Micro/Mesoporous Carbon Materials Prepared By Asphaltite And Its Adsorption Properties For Heavy Metal Ions

Based on rich resources of natural asphaltite mineral in China,micro-mesoporous carbon materials with higher specific surface area,bigger pore volume,and good pore structure were prepared from natural asphaltite.The effects of different preparation conditions on the surface morphology and structure of mesoporous carbon were studied,and the preparation mechanism of micro/mesoporous carbon materials was explored.The adsorption efficiency and adsorption mechanism of heavy metal Cd???in wastewater were analyzed.The main research contents can be summarized as follows:?1?The analysis of asphaltite by FT-IR,TG,GC,and GC-MS showed that the main components of asphaltite samples are alkanes,olefins,aliphatic compounds,aromatic compounds,epoxy compounds,and condensed ring aromatic hydrocarbons.The effects of anhydrous ethanol,petroleum ether,xylene,and tetrahydrofuran as solvents on the extraction rate of asphaltite were studied.The extraction rate is as high as 84.56%When xylene and petroleum ether are mixed in a ratio of 1:9.?2?The influence of different additives,carbonization temperature,carbonization time and activation temperature on the morphology,pore size and pore structure of micro/mesoporous carbon materials was carried out,and the formation process of three-dimensional mesh structure micro-mesoporous carbon materials was explored.The main formation process is mainly as follows:?a?The nano-MgO is a macroporous template;?b?Auxiliary urea decomposition and pyrolysis of asphaltite will generate a large amount of small molecule gas to form micropores?c?During the activator KOH reacted with the carbon,micropores and mesopores increased.Under the combined action of template,assistant,and activator,a three-dimensional mesh-like micro/mesoporous carbon material rich in N and O elements was formed through carbonization and activation.Under the comprehensive action of template,auxiliary,and activator,the micro-mesoporous carbon material under optimal conditions is obtained.The sample with a specific surface area of 660 m²·g^-1,a micropore specific surface area of 508 m²·g^-1,a total pore volume of 0.606 cm³·g^-1,a micropore volume of 0.252 cm³·g^-1,and a mesoporous pore volume of 0.354 cm³·g^-1,rich in N and O functional groups.The Auxiliary of the sample is urea,the carbonization time is 1 h,and the activation temperature is 1000?.?3?The adsorption performance of micro-mesoporous carbon material for Cd???in wastewater was explored.The results showed that when the pH value of the solution was 7,and the temperature was 318 K,the maximum adsorption capacity of the micro-mesoporous carbon material for Cd???in wastewater was 117.51 mg·g^-1.Studies on adsorption kinetics and adsorption equilibrium showed that the adsorption process followed the Pseudo-second-order kinetic model and the Langmuir model.The thermodynamic parameters?G⁰<0,?H⁰>0,?S⁰>0 indicated that the adsorption process was spontaneous.Cyclic adsorption experiments showed that the material had good stability and environmental friendliness.The samples U/MC_800-1-1000 before and after adsorption were analyzed by Raman,Mapping,and XPS,which proved that the heavy metal Cd???was uniformly distributed on the micro-mesoporous carbon material after adsorption,and the adsorption process was mainly chemical adsorption.