the bottleneck of degradation of high concentration MOX, which could remove 100 mg L-1 MOX under 30 min of irradiation. The hydrophobic dodecyl benzene group and the formed sulfonyl group with strong electron-withdrawing property were beneficial to boost the MOX enrichment from the bulk solution and suppress the recombination of photogenerated charges. The effect of pH value, MOX concentration and photocatalyst dosage was also studied in order to explore the best photocatalytic reaction condition. The superior photocatalytic durability and practical application prospects of DBS/CNNS were also demonstrated. By revealing the band structure of the DBS/CNNS hybrid, as well as the active species and the intermediate products generated in the photocatalytic process, a plausible photocatalytic mechanism was pro-posed. This study indicates that the DBS/CNNS hybrid is a potential VLD photocatalyst for efficient elimination of high-concentration antibiotics in wastewater.

Automated summary

A visible-light-driven photocatalyst, DBS/CNNS, has been synthesized and applied for the elimination of high-concentration antibiotics in wastewater. It demonstrated efficient degradation of moxifloxacin (MOX) under visible light irradiation, breaking through the bottleneck of degrading high concentration antibiotics. The hydrophobic dodecyl benzene group and the formed sulfonyl group with strong electron-withdrawing property were beneficial for MOX enrichment and charge recombination suppression.