Search

LaFeO 3 /MgFe 2 O 4 heterojunctions were prepared via the sol-gel route to enhance solar-light induced photo-persulfate degradation of tetracycline hydrochloride (TCH). LaFeO 3 /MgFe 2 O 4 exhibited the better removal efficiency of TCH in comparison to LaFeO 3 and MgFe 2 O 4. The photo-persulfate activity of LaFeO 3 /MgFe 2 O 4 was intensively affected by LaFeO 3 content, pH, and inorganic salts. Under the optimal conditions, 2-LaFeO 3 /MgFe 2 O 4 with a nominal LaFeO 3 content of 10 wt % presented the removal efficiency of 97.01 %, while declined to 85.40 % after ninth-cycle test. The lattice defects formed in LaFeO 3 and MgFe 2 O 4 acted as the active sites for TCH adsorption and photon capture. The oxygen-defected tight interface between LaFeO 3 and MgFe 2 O 4 was favorable for the separation and migration of photo-induce e-/h+ pairs, boosting solar-light response for photo-persulfate activity of LaFeO 3 /MgFe 2 O 4. However, the long-term photo-corrosion inevitably induced to the change in valance states of surface compositions, weakening the photo-persulfate performance in TCH elimination. [Display omitted] • LaFeO 3 /MgFe 2 O 4 hybrids were prepared via the sol-gel approach. • LaFeO 3 /MgFe 2 O 4 had the strong solar-light photo-persulfate activity for TCH degradation. • The tight interface favored the transfer and migration of photo-induced e-/h+ pairs. • Photo-induced radicals and Fe2+/Fe3+ couples promoted the persulfate oxidation. [ABSTRACT FROM AUTHOR]

Metal oxides-based heterojunction fabrication is a promising strategy to eliminate antibiotics from wastewater via adsorption-photocatalysis. ZnLa x Bi 2−x O 4 hybrids with various La/Bi molar ratios were fabricated for enhancing the adsorption-photocatalytic elimination of tetracycline hydrochloride (TCH). Oxygen-defected ZnLa x Bi 2−x O 4 composites provided the sufficient sites for photon capture and pollutants adsorption. In addition, the tight p-n-p type interface among oxygen-defected La 2 O 3 , ZnO, and spinel ZnBi 2 O 4 favored the rapid transfer and migration of photo-excited e-/h+ pairs, enlarging the visible light utilization. Hence, ZnLa x Bi 2−x O 4 samples had the better adsorption-photocatalytic activity than ZnLa 2 O 4 and ZnBi 2 O 4 for TCH removal. Langmuir and second-order models well described the adsorption isotherms and kinetics of ZnLa x Bi 2−x O 4 samples, respectively. The adsorption capacity of optimal ZnLa 1.75 Bi 0.25 O 4 with a La/Bi molar ratio of 7:1 was 406.85 mg g−1, and its removal efficiency of 210 mg L−1 TCH solution was 98.04 % within 150 min. The change in valence states of surface compositions induced to the declined removal efficiency of ZnLa 1.75 Bi 0.25 O 4 to 91.95 % after five cycle times. [Display omitted] • ZnLa x Bi 2−x O 4 heterojunctions had the excellent adsorption-photocatalytic activities. • The adsorption capacity of optimal of ZnLa 1.75 Bi 0.25 O 4 was 406.85 mg g−1. • The removal efficiency of 210 mg L−1 TCH solution over ZnLa 1.75 Bi 0.25 O 4 was 98.05 %. • Langmuir and second-order models well fitted with the adsorption behaviors of ZnLa x Bi 2−x O 4. [ABSTRACT FROM AUTHOR]