Hydrodynamic Cavitation of Creosote Oil in the Presence of a Ni2+Initiator Results in an Increase in Its Overall Naphthalene Content

Abstract

Hydrodynamic cavitation (HC) of aromatic hydrocarbons present in creosote oil obtained from coal tar in the presence of 0.3% (w/w) Ni2+ as an inducer increased its naphthalene and phenanthrene content by 7.3 and 2.6%, respectively. An optimal procedure was developed based on the use of an upstream pressure of 2.6 MPa, an immersing height (H) for the cavitator of 105 mm, 10% H2O content, use of a NiSO4 solution at pH 4.0, and an operating temperature of 75 °C. Enrichment of the naphthalene and phenanthrene components is caused by hydroxyl and hydrogen radicals generated in the reaction inducing aromatic components to undergo a series of radical demethylation/methylation reactions to produce new product ratios. The observed increases in naphthalene and phenanthrene content using Ni2+ as a radical inducer are in contrast with the previous results using Fe2+ under similar conditions, which led to the enrichment of the acenaphthalene fraction of creosote oil.