Preparation And Properties Of Coal Bitumen Based Activated Carbon And Its Composite Photocatalytic Materials

With the rapid development of industry,the types and quantities of wastewater are rapidly increasing,and solving water pollution problems has become a hot research topic,and the combined use of adsorption and photocatalysis is an effective measure for treating wastewater.Porous materials with high specific surface area,well-developed pore structure and excellent adsorption properties are widely used as adsorbents in wastewater treatment.As a novel technology to alleviate environmental problems,photocatalysis has attracted a lot of attention from researchers.Semiconductor photocatalysts TiO₂ and g-C₃N₄ have the advantages of low price,non-toxicity and high stability,but the single-component semiconductors have the disadvantages of poor absorption of visible light and easy compounding of photogenerated electron and hole pairs,which largely restrict the use of TiO₂or g-C₃N₄in photocatalysis.At present,coal tar pitch is mainly used as infrastructure material or heavy fuel oil,which not only causes waste of carbon resources,but also pollutes the environment.To address the above problems,this paper firstly prepares activated carbon,a porous material,from coal tar pitch to investigate its adsorption performance.On this basis,the composite photocatalysts were prepared by doping modification of TiO₂ and g-C₃N₄ with activated carbon as the carrier,and the photocatalytic performance of the composites was investigated.The details of the study are as follows:（1）Activated carbon（AC）was prepared using nano-ZnO as a template,coal tar pitch as a carbon source and KOH as an activator,which was characterized and used for the adsorption study of neutral red solution.The effects of AC dosage,temperature,neutral red concentration and time on the adsorption results were investigated,the adsorption kinetics and isothermal adsorption processes were mathematically fitted,and the thermodynamic parameters were calculated.The results showed that AC had a good adsorption effect on neutral red with the adsorption rate over 90%.both Langmuir and Freundlich models could be used to describe the adsorption isotherm,and the adsorption of neutral red by AC was in accordance with the quasi-secondary kinetic model with a saturation adsorption capacity of 155.521 mg/g,and the adsorption process was a spontaneous process.（2）TiO₂,TiO₂/AC,N-TiO₂/AC,Ag-TiO₂/AC and N-Ag-TiO₂/AC were prepared by sol-gel and calcination methods.The morphology and phase structure of the prepared photocatalysts were characterized,and the photocatalytic performance of different materials was investigated.The results showed that N-Ag-TiO₂/AC had better photocatalytic activity than other materials.The photocatalytic degradation of phenol was carried out using xenon lamp as the light source and the reuse of N-Ag-TiO₂/AC.The photocatalytic degradation of simulated phenol wastewater was carried out with a xenon lamp as the light source,and the reuse experiment of N-Ag-TiO₂/AC was carried out.the degradation process of phenol by N-Ag-TiO₂/AC composite photocatalyst was in accordance with the primary kinetic model,and the degradation rate could reach 96.88%with good stability and reusability.（3）g-C₃N₄,BiOCl,g-C₃N₄/BiOCl and g-C₃N₄/BiOCl/AC were synthesized by calcination and hydrothermal methods,and the morphology and phase structure of the prepared materials were characterized to study the photocatalytic properties of different materials.The photocatalytic degradation reaction was carried out by simulating wastewater with rhodamine B solution under xenon lamp irradiation,and the reuse experiment of g-C₃N₄/BiOCl/AC was carried out.g-C₃N₄/BiOCl/AC degraded rhodamine B in accordance with the primary kinetic model,and the degradation rate could reach 96.46%with good stability and reusability.