Formation And Mechanism Of Oil-suspended Particulate Matter Aggregates In Coastal Environment

With the development of the petroleum industry and the petroleum transportation industry,oil spills in the coastal environment frequently occur,causing serious harm to the local economy and the environment.Naturally occurring particulate matter forms oil-suspended particulate matter aggregates(OSAs)with oil spills under ocean hydrodynamic conditions.The formation of aggregates promotes the dispersion of oil droplets and increases oil droplets and microorganisms.The contact area is thus more conducive to the degradation and removal of oil spills.In this paper,3# natural soil,kaolin and bentonite are selected as the particulate matter in the intertidal zone of the Yellow River Mouth.Different types of petroleum and natural seawater are used as the reaction medium.The constant temperature oscillation box is used to simulate the ocean wave environment and study under different marine environment conditions.Mechanisms and characteristics of oil-suspended particle agglomerates(aggregate structure characteristics,aggregate size and chemical composition).The experiment mainly studied the modification of particulate matter,and investigated the composition and physical and chemical properties of representative suspended particulate matter and oil;the effect of different suspended particulate matter concentration and particle size on the degradation characteristics of oil spill.The experimental results show that:(1)After adding modified suspended solids such as CTAB-bentonite,Bent-bentonite,DMSO-kaolin and CTAB-natural soil,the interfacial tension of oil-water is greatly reduced,and the absolute value of zeta potential of emulsion is significantly reduced;(2)With the increase of the concentration of particulate matter,the interfacial tension of oil-water gradually decreases and the absolute value of the zeta potential of the emulsion decreases;the added microorganisms can reduce the interfacial tension of oilwater and reduce the absolute value of the zeta potential of the emulsion;(3)For the same oil,the microbial degradation ability is N3>N1>N4>N2;for the same kind of microorganism,its ability to degrade different types of oil is 0#diesel>Venezuela crude>Jibei crude.The oil removal efficiency of the modified particulate matter forming aggregates is consistent with that before unmodified,and both are bentonite>natural soil>kaolin.Moreover,the oil removal efficiency of the modified particulate matter forming aggregates is obviously improved compared with that before modification,and the bentonite can be increased from 36.1% to49.2%.As the concentration of particulate matter increases and the particle size decreases,the number of aggregates formed gradually increases and the particle size gradually decreases.When the particles interact with the microorganisms,the oil removal rate is significantly higher than that of the particulate matter and the microorganisms alone,and the N3 and the combined oil spill clearance rate can reach 85.6%;(4)Under the action of microorganisms,the components of carbon content of 0# diesel and Venezuelan crude oil between C8～C12disappeared,and the peaks shifted to the right;after the addition of particulate matter,the abundance of petroleum components decreased significantly.The proportion of alkane and aromatic hydrocarbons is gradually decreasing,while the proportion of hydrocarbon derivatives is gradually increasing.