褐煤基活性炭制备研究进展

Research progress in preparation of lignite based activated carbon

褐煤资源丰富,价格低廉,褐煤孔隙较多,官能团丰富,酚羟基为主,具有反应活性高,活化时间短等特点,基于褐煤性质的优势,褐煤制备活性炭备受关注。褐煤基活性炭广泛应用于工业气体净化、废水处理、煤基电极和超级电容器。由于褐煤发热量低,污染物排放高,因此褐煤制备高附加值活性炭应用具有重要意义。活性炭孔结构、比表面积和孔径分布是制约褐煤基活性炭发展的关键。为增强活性炭的吸附能力采用不同制备方法调控孔结构。综述了褐煤性质和褐煤基活性炭性质的主要影响因素,包括原料、配煤、褐煤成型条件。总结了褐煤制备活性炭的方法包括化学法(盐酸、磷酸、氢氧化钾)、物理法(水蒸气、二氧化碳和烟道气)和物理化学法(化学气体联合活化和微波辅助化学活化),阐述了不同制备方法的褐煤活性炭机理。针对褐煤活性炭制备方法存在的问题进行展望。

Lignite has rich resources,low price,many pores,rich functional groups,mainly phenolic hydroxyl,high reaction activity,short activation time and other characteristics.Based on the advantages of lignite properties,the preparation of activated carbon from lig⁃nite has attracted much attention.Lignite based activated carbon is widely used in industrial gas purification,wastewater treatment,coal based electrode and supercapacitor.As lignite has low calorific value and high pollutant emission,it is of great significance to prepare high value-added activated carbon from lignite.The pore structure,specific surface area and pore size distribution of activated carbon restrict the development of lignite based activated carbon.In order to enhance the adsorption capacity of activated carbon,different prepara⁃tion methods were used to adjust the pore structure.The properties of lignite and the main factors affecting the properties of lignite based activated carbon,including raw materials,coal blending and lignite briquetting conditions,are reviewed.The preparation methods of acti⁃vated carbon from lignite include chemical method(hydrochloric acid,phosphoric acid,potassium hydroxide),physical method(steam,carbon dioxide and flue gas)and physical chemical method(chemical gas combined activation and microwave assisted chemical activation).The mechanism of different preparation methods of lignite activated carbon was described.The problems in preparation of acti⁃vated carbon from lignite were prospected.