The self-sufficient heterogeneous photo-Fenton (SH-PF) system was constructed for doxycycline hydrochloride (DOH) degradation with hydroxyapatite (Hap) modified CuFeO 2 (Hap/CuFeO 2 ) composites through H 2 O 2 in-situ production. The modification of Hap could improve the specific surface area, visible-light response, light conversion efficiency, photoelectron lifetime and oxygen vacancies (OVs) of CuFeO 2 , which was conducive to H 2 O 2 production and DOH degradation in SH-PF system. Notably, Hap/CuFeO 2 fabricated with 0.5 g Hap (Hap/CuFeO 2 -0.5) displayed more superior performance for DOH degradation compared to other synthesized catalysts. The Hap/CuFeO 2 -0.5 load and initial solution pH for DOH degradation in SH-PF system were optimized, and the Hap/CuFeO 2 -0.5 had good reusability and stability. The • OH was the main active species for DOH degradation, and the facilitation effect of • O 2 – and photoelectrons on DOH degradation was associated with the H 2 O 2 production in the present work. In addition, the capture of photogenerated holes suppressed the recombination of photogenerated carriers, elevating the production of photoelectrons and thereby enhancing H 2 O 2 production and DOH degradation. The degradation pathways for DOH were proposed and the comprehensive toxicities of DOH were relieved after degradation in SH-PF system.
Antibiotics are a new type of environmental pollutants. Due to its wide application in many fields, antibiotic residues are ubiquitous in the wastewater environments. Given their potential threat on water ecosystem functioning and public health, the detection of antibiotic residues in wastewater environments has become very necessary. Based on the complexation of Al 3+ with flumequine (FLU), ciprofloxacin (CIP) and doxycycline hydrochloride (DOX), their molecular conjugated area were increased and fluorescence intensity were enhanced, combined with synchronous fluorescence spectrometry (SFS) had good selectivity and high sensitivity, a novel method of Al 3+ sensitized synchronous fluorescence spectrometry for the determination of FLU , CIP and DOX residues in wastewater was established. When the wavelength difference (Δλ) was selected 115.0 nm, synchronous fluorescence spectra of the three antibiotics could be well separated and the interference of wastewater matrix were eliminated primely. The new SFS made good use of spectral separation instead of conventional chemical separation, and the actual wastewater sample could be directly determined after simple filtration. The experiment results showed that the concentrations of FLU, CIP and DOX in the range of 0.5000–800.0 ng·mL -1 , 0.5000–640.0 ng·mL -1 and 10.00–3500 ng·mL -1 had a good linear relationship with fluorescence intensity. The detection limits of three antibiotics were 0.02054 ng·mL -1 , 0.03956 ng·mL -1 and 0.8524 ng·mL -1 , respectively. Recovery rates of three antibiotics in wastewater samples were 90.72%-98.23%, 88.68%-95.08% and 85.94%-96.70%. The new SFS established in this experiment had the advantages of simple, rapid, sensitive, accurate and good selectivity. Simultaneous and rapid detection of FLU, CIP and DOX residues in wastewater was successfully realized. It had good application prospects in real-time water quality monitoring.