碳氮包覆纳米Fe3O4的非自由基路径光催化去除养殖废水中四环素的机制研究
Mechanism of non-radical pathway photocatalytic removal of tetracycline from aquaculture wastewater by carbon and nitrogen coated Fe3O4 nanoparticles
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摘要: 四环素(TC)作为一种抗菌剂被广泛应用于渔业养殖中,但由于其利用率低,进入废水后未经有效处理直接排放,将造成周围水环境污染。该研究以氮化碳负载的海藻酸铁水凝胶为前驱基底,经高温煅烧衍生制备碳氮包覆的纳米磁性四氧化三铁复合材料(Fe3O4/CN),采用XRD、FT-IR和TEM等对Fe3O4/CN进行结构表征,并探究其在模拟太阳光下光催化降解水中TC的效能和机理。结果表明,当水体pH值为7,Fe3O4/CN用量为0.05 g/L,光催化反应150 min,TC(50 μmol/L)的去除率可达95.0%以上;Raman、EIS和ESR等结果表明,Fe3O4/CN缺陷程度大,电荷分离效率高;在太阳光照射下,主要通过产生空穴(h+)的非自由基路径直接氧化降解TC,且反应后的材料可通过磁铁分离回收;利用HPLC-MS检测光催化反应的中间产物,推测TC在h+作用下主要发生脱氨基、开环等氧化反应;QSAR模型预测表明中间产物毒性降低。因此,采用基于Fe3O4/CN的光催技术可以有效去除养殖废水中的TC,具有一定的潜在应用价值。
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关键词:
- 四环素 /
- 光催化 /
- 纳米四氧化三铁/碳氮 /
- 缺陷 /
- 降解路径
Abstract: Tetracycline (TC) is frequently used in fishery farming as an antibacterial agent. However, when it enters the wastewater and is discharged immediately without sufficient treatment, a low usage rate will cause pollution of the nearby water environment. This work employed high-temperature calcination derivatization to create nano-magnetic triiron tetroxide composites with carbon and nitrogen coatings (Fe3O4/CN) on an iron alginate hydrogel precursor substrate. Fe3O4/CN was structurally characterized using XRD, FT-IR, and TEM. Its effectiveness and method of photocatalytic degradation of TC in water under simulated solar light were also investigated. The results showed that the removal rate of TC (50 μmol/L) could reach more than 95.0% when the water's pH was 7, 0.05 g/L of Fe3O4/CN was added, and the photocatalytic reaction lasted 150 minutes. Results from Raman, EIS, and ESR show that Fe3O4/CN has a high charge separation efficiency and a large number of defects; Under solar radiation, TC is directly oxidized, primarily through a non-radical pathway that produces holes (h+), reactive material can be recovered by magnet separation. HPLC-MS discovered the photocatalytic reaction's intermediates, TC primarily underwent oxidation reactions such as deamidation and ring opening under the influence of h+. QSAR model prediction showed that the toxicity of the intermediates was decreased. Therefore, removing TC from agricultural wastewater using photocatalytic technology based on Fe3O4/CN has some potential application value.-
Key words:
- tetracycline /
- photocatalysis /
- Fe3O4/CN /
- defect /
- degradation path
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