Photocatalysis technology has been considered a green and efficient method to control tetracycline hydrochloride (TCH) pollution in potable water sources. In this paper, Bi 2 WO 6 -loaded photocatalysts on nitrogen-defective C 3 N 4 (BWO@ND-C 3 N 4 ) were constructed to synergistically promote the degradation of TCH under visible light by activating periodate (PI). TCH (20 mg/L) could be 100 % photo-degraded by BWO@ND-C 3 N 4 (0.25 g/L) within 30 min when PI concentration is 1 mM. The BWO@ND-C 3 N 4 /activated PI system can also complete total TCH degradation when applied to actual water bodies and sunlight particularly (40 min for sunny days and 60 min for cloudy days). Besides, the system displayed good recycling stability under visible light, maintaining 90 % TCH degradation efficiency after 6 cycles. The degradation mechanism research showed that ·IO 3 , h + , ·OH, ·O 2 – and 1 O 2 are the main active substances in the degradation process. The superior TCH degradation performances of BWO@ND-C 3 N 4 can be ascribed to the interfacial C-O bonds and the stable built-in electric field between BWO and ND-C 3 N 4 for the fast separation of photogenerated carriers and activating PI, which can facilitate the rapid electron transfer, enhancing the TCH degradation kinetics. This work provides a broad application prospect of photocatalyst/activated PI systems for antibiotic pollution treatment in water.
Hanyu Liu,Zhuo Yu,Ming Xiao,Wenke Zhu,Junlong Liu,Lizhi Wang,Tao Xu,Wenlei Wang,Ting Yang
The efficient removal of arsenic from wastewater is still a challenge. In this paper, a heterojunction consisting of in-situ carbon-doped TiO 2 and nitrogen deficiency g-C 3 N 4 (C/TiO 2 @ND-C 3 N 4 ) has been constructed, which can completely oxidize As(III) (10,000 μg/L, 40 mL) to As(V) within 12 min under visible light and simultaneously adsorb total As (95.0%) with the pseudo-secondary kinetic equation , superior than in-situ carbon-doped TiO 2 (75.0%) and nitrogen deficiency g-C 3 N 4 (50.5%). The good photocatalytic oxidation and adsorption performances of C/TiO 2 @ND-C 3 N 4 on As(III) removal can be attributed to the successful synthesis of heterojunction. On one hand, the building of C–O–Ti interfacial chemical bonds enable rapid electron transfer and improve the efficiency of photocatalytic oxidation. On the other hand, the decreased As(V) adsorption energy resulted from the synthesized heterojunction boost the adsorption capability of As(V), which was completed by the generation of O–As bonds with oxygen-containing functional groups on the surface of TiO 2 and hydrogen bonds with high content pyrrole nitrogen derived from ND-C 3 N 4 , respectively. The results manifest that the preparation of bifunctional materials with both photocatalytic oxidation and adsorption properties provides a new strategy to achieve the removal of As.
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