纳米g-C_3N_4/Fe-Cu可见光催化降解甲基橙的研究

Photocatalytic Degradation of Methyl Orange with g-C_3N_4/Fe-Cu

该文采用高温缩聚尿素和液相还原铁盐铜盐的方法制备了g-C_3N_4负载的纳米Fe/Cu复合材料,通过X射线衍射分析仪(XRD)、透射电镜(TEM)对其进行了表征,研究了复合材料对甲基橙的催化去除。实验结果表明,纳米g-C_3N_4片可见光催化和零价Fe/Cu双金属催化技术的结合,能够协同促进复合材料对溶液中甲基橙污染物的高效去除。在常温常压,pH=4.0下,g-C_3N_4负载的纳米Fe/Cu复合材料对甲基橙的最大去除量可达到300.5 mg/g,随着反应的进行,溶液p H值增加,g-C_3N_4/Fe-Cu复合材料反应活性降低。一定范围内(CrO_4^(2-)浓度在0~3 mg/L),六价铬离子的存在,促进了纳米g-C_3N_4/Fe-Cu对甲基橙的去除,随着CrO_4^(2-)离子浓度的增加,甲基橙的去除率有缓慢的增加。

In this paper, g-C_3N_4 supported nano-Fe/Cu composites were prepared by high-temperature polycondensation of urea and liquid-phase reduction of iron salts and copper salts. The nano-Fe/Cu composites were characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM). The catalytic removal of methyl orange from composite ma-terials was studied. The experimental results show that the combination of nano-g-C_3N_4 visible light photocatalytic and zerovalent Fe/Cu bimetallic catalysis can synergistically promote the efficient removal of methyl orange pollutant from the com-posite. The maximum removal of methyl orange by g-C_3N_4 nano-Fe/Cu composite was 300.5 mg/g at room temperature and normal pressure, pH = 4.0. As the reaction progressed, the p H value of the solution increased and the molar ratio of g-C_3N_4/Fe-Cu composite materials decreased reactivity. The removal of methyl orange by g-C_3N_4/Fe-Cu.nano-g-C_3N_4/Fe-Cu was promoted by the presence of hexavalent chromium ions in a certain range(CrO_4^(2-)concentration 0~3 mg/L). With the increase of CrO_4^(2-)concentration, methyl orange removal rate increased slowly. The kinetic model of this process was simulated. It was found that the photocatalytic degradation of methyl orange by nanometer g-C_3N_4/Fe-Cu was more in accordance with quasifirst-order kinetic model. The degradation rate of methyl orange was proportional to the logarithm of initial concentration.