Chitosan as a Detoxicant for Oil Contaminated Soils and Its Transformations
Russian

N.G. Kasterina, A.A. Okolelova
2015 Biogeosystem Technique  
The problems of oil contaminated soils remediation are relevant due to the rapid development of the oil and gas industry. The common and most effective method of soils detoxification is sorption. We first studied a possibility of applying natural biopolymer chitosan for soils detoxification. In the scientific literature there is evidence of its use only for treatment of surface and wastewaters. Chitosan is a natural biopolymer degrading to its typical components (glucosamine,
more » ... N-acetylglucosamine) under action of ferments; it has a high sorption activity towards heavy metals. The sorbentis made of shellfish chitin. Economic efficiency of using chitosan is conditioned by the presence of a localfeedstock: wastes generated during cleaning turbines of Volzhsky Hydroelectric Power Station. Utilization of chitin containing wastes solves the environmental problem, decreases the sorbent price. High sorption efficiency of finely milled chitosan in light-chestnut clay soils is conditioned by the following: pores in the finely milled chitosan are one order less than in the soil, which allows the chitosan for mechanical holding down pollutants; the surface tension of the sorbent is less than in the clay structure; chemisorption of oil products from soils with chitosan occurs at the expense of solvation effects coming up through the formation of macromolecular complexes. High sorption efficiency of oil productswith chitosan solution in light-chestnut sandy soils is caused by the next reasons: more reactive functional groups in the chitosan solution; the solid sorbent being in contact with the contaminated sand forms a lower contact surface than the solution which envelops each contaminated sand particle increasing the contact surface. Сhitosan solution forms a film on the surface of the soil, which, if necessary, can be easily removed by mechanical means, or wakes utilized by soil microorganisms after 2-3 months. In order to prevent oil spills and their subsequent migration in the soil during the construction of petrol stations, we offer to create a sorption barrier. The barrier is a consecutive alternation of layers of large quartz sand (capacity up to 5 cm), chitosan (1 cm), river sand (5 cm), chitosan (1 cm), fine sand (5 cm), and chitosan. During the construction of small oil storage
doi:10.13187/bgt.2015.5.286 fatcat:nm4c2h725rabbn3swkmnmwaesq