g-C_(3)N_(4)/Fe-Cu的制备以及对4-硝基苯酚光催化降解性能研究

Preparation of g-C_(3)N_(4)/Fe-Cu and research on the photocatalytic degradation properties of 4-nitrophenol

采用高温缩聚尿素和原位沉淀法制备磁性复合g-C_(3)N_(4)/Fe-Cu纳米材料,通过X-射线衍射谱(XRD)、高分辨率JEM 1200EX型透射电镜(TEM)和振动样品磁强计(VSM)对材料表面形貌、颗粒形态和结构性质进行表征。考察g-C_(3)N_(4)与Fe-Cu不同复合比1∶10、1∶5和1∶1的g-C_(3)N_(4)/Fe-Cu对4-硝基苯酚催化降解性能的影响,分析研究催化剂磁性及循环利用性,并初步探讨了降解热力学、动力学过程和降解机理。实验结果表明,此方法合成的g-C_(3)N_(4)/Fe-Cu复合材料反应活性位点丰富且分散均匀,表现出较强的催化和可循环性能。当Fe-Cu摩尔比为1∶1,g-C_(3)N_(4)与Fe-Cu质量比为1∶5时,表现出最优的活性,对4-硝基苯酚的催化性能最佳,在120 min内降解效率超过82.3%,重复循环利用3次后,降解效率仍能保持在70%以上。降解过程符合准一级动力学模型,反应活化能Ea=17.32 kJ·mol^(-1),熵变ΔS>0,ΔG<0表明降解是个熵驱动的过程,降解反应是自发进行的。

The magnetic composite g-C_(3)N_(4)/Fe-Cu nanomaterials were prepared by high-temperature polycondensation of urea and in-situ precipitation method,through X-ray diffraction spectroscopy(XRD),high-resolution JEM 1200EX transmission electron microscope(TEM)and vibrating sample magnetometer(VSM)characterize the surface morphology,particle morphology and structural properties of the material.Investigate the effect of g-C_(3)N_(4)/Fe-Cu with different compound ratios of 1∶10,1∶5 and 1∶1 of g-C_(3)N_(4) to Fe-Cu on the catalytic degradation performance of 4-nitrophenol,and analyze the catalyst Magnetism and recyclability,and preliminary discussion of degradation thermodynamics,kinetic process and degradation mechanism.The experimental results show that the g-C_(3)N_(4)/Fe-Cu composite synthesized by this method has abundant reactive sites and uniform dispersion,showing strong catalytic and recyclable performance.When the molar ratio of Fe-Cu is 1∶1 and the mass ratio of g-C_(3)N_(4) to Fe-Cu is 1∶5,it shows the best activity,and the catalytic performance of 4-nitrophenol is the best,and it degrades within 120 min.The efficiency exceeds 82.3%,and the degradation efficiency can still be maintained above 70%after repeated recycling for 3 times.The degradation process conforms to the pseudo first-order kinetic model,the activation energy of the reaction Ea=17.32 kJ·mol^(-1),the entropy changeΔS>0,andΔG<0 indicate that the degradation is an entropy-driven process,and the degradation reaction proceeds spontaneously.