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张钱新,陈平,王枫亮,曾泳钦,苏跃涵,吕文英,姚琨,刘海津,刘国光.g-C₃N₄在可见光下协同PDS降解磺胺二甲嘧啶的机制研究[J].环境科学学报,2017,37(10):3772-3779

Photocatalytic degradation mechanism of sulfamethazine using PDS/g-C₃N₄ under visible light irradiation

基金项目：国家自然科学基金（No. 21377031，21677040）；广东省自然科学基金（No.2016A030313697）；河南省教育厅项目（No.13A610528）

摘要：以二聚氰胺为前驱体合成光催化剂石墨相碳化氮（g-C₃N₄），通过透射电子显微镜（TEM）、X射线衍射（XRD）和紫外可见漫反射光谱（UV-vis DRS）等技术对g-C₃N₄材料进行形貌结构和光学性能的表征.实验过程中，以g-C₃N₄光催化降解磺胺二甲嘧啶（SMZ）中，加入过硫酸盐（PDS）联合效果的研究结果表明，PDS加快了g-C₃N₄对SMZ的光催化降解；通过荧光测试，表明了PDS使g-C₃N₄的光生空穴（h⁺）与光生电子（e^-）能够进行有效地分离，从而加强其光催化性能；实验同时研究了PDS/g-C₃N₄体系对磺胺二甲嘧啶（SMZ）光催化降解的影响机制.研究表明，SMZ的光催化降解反应符合准一级动力学规律；pH在酸性环境下有利于SMZ的降解；使用草酸钠作为光生空穴分子捕获剂，检测到h⁺存在于PDS/g-C₃N₄光催化体系中，并计算得出h⁺的贡献率为65.9%，表明h⁺在降解中起到主要作用；TOC的检测表明，加入PDS有助于SMZ的矿化.

Abstract：Graphite phase C₃N₄ (g-C₃N₄) was synthesized using dicyandiamide as the precursor. The morphology and optical properties of g-C₃N₄ were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-visible diffuse reflection (UV-vis DRS). In this study, the effect of the addition of persulfate (PDS) on the degradation of sulfamethazine (SMZ) by g-C₃N₄ photocatalytic degradation was studied. The results showed that PDS enhanced the photocatalytic degradation of SMZ by g-C₃N₄. The fluorescence test showed that PDS could effectively separate the photogenerated hole (h⁺) and photogenerated electron (e^-) from g-C₃N₄ to enhance its photocatalytic performance. The different factors of PDS/g-C₃N₄ system on the photocatalytic degradation of sulfadimidine (SMZ) was also investigated. The degradation of SMZ followed pseudo-first-order kinetics. Acidic condition is conductive to the degradation of SMZ. Quenching experiment demonstrated that h⁺ was present in the PDS/g-C₃N₄ photocatalytic system using sodium oxalate as photogenerated scavenger, and the contribution of h⁺ was calculated to be 65.9%. This result indicated the major role of h⁺ in degradation of SMZ. The detection of total organic carbon (TOC) indicated that the addition of PDS enhanced the mineralization of SMZ.