Study On Vertical Migration And Desorption Regulation Of Crude Oil In Sandy Beach

Oil pollutants has been mainly the one of pollutants in the coastal ocean．So ithas important scientific value for oil contamination control and remediation to studymigration、 penetration and desorption regulation of oil contaminants insands．Through the conical flask experiment in this paper，the static adsorption anddesorption law on sands are measured．The effect of biodiesel on crude oil desorptionwith different kinds、dosage and dosing methods are also tested；Through the sandcolumn experiment，crude oil migration and penetration law in sandy beaches and thedynamic desorption process are studied．The following conclusions：（1）The adsorption kinetic curve of crude oil on sands follows the Lagergren-Pseudo-first-order kinetic moder，and the adsorption capacity of crude oil increaseswith the decrease of particle size and pH，and with increment the salinity．（2）The height of clean sands is1000mm in sand column．Leaching with oilywater，the oil concentration in water declines from5.00mg/L to0.50mg/L in the firstday，then keep low．This indicate that the migration rate of crude oil is very slow，and the crude oil pollutants are mainly gathered in the25cm upper layer．90%ofcrude oil are retained by sands．（3）In crude oil penetration test，the thickness of crude oil in sands surface is3cm and10cm in sand column，and the infiltration distance is14cm and40cm in thefirst day．Then the infiltration rate of crude oil is getting slower and slower with theinfiltration time．The3cm of crude oil thickness stop infiltration in the second day，and the most distance is19cm．The10cm of crude oil thickness stop infiltration in theten day，and the most distance is90cm．So the more the amount of crude oil，thedeeper the penetration distance．（4）Through the conical flask experiments，the adsorption kinetic curves ofcrude oil on sands have been proven to follow the Lagergren-pesudo-second-orderkinetic mode．The desorption capacity of crude oil decreases with the increase ofsalinity and pH，and with the decrease of vibrant frequency．Biodiesel has asignificant role in promoting oil desorption from the sands．Different kinds of biodiesel have different capacity．Under the experiment condition，the desorptioncapacity from low to high is cooking oil biodiesel（5.42mg/g），palm biodiesel（6.56mg/g），and rapeseed biodiesel（7.34mg/g）．The desorption capacity of oilfrom the sands increase with the dosage of biodiesel．（5）The height of contaminated sands is20cm in sand column．during the oildynamic continuous adsorption oil concentration in water out of the sand columulower fall quickly at the beginning of the test and decrease slowly in2h，theconcentration of crude oil tends to balance after about65h．After the test，the oilconcentration in sands do not have much difference at different depths，8.78%of thecrude oil can be removed．Pollution intensity of the sands have little effect on oildesorption process，and the more crude oil in the sands，the greater oil concentrationin water．Height of water does not affect the oil desorption process，and theconcentration of oil desorption have some differences and increases with theincrement of water height．（6）Biodiesel promotes the desorption of oil from the sands and mades oilrelease capacity and oil concentration in water out of the sand columu lowerincrease．50.5%of the crude oil can be removed from the sands．It is higher than thatwithout biodiesel．The experiment also obtain that the best dosage of biodiesel is2times the column of crude oil in contaminated sand．...