Study on release characteristics and removal of polycyclic aromatic hydrocarbons in solid waste coking sulfur paste during heating

Coking sulfur paste (CSP) is a hard-to-handle industrial solid waste. With the high sulfur content, CSP can be used to prepare asphalt modifier. This paper investigated the release characteristics of polycyclic aromatic hydrocarbons (PAHs) in CSP during heating. While heating from 42 degrees C to 480 degrees C, CSP demonstrated two weight loss stages in which certain organic compounds were evaporated from CSP. The volatiles were primarily benzene and four kinds of PAHs, including naphthalene, indene, fluorene, and phenanthrene. The total absolute release amount of volatiles increased with increase in temperature. Furthermore, to remove PAHs, CSP was sulfonated with 98% H2SO4. The optimal sulfonation conditions in the molten state of CSP were as follows: ratio of H(2)SO(4)volume to CSP mass 60 mu Lg(-1) and reaction time 60 min. At 160 degrees C, the total absolute release amount of benzene and four kinds of PAHs decreased from 14.688 x 10(3) to 0.18 mu gg(-1). Therefore, the removal of PAHs from CSP using a sulfonation agent is very effective, ensuring that CSP can be used in road engineering without pollution.