硫酸根对聚合氮化碳光催化活性的影响

Effect of sulfate on photocatalytic activity of polymerized carbon nitride

在pH=1条件下分别加入硫酸根、硝酸根、磷酸根对三聚氰胺进行处理,采用高温煅烧法制备了一系列聚合氮化碳材料,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)等分析手段对样品进行了表征。以罗丹明B(RhB)为污染物,探究了在可见光下聚合氮化碳对RhB的光催化降解性能、稳定性以及降解机理。加入0.12 mol硫酸根处理的聚合氮化碳(CN-0.04SO_(4)^(2-))在45 min内对RhB的降解率为99.1%,其伪一级动力学常数是未加硫酸根的23.0倍,硫酸根能有效地增强聚合氮化碳的光催化活性。CN-0.04SO_(4)^(2-)经过3次循环实验对RhB的降解率略有下降,说明其具有良好的稳定性。活性物种捕获实验表明,影响光催化降解RhB的主要活性物种是·O_(2)^(-)和·OH。

A series of polymerized carbon nitride were prepared by high temperature calcination method after the treatment of melamine with adding SO_(4)^(2-),NO_(3)^(-)and PO_(4)^(3-)under the condition of pH=1,respectively.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),UV-Visible diffuse reflectance spectroscopy(UV-Vis DRS),etc.Using rhodamine B(RhB)as pollutant,the photocatalytic degradation activity,stability and degradation mechanism of polymerized carbon nitride were explored under visible light.The degradation of RhB by polymerized carbon nitride(CN-0.04SO_(4)^(2-))with 0.12 mol SO_(4)^(2-)was 99.1%within 45 min,and its pseudo-first-order kinetic constant was 23.0 times greater than that of no SO_(4)^(2-).SO_(4)^(2-),which could effectively enhance the photocatalytic activity of polymerized carbon nitride.The degradation of CN-0.04SO_(4)^(2-)was decreased slightly after three cycles,indicating that it had good stability.Active species capture experiment showed that·O_(2)^(-)and·OH were the main active species affecting photocatalytic degradation of RhB.