Effect Of Dispersant On Polycyclic Aromatic Hydrocarbons Content In Submerged Oil

In recent years,the phenomenon of unknown source oil landed in the Bohai Sea is occured.It is due to the sinking of oil spill is happened in the past spill accident.Sunken and submerged oil will do great harm to the marine environment,aquaculture and tourism.The submerged oil at the bottom of the bed will be buried by sediment,and it is difficult to be monitored and cleared,toxic components in the submerged oil,especially polycyclic aromatic hydrocarbons,can cause long-term harm to the environment.The formation mechanism of the sunken and submerged oil is complex,currently less relevant research.The research showed that oil will interact with suspended particulate matter to form oil-suspended particulate matter aggregates,and then settle to the bottom to form submerged oil.In this study,the indoor conical flask batch test was conducted with 380#fuel oil,Merey crude oil and Oman crude oil as test oil.Quartz,sand and silt were used as test particles,GM-2 and WP were selected,a reciprocating oscillator was used to oscillate the oil and particulate matter under certain mixing conditions and separate the submerged oil.After extraction and concentration,the content of polycyclic aromatic hydrocarbons in the submerged oil was determined by gas chromatography-mass spectrometry(GC-MS).The equilibrium time and the optimal concentration of particulate matter were screened by pre-experiment,and the effect of dispersant on the content of polycyclic aromatic hydrocarbons in the submerged oil was studied.Results show that:(1)In the submerged oil,the content of low molecular weight compounds with low benzene ring number is higher,while the content of high molecular weight compound with high benzene ring number is relatively low;(2)As the oscillation time increases,the content of polycyclic aromatic hydrocarbons in the Submerged oil increases first and then stabilizes,due to the high hydrophobicity of the four to six-ring high molecular weight compounds,there is no significant change in the content of the submerged oil,so its relative content is reduced,while the relative content of low molecular weight compounds increases;(3)The increase of particulate matter concentration is conducive to the formation of oil-suspended particulate aggregates,but as the concentration of particulate matter increases,the content of polycyclic aromatic hydrocarbons in the submerged oil increases first and then decreases,indicating that excessive concentration of particulate matter will weaken the formation of submerged oil;(4)Dispersant can promote the formation of the submerged oil and increase the dissolution of high-cyclic PAHs,but excessive use will also inhibit the production of the submerged oil.In general,the promotion effect of WP is better than that of GM-2.