Text|Small Dumb Science Popularization Bureau
Editor|Small Dumb Science Popularization Bureau
preface
With the rapid development of industrialization and urbanization, dye organic pollutants are widely present in industrial wastewater, bringing serious threats to the environment and human health.
Traditional water treatment methods have certain limitations in removing dye organic pollutants, such as low treatment efficiency, high energy consumption, and secondary pollution. Therefore, it is urgent to find an efficient, economical and environmentally friendly treatment technology.
This article aims to review the research progress of adsorption mechanism and advanced oxidation treatment method of dye organic pollutants on activated carbon fiber electrode, and discuss their application prospects.
Application of activated carbon fiber electrodes in advanced oxidation processes
Activated carbon fiber electrodes have important application value in advanced oxidation processes. Advanced oxidation is a method of degrading organic pollutants by producing highly active oxidants, including hydrogen peroxide (H2O2), ozone (O3), and chlorine dioxide (ClO2) in a highly oxidized state. Activated carbon fiber electrodes act as catalysts or electrocatalysts to promote the formation of oxidants and the degradation of organic pollutants, thereby improving the efficiency and effectiveness of advanced oxidation processes.
1. Activated carbon fiber electrode as anode catalyst
Activated carbon fiber electrodes can be used as anode catalysts to promote the formation of oxidants and the oxidation of organic pollutants. In electrochemical processes, activated carbon fiber electrodes can enhance the electrochemical production of oxidants such as hydrogen peroxide by providing electron- and surface-catalyzed active sites, and facilitate degradation reactions of organic pollutants. Activated carbon fiber electrodes can also directly participate in the degradation of organic pollutants through reactive oxygen species produced by electrolysis, such as hydroxyl radicals (•OH), superoxide radicals (•O2-), etc.
2. Activated carbon fiber electrode as an electrocatalyst
Activated carbon fiber electrodes can also be used as electrocatalysts to catalyze the oxidation of organic pollutants under the action of applied potential. By adjusting the electrode potential, activated carbon fiber electrodes can initiate the formation of oxidants and the electrocatalytic oxidation of organic pollutants. This electrocatalytic action enhances the contact between the oxidant and the organic contaminant, increasing the reaction rate and efficiency.
3. Activated carbon fiber electrode and oxidant work synergistically
Activated carbon fiber electrodes can work synergistically with oxidants to degrade organic pollutants. Activated carbon fiber electrodes adsorb organic contaminants and provide a reaction interface that makes it easier for oxidants to contact and react with organic contaminants. The activated carbon fiber electrode itself has catalytic activity, which can further promote the degradation reaction of organic pollutants.
The application of activated carbon fiber electrodes in advanced oxidation processes is mainly achieved by acting as an anode catalyst, electrocatalyst or in synergy with an oxidant. This application method can improve the degradation efficiency and rate of organic pollutants, and has potential water treatment application prospects. The design and preparation of activated carbon fiber electrodes, the selection of electrode materials and the optimization of reaction conditions still need further research and exploration to achieve more efficient and sustainable advanced oxidation treatment technologies.
Adsorption mechanism of dye organic pollutants on activated carbon fiber electrodes
1. Electrostatic effect
Dye molecules usually carry an electric charge, while activated carbon fiber electrodes have a surface charge, so electrostatic action is one of the important mechanisms of dye adsorption. When dye molecules come into contact with the electrode surface of activated carbon fibers, they interact with the charge on the electrode surface to form electrostatic adsorption. The attraction between positive and negative charges causes dye molecules to be adsorbed on the electrode surface of activated carbon fibers.
2. π-π action
Dye molecules typically have a conjugated structure in which there are overlapping clouds of π electrons between aromatic rings. The activated carbon fiber electrode surface also contains a large number of aromatic ring structures, so the dye molecules can interact with the activated carbon fiber electrode surface through π-π interaction. This mode of action can increase the adsorption strength of the dye molecules on the electrode surface.
3. Pore adsorption
Activated carbon fiber electrodes have a highly developed pore structure, including microporous and mesoporous. These pores provide a large number of adsorption sites that can adsorb dye molecules. The dye molecules diffuse within the pores of the activated carbon fiber electrodes and are trapped on the pore walls by physical adsorption. The size and distribution of the pore structure have an important influence on the adsorption performance, and larger pores can accommodate the adsorption of larger molecules.
4. Surface chemistry
The surface of the activated carbon fiber electrode has a certain chemical reactivity and can chemically react with dye molecules. The functional groups (such as hydroxyl groups, carboxyl groups, etc.) on the surface of the activated carbon fiber electrode can undergo chemical reactions such as hydrogen bonding and acid-base neutralization with the functional groups in the dye molecule, thereby enhancing the adsorption effect.
Effect of surface properties of activated carbon fiber electrodes
1. Surface charge
The charge characteristics of the electrode surface of activated carbon fiber play an important role in dye adsorption. When the electrode surface is positively or negatively charged, it can attract or repel dye molecules by electrostatic action. Positively charged surfaces are attractive to negatively charged dye molecules, and negatively charged surfaces are attractive to positively charged dye molecules. The regulation of electrode surface charge can affect the adsorption behavior of dye molecules.
2. Surface functional groups
The functional groups on the electrode surface of activated carbon fiber have an important influence on dye adsorption. Functional groups can provide adsorption sites for chemical reactions or hydrogen bonds with functional groups in dye molecules. The functional groups such as hydroxyl groups and carboxyl groups on the electrode surface of activated carbon fiber can interact with the functional groups in the dye molecules to enhance the adsorption effect.
3. Surface activity
The active site on the electrode surface of activated carbon fiber plays an important role in dye adsorption. The active site can provide a physical or chemical adsorption site that increases the chance of contact of dye molecules with the electrode surface. The presence of active sites can improve the density and adsorption capacity of the adsorption site, thereby enhancing the adsorption effect.
4. Pore structure
The pore structure of activated carbon fiber electrode has a significant influence on the adsorption performance of dye. The pore structure includes micropores and mesopores, providing a large number of adsorption sites. Larger pores can accommodate larger dye molecules, while smaller pores favor physical adsorption. The size and distribution of pore structure have an important influence on adsorption capacity and rate.
5. Surface topography
The surface morphology of activated carbon fiber electrode also has a certain influence on dye adsorption. The change of surface roughness and morphology can affect the contact area and diffusion rate of dye molecules on the electrode surface, and then affect the adsorption effect.
Development trend of dye organic pollutants
1. The development of green environmental protection dyes
With the enhancement of environmental protection awareness and the pursuit of sustainable development, the demand for green dyes has gradually increased. Green dyes usually have the characteristics of low toxicity, easy degradation and renewable, and have little impact on water and the environment. In the future, the development trend of dye organic pollutants will tend to the research and development and application of green environmental protection dyes.
2. Development of new dyes
With the continuous advancement of science and technology, the research and development and application of new dyes are also constantly advancing. New dyes may have better dyeing performance, lower pollution emissions, higher color fastness and a wider range of applications. New dyes such as functional dyes, solar response dyes, and fluorescent dyes have received more and more attention and applications in the dye industry.
3. Improvement of dye wastewater treatment technology
For the treatment of dye wastewater, traditional physicochemical methods such as adsorption, precipitation and oxidation have been widely used. The future development trend will pay more attention to the improvement and innovation of technology to improve processing efficiency and reduce processing costs. Advanced oxidation technology, electrochemical treatment technology, biodegradation technology, etc. will be more studied and applied to achieve efficient, economical and sustainable treatment of dye wastewater.
4. Application of versatility dyes
Dyes are not just used to dye fabrics, they can also have other functions. Dyes with photocatalytic activity can be used for photocatalytic reactions and photocatalytic sterilization; Dyes with fluorescent properties can be used in areas such as biomarkers and bioimaging. The future development trend will pay more attention to the versatility of dyes and expand the functional range and application fields of dyes.
The development trend of dye organic pollutants is towards green environmental protection, new dyes, improvement of wastewater treatment technology and application of multifunctional dyes. This will help improve the sustainability of the dye industry and reduce pollution to water bodies and the environment.
Application prospect of activated carbon fiber electrode in water treatment
1. Removal of dyes and organic pollutants
The activated carbon fiber electrode has good adsorption performance and can efficiently remove dye-like organic pollutants in water. By regulating the surface properties and pore structure of activated carbon fiber electrodes, efficient adsorption and removal of different types of dyes can be achieved. The activated carbon fiber electrode can also further degrade the adsorbed organic pollutants through the advanced oxidation process to improve the treatment effect.
2. Removal of heavy metal ions
Activated carbon fiber electrodes can also be used to remove heavy metal ions from water, such as lead, chromium, mercury, etc. The pore structure and surface chemistry of activated carbon fiber electrodes enable physical and chemical adsorption with heavy metal ions to remove them from water. Through electrochemical technology, electrodeposition and electroreduction of heavy metal ions can also be realized, further improving the removal efficiency.
3. Electrocatalytic degradation of organic matter in water
Activated carbon fiber electrode plays an important role as an anode catalyst in the electrocatalytic process. It can electrocatalytically degrade organic matter in water by producing oxidants such as hydroxide ions (OH-) and reactive oxygen species (such as hydroxyl radicals). This electrocatalytic degradation process has the advantages of high efficiency, controllability and selectivity, which can effectively degrade organic pollutants in water.
4. Electroadsorption and electroreduction process
Activated carbon fiber electrodes can also be applied to electroadsorption and electroreduction processes to remove dissolved substances, pigments, ions, etc. in water. By applying the appropriate potential, the electroadsorption or electroreduction of the substance can be achieved, thereby enriching or converting it from the water into a precipitable substance.
5. Water reuse
Activated carbon fiber electrodes also have potential for water reuse. Through appropriate treatment processes, useful components in wastewater can be recycled, such as the recovery of heavy metal ions, the conversion of organic matter, etc. This contributes to the efficient and sustainable use of water resources.
The author's opinion
Activated carbon fiber electrode has good application potential in the adsorption and advanced oxidation treatment of dye organic pollutants. By regulating the surface properties, pore structure and active site of activated carbon fiber electrodes, efficient adsorption and removal of dye molecules can be achieved.
The activated carbon fiber electrode can also further degrade the adsorbed organic pollutants through the advanced oxidation process to improve the treatment effect. In the field of water treatment, activated carbon fiber electrodes can also be applied to the removal of heavy metal ions, electrocatalytic degradation of organic matter in water, electroadsorption and electroreduction processes, and water resource reuse.
Although activated carbon fiber electrode has broad application prospects in water treatment, further research and improvement are still needed in practical applications. Issues such as electrode stability, cost-effectiveness, and waste disposal need to be addressed for their engineering and sustainable development. Future research directions include optimizing the design and preparation methods of activated carbon fiber electrodes, exploring the application of new active materials, and developing efficient electrochemical catalytic materials to improve the performance and application range of activated carbon fiber electrodes.
As a potential water treatment technology, activated carbon fiber electrode has important application prospects in the removal and degradation of dye organic pollutants. Through further research and development, activated carbon fiber electrodes are expected to play a greater role in practical engineering applications and contribute to the purification and protection of the water environment.
bibliography
[1] YUAN Rusheng, ZHENG Jingtang, GUAN Rongbo. Preparation of activated carbon fiber supported TiO_2 film and photocatalytic degradation of methylene blue. Fine Chemicals, 2005
XU Deping,HUANG Zhenghong,WANG Yonggang,KANG Feiyu. Three methods of carrying nano TiO_2 on activated carbon fiber cloth. Carbon Technology, 2004
[3] HUANG Zhenghong,XU Deping,KANG Feiyu,HAO Jiming. Research progress on the recombination and synergy of carbon and TiO_2 photocatalysts. New Carbon Materials, 2004
[4] WANG Jianying,HU Yongqi,ZHAO Ruihong,LI Jianjun,KANG Wentong. Preparation of activated carbon fiber and its research application in the field of environmental protection. Hebei Industrial Science and Technology, 2004
[5] Long Xiangyu, Huang Zongmai, Wu Fayuan. Application status of activated carbon fiber in water treatment. Electric Power Environmental Protection, 2004