Complex Restoration of Oil-Contaminated Soils with New Organomineral Reagents

Abstract

Among pollutants, petroleum hydrocarbons are recognized as the priority pollutants of the environment. Petroleum hydrocarbons can cause changes in the physical and chemical properties of soils, leading to a decrease in the functional activity of the microbiota of soil biocenoses. The aim of the study was to develop ways and methods of oil-contaminated soil remediation with the new generation sorbents based on organomineral biofertilizer “Kazuglegumus” and aluminum alloys activated by indium, gallium, and tin. The structure and composition of the organomineral reagents, as well as soils with different degrees of contamination were proved by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimetry, and thermogravimetry. As a working hypothesis, it was accepted that the aluminum alloy activated by gallium, indium, and tin forms complex compounds with humic or fulvic acids, which are low-toxic or non-toxic for plants. The efficiency of cleaning oil-contaminated soils with organomineral sorbents was evaluated. The reduction of oil concentration in soil samples by 12–22% depending on the concentration of reagents and oil content in soil was revealed. The character of oil pollution impact on plants of legume families alfalfa, melilot, and sainfoin, which are characterized by the ability to accumulate and then give nitrogen to the soil, was studied. The phytotoxicity of uncontaminated and non-oil-contaminated soils was studied in laboratory and field conditions. Significantly accelerated plant growth was observed in samples of oil-contaminated soil after treatment with sorbent based on activated aluminum alloy Rau-85 and fertilizer “Kazuglegumus”. The plants had stronger root systems. These experiments are explained by the effect of Rau-85 alloys in favor of reducing the oil concentration to the normalized limits, as well as the transformation of natural humic substances and additionally applied fertilizer “Kazuglegumus” (potassium humates), which increased their biological activity.