g-C3N4/TiO2可见光催化降解磺胺二甲基嘧啶的研究

以商用TiO2颗粒和三聚氰胺为原料,采用高温煅烧法制备g-C3N4/TiO2复合光催化材料.利用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)、低温氮气物理吸附和紫外-可见漫反射光谱仪(UV-vis)对g-C3N4/TiO2的进行表征,并研究在可见光条件下g-C3N4/TiO2对溶液中磺胺二甲基嘧啶(Sulfamethazine,SMT)的光催化降解效果.结果表明:TiO2颗粒附着在层状结构g-C3N4/表面,形成具有孔隙结构和更大比表面积的g-C3N4/TiO2,有利于污染物的吸附.g-C3N4/TiO2的光吸收带边移动到430 nm,具有可见光响应.在可见光照射下,当g-C3N4/TiO2投加量为0.2 g/L时,初始浓度为0.5 mg/L的SMT在3h内去除率可达98.8;.在相同条件下,g-C3N4和TiO2只能分别去除57.8;和9.7;的SMT.活性物质掩蔽实验表明g-C3N4/TiO2光催化降解SMT过程中,超氧自由基(·O2-)和光生空穴(h+)在降解SMT时起主要作用.

Photocatalytic Degradation of Sulfamethazine by Using Synthesized g-C3N4/TiO2 under Visible Light

Graphitic carbon nitride/titanium dioxide (g-C3N4/TiO2)hybrid photocatalysts were synthesized by heating mixtures of commercial TiO2 particles and melamine.The g-C3N4/TiO2 samples were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),low temperature nitrogen adsorption and UV-visible diffused reflectance spectroscopy (UV-vis DRS).The photocatalytic degradation of sulfamethazine (SMT) was investigated by using g-C3N4/TiO2 under visible light.The results show that TiO2 is distribute on layered structure of g-C3N4,and form g-C3N4/TiO2 with pore structure and larger specific surface areas.The g-C3N4/TiO2 has visible light response with absorption edge of 430 nm.When the dosage of g-C3N4/TiO2 is 0.2g/L,about 98.8; of SMT in solution is removed in 3 h with an initial concentration of 0.5 mg/L under visible light,much higher than g-C3N4 (57.8;) and TiO2 (9.7;).The results of active species trapping experiments reveal that the holes (h +) and superoxide radical (· O2-) make a major contribution in photocatalytic degradation of SMT by g-C3N4/TiO2.