Development of biocarbon sorbent from corn waste with increased destructive activity in relation to oil

Abstract

The object of research is the created bioactive sorbent based on biochar from corn waste for the purification of oil-contaminated natural environments. The expediency of using biochar from corn cobs as a matrix – a carrier of microorganisms-destructors of petroleum hydrocarbons in the production of biosorbent – has been substantiated. Biochar meets the requirements for oil sorbents – environmental friendliness, oil resistance (6–8 g of oil per 1 g of sorbent), manufacturability and biocompatibility. The porous structure and chemical nature of the surface partly determines the absorbency of the material, but the dominant factor is the interaction of the hydrophobic surface with petroleum hydrocarbons. A universal oil oxidizer – a microbial complex isolated from oil-polluted natural objects, in combination with a carbon carrier, is capable of neutralizing oil pollution of various types and concentrations. It has been established that microorganisms – oil-destructors, immobilized on the surface of the sorbent, are capable of decomposing almost all oil hydrocarbons. Microorganisms immobilized on a carbon material have a great potential for destructive action. During immobilization, the viability of microbial cells is maintained, and the effect of their use is significantly increased. The use of a bioactive carbon sorbent based on biochar and immobilized natural oil-oxidizing microorganisms of a wide spectrum of action allows one to localize oil pollution and neutralize it through biodegradation. The optimal parameters for obtaining an oleophilic sorption matrix based on biochar from corn waste and for growing microbial biomass with a high destructive activity for oil hydrocarbons have been established. The optimum pyrolysis temperature is 300–350 °С, the pyrolysis time is 25–30 minutes. In this case, the sorption of oil obtained biochar reaches maximum values (6–8 g oil/gsorbent). Sufficient number of immobilized microorganisms – oil destructors 120–200·104 cells for active decomposition of oil localized on the sorbent surface. The operational characteristics of the obtained bioactive sorbents, technological features and methods of their use in cleaning the environment from oil pollution have been studied. The biosorbent does not require removal from the places of use and disposal. Cleaning of soils contaminated with oil and oil products has specific features and requires the use of agricultural techniques (loosening, moistening). The studies carried out have shown a change in the concentration of oil pollution in the soil from 40 % to 1–5 % of oil in the process of biodegradation after 3 months at positive temperatures.