Degradation Of Organic Compounds By Activating Persulfate Over Copper And Cobalt Doped Two-Dimensional Materials

The refractory organic pollutants discharged from industrial production seriously affect the ecological environment.As typical organic pollutants in wastewater,dyes need to be degraded by advanced oxidation technology.Among them,photocatalytic technology uses clean energy to realize environmentally friendly oxidation degradation,and has high application value.However,the photogenerated carriers are easy to recombine and the catalytic efficiency is low.Therefore,it is necessary to develop highly active catalysts and to integrate other advanced oxidation technologies to improve catalytic capacity.In order to solve the above problems,dye was taken as model pollutant,Visible light catalytic fuel cell（vis-PFC）and advanced oxidation coupling system（vis-PMS-PFC）based on the activation of peroximonosulfate（PMS）were constructed in this paper.The catalytic performance of the system was investigated by using cobalt（Co）supported molybdenum sulfide（Mo S₂）as catalytic electrode;A Cu-Co bimetal co-doped carbon nitride nanocomposite（Cu Co-g-C₃N₄）was synthesized and applied to the visible light（vis）co-activation of PMS advanced oxidation system（vis-PMS）.（1）The 1T/2H mixed phase Co_0.75Mo₃S_3.75/Mo S₂ nanometer composite catalytic electrode was prepared by hydrothermal method as the photoanode of vis-PMS-PFC coupling system.Rhodamine B（Rh B）dye was selected as the mode pollutant for catalytic degradation,which extended the catalytic oxidation limited to the surrounding of composite materials to the whole system free radical chain reaction.The composites were characterized by High resolution Transmission Electron microscopy（TEM）and X-ray photoelectron spectroscopy（XPS）and other techniques.The results show that Co_0.75Mo₃S_3.75/Mo S₂exists as Co Mo S mixed phase,and it has a typical two-dimensional lamellar structure.The surface-loaded metal cobalt atoms are uniformly dispersed,which can provide a large number of catalytic active sites.The visible light absorption performance is good,the electron transfer ability is strong,and it is suitable for use as an electrode material.Through the screening of composite materials with different cobalt doping ratios,it is found that the catalytic effect is the best when the actual loading of Co is 1 wt%.The influencing factors of the system were investigated by optimizing the reaction conditions.The results showed that when the stainless steel mesh was coated with 0.3 g·L^-1 of 1 wt%Co_0.75Mo₃S_3.75/Mo S₂,at p H 6.5,the external 50W halogen tungsten lamp provided the visible light source and 100Ωexternal resistance was connected in series to activate 0.06 m M PMS,98%of Rh B with an initial concentration of 50mg·L^-1 can be removed within 21 minutes,and the reaction kinetic constant reached 0.261min^-1.（2）Two-dimensional Cu Co-g-C₃N₄ bimetallic supported catalytic material was prepared by calcination method,and PMS was activated in coordination with visible light.The performance in catalytic degradation of Rh B as a model pollutant was investigated.Scanning electron microscope（SEM）and XPS characterizations show that the surface of Cu Co-g-C₃N₄has a low content of copper and cobalt,and both metal atoms exist in the form of polyvalent ions,which contributes to the cyclic activation of oxidants.Diffuse reflectance spectroscopy shows that the composite has good response in visible light range.Upon activation by light and catalyst of PMS,reactive oxidative species are rapidly produced and that degrade or decompose pollutant.By changing the reaction conditions such as metal doping ratio,reaction system and PMS concentration,the optimal experimental environment was explored.The results showed that under neutral environment,50 W visible light irradiation assisted 1.0g·L^-11:1 Cu Co-g-C₃N₄ to activate 0.08 m M PMS,and 99.8%of Rh B with an initial concentration of 50 mg·L^-1 was removed within 5 minutes,and the corresponding k value reached the maximum value is 2.542 min^-1,and the catalytic material has high stability and reusable performance.For the first time,copper-cobalt bimetal supported two-dimensional materials were used to synergistically activate PMS,which provides a new idea for material modification applied to advanced oxidation.