LAYERED DOUBLE HYDROXIDES AS SORBENTS FOR THE PURIFICATION OF NATURAL WATERS FROM PETROLEUM PRODUCTS: CURRENT STATUS AND APPLICATION PROSPECTS

Abstract

The article systematizes modern achievements in the application of layered double hydroxides (LDHs) for the removal of petroleum products from natural waters. The influence of the chemical composition ([M²⁺₁₋ₓM³⁺ₓ(OH)₂]ᵡ⁺(Aⁿ⁻)ₓ/ₙ·m H₂O, де M²⁺ = Mg²⁺, Zn²⁺, Ni²⁺; M³⁺ = Al³⁺, Fe³⁺; Aⁿ⁻ = CO₃²⁻, NO₃⁻, SO₄²⁻) on the sorption capacity for different classes of petroleum products (aliphatic, aromatic, polyaromatic compounds) is analyzed. The sorption mechanisms are presented, including: interlayer anion exchange, surface adsorption, chemisorption through hydroxyl groups. Special attention is paid to modified DLHs (organoclay composites, magnetic nanocomposites), which demonstrate increased efficiency (up to 98% removal) and ease of regeneration. The prospects for creating industrial filtration systems based on SHPG for liquidation of oil spills and wastewater treatment are discussed.Pollution of aquatic ecosystems by petroleum products is a critical environmental problem due to their toxicity, resistance to biodegradation and ability to bioaccumulate.Modern environmental challenges associated with oil pollution of aquatic ecosystems necessitate the development of highly effective methods for the secondary treatment of natural waters due to the growing threat of oil pollution. Annual global oil spills exceed 8 million tons. Traditional methods (mechanical collection, coagulation) are effective only for 60–70% of pollution. Exceptional toxicity of polyaromatic hydrocarbons at concentrations > 0.01 mg/l.Traditional sorbents (activated carbon, zeolites) have limited effectiveness for emulsified forms of petroleum products. Layered double hydroxides are alternative sorption materials of a new generation for the purification of natural waters from petroleum products due to their unique combination of properties, namely: adjustable interlayer space (0.7–2.2 nm), high anion exchange capacity (up to 4 meq/g), the possibility of surface functionalization.The purpose of the scientific research is to study the use of layered double hydroxides for the sorption removal of petroleum products from natural waters, to analyze the key properties of layered double hydroxides of variable composition, which determine their effectiveness as sorbents (their adjustable chemical composition, high anion exchange capacity, ability to modify the surface). Studies of the mechanisms of sorption of petroleum products, including interlayer anion exchange, surface adsorption, chemisorption through functional groups. Evaluation of the effectiveness of different types of layered double hydroxides (Mg-Al, Zn-Al, Fe-containing) for the removal of light (gasoline) and heavy (fuel oil) fractions of petroleum products, polyaromatic hydrocarbons, emulsified forms. Determination of optimal conditions for sorption secondary purification (pH of the medium, contact time, mass of the sorbent, temperature). Analysis of promising areas for modifying layered double hydroxides to increase their effectiveness. Development of recommendations for the practical application of layered double hydroxides in industrial wastewater secondary purification systems, technologies for liquidating emergency oil spills, stationary treatment facilities. Practical significance. The results of the work can be used to improve existing water treatment methods, develop new environmentally safe sorbents, and prevent pollution of aquatic ecosystems by petroleum products.Economic and environmental benefits. Reduction of post-treatment costs by 40–60% compared to membrane methods. Possibility of using spent sorbents in road construction.