Polycyclic aromatic hydrocarbon refer to a class of organic compounds having two or more benzene. Polycyclic aromatic hydrocarbon (PAHs) are hydrocarbons containing more than two benzene rings in the molecule, including naphthalene, anthracene, phenanthrene and pyrene. Some polycyclic aromatic hydrocarbon also contain nitrogen, sulfur and cyclopentane, the wind of polycyclic aromatic hydrocarbon with carcinogenic polycyclic aromatic hydrocarbon are mostly four to six rings of fused ring compounds. The International Cancer Research Center (IARC) (1976) lists 94 carcinogenic compounds for experimental animals. Of which 15 are polycyclic aromatic hydrocarbon, benzo [a] pyrene is the first discovered environmental chemical carcinogens, and carcinogenicity is very strong, so often benzo (a) pyrene as polycyclic aromatic representative All carcinogenic polycyclic aromatic hydrocarbon 1% -20%.
The main component of polycyclic aromatic hydrocarbon
(A) anthracene, flexor, benzo (b) fluoranthene, naphthalene, acenaphthene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo (a) anthracene, Benzo (k) fluoranthene, benzo (a) pyrene, indeno (1,2,3-cd) pyrene, dibenzo (a, h) anthracene and benzo (g, h, i) perylene, - methylnone, 2-methylnone.
Removal of polycyclic aromatic hydrocarbon Conventional physical methods are heating method, coagulation sedimentation method, adsorption method, chemical method of photo-oxidation and chemical oxidation of two categories, and biochemical treatment.
Polycyclic aromatic hydrocarbon (PAHs) are volatile hydrocarbons produced by incomplete combustion of organic matter such as coal, petroleum, wood, tobacco, organic macromolecule compounds, and are important environmental and food contaminants.
Molecules contain more than two benzene ring of hydrocarbons, including naphthalene, anthracene, phenanthrene, pyrene and other 150 kinds of compounds. Some polycyclic aromatic hydrocarbon also contain nitrogen, sulfur and cyclopentane, the common carcinogenic polycyclic aromatic hydrocarbon are mostly four to six rings of fused ring compounds.
In the nature of these compounds exist biodegradation, hydrolysis, light cracking and other ways to eliminate, so that the content of the environment has always been a dynamic balance, so as to maintain a low concentration level, but in recent years, with the The intensification of human production activities undermines its dynamic balance in the environment and increases the PAHs in the environment.
Polycyclic aromatic hydrocarbon are mostly colorless or pale yellow crystals, individual with dark, high melting point and boiling point, the vapor pressure is very small, mostly insoluble in water, soluble in benzene aromatic solvents, slightly soluble in other organic In the solvent, the octanol - water partition coefficient is relatively high. Polycyclic aromatic hydrocarbon have a large conjugate system, so the solution has a certain fluorescence.