Use of Silicon Dioxide Encapsulation Method for Restoration of Oil-Polluted Soils

Abstract

Purpose. Approbation of the method of encapsulation of silicon dioxide to restore the biological value of oil-contaminated soil. Methods. The encapsulating solution was prepared using sodium silicate (7% w. / vol.) as the main component and a synthetic surfactant (sodium dodecyl sulfate). To restore the contaminated soil, a treatment solution ratio of 1:1, 1:2, 1:3 and 1:4 was used for sodium silicate and sodium dodecyl sulfate, respectively. Phytotoxicity of oil-contaminated soil was determined by biotesting aqueous extracts from the soil. Results. The most optimized for use from the studied ratios of substances is a solution consisting of 2 parts: sodium silicate and sodium dodecyl sulfate. The lowest phytotoxic effect (17%) was recorded at pH of 5 of the treated soil and the ratio of solution components 1:2 (sodium silicate / sodium dodecyl sulfate). In the experiments, 2 species of monocotyledons (oats, corn) and 2 species of dicotyledonous plants (lettuce, black radish) were used. Conclusions. The technology of encapsulation of silicon dioxide in the treatment of oil-contaminated soils with a solution of sodium silicate and sodium dodecyl sulfate is quite economically attractive. The material formed as a result of the encapsulation process dries, forming an amorphous silica material, within which, in our opinion, hydrocarbons and heavy metals accumulate, but further research is needed for such a statement.