The Soxhlet Extraction, Separation And Adsorption Performance Of Polyaromatic Hydrocarbons From Shenmu Coal

Energy is the foundation for the development of a country, and coal is one of the most important kinds of energy for China. However, as a primary energy source; coal is used for the power generation, industrial production and the running consumption in our country. With the development of national economy, our standards of living are also gradually improved, and people calls for a better environment. The shortcomings of coal used as the primary energy restrict its utilization.Firstly, the coal-pretreating methods and the Soxhlet extraction of these coal samples are carefully researched. The coal-pretreating methods include the acid-treatment, the swelling-treatment, the oxidant-treatment and the reductant-treatment. Then the samples are extracted by solvents such as benzene, petroleum benzine, chloroform and methyl alcohol. Through those experiments the relationship between the coal-pretreating methods and the solvent extraction rates is discovered. It is found that the Shenmu raw coal sample has the highest extraction rate among all the extraction experiments, and the Soxhlet extraction with benzene/ethanol mixed solvent has the best extraction result.Then the solvent extracts of the coal samples are enriched and analyzed with GC/MS, also 9 kinds of PAHs are quantitatively detected. Through the GC/MS analysis, the coal extracts obtained by the Soxhlet extraction can be divided into three categories, that is polycyclic aromatic hydrocarbons, aliphatic fractions and the heterocyclic compounds. Among those nine kinds of polycyclic aromatic hydrocarbons, Pyrene, Benzo[a]anthrancene, Chrysene and the Phenanthrene has a high concentration. The extracts are separated into different group compositions by column chromatography and some kinds of PAHs, such as Pyrene and Benzo[a]anthracene, are effectively enriched.In the end of this paper, Ca-A molecular sieve is used as an adsorbent for the investigation of the adsorption kinetics, isotherms and thermodynamic parameters of the polycyclic aromatic hydrocarbons. It is found that the adsorption of Pyrene onto Ca-A molecular sieve at 35℃can be rationally described by the Langmuir isotherm model and the Dubinin-Radushkevich (D-R) isotherm model.