The use of widespread and inexpensive clay minerals as adsorptive agents, as well as materials obtained by their chemical modification, can contribute to the solution of the problem of environmental pollution with antibiotics. This review considers the structural features of various natural clay minerals and the effect of these features on their sorption capacity. Based on the analysis of available papers (over the last 15 years, also including some fundamental basics over the last 20–30 years), it has been established that the main property of an antibiotic molecule affecting the ability to be adsorbed by a clay mineral is the hydrophilicity of the organic substance molecule. The leading properties that determine the ability of clays to adsorb antibiotics are the charge and area of their surfaces. The ability of antibiotic molecules to protonate and a partial change in the edge charge of mineral layers is determined by the acidity of the sorption solution. In addition, empirical evidence is provided that the most important factors affecting adsorption are the ionic strength of the sorption solution, the concentration of the adsorbent and adsorbate, and the interaction temperature. The diversity of the composition, structure, and properties of clay minerals allows them to be effective sorbents for a wide range of antibiotics.

The rapid industrial development of civilization has led to the need for the development of new materials to clean up chemically contaminated wastewater and soils. Organoclays, based on smectite minerals and various types of surfactants, are one of the most effective sorbents for adsorbing organic and inorganic pollutants. Organoclays are clay minerals that have been modified by the intercalation or grafting of organic molecules. The main mechanism of interaction between organic substances and organoclays involves the adsorption of the substances onto the surface of the clay mineral, which has an expanded structural cell. Various types of surfactants can be used to synthesize organoclays, including cationic, anionic, and amphoteric surfactants. Each type of surfactant has different properties that affect the clay’s ability to sorb. Cationic forms of trace elements, such as heavy metals, can also be adsorbed by organoclays. Data on the adsorption of these substances by organoclays are provided, along with information on how to synthesize them using various surfactants. This review also discusses the main mechanisms of interaction between these substances and clays and the various methods used to create organoclays. It is clear that the adsorption of heavy metals by organoclays is not influenced by their structure or properties, as they belong to the category of surfactant, but rather by their overall chemical structure and characteristics. The wide variety of surfactant types leads to different effects on the adsorption properties of trace elements.

For many decades, natural and modified clay minerals have been used as adsorbents to clean up aquatic and soil ecosystems contaminated with organic and inorganic pollutants. In this study, organoclays based on bentonite and various amphoteric and nonionic surfactants were synthesized and tested as effective sorbents for lead ions. The maximum values of R were obtained when describing the sorption processes using the Langmuir model, which ranged from 0.97 to 0.99. The adsorption of lead ions by these organoclays was investigated using different sorption models including the Langmuir, Freundlich, and BET. It was found that, according to the values of limiting adsorption to the Langmuir equation, the synthesized organoclays formed an increasing series: organoclay with cocamide diethanolamine < bentonite < organoclay with lauramine oxide < organoclay with sodium cocoiminodipropionate < organoclay with disodium cocoamphodiacetate < organoclay with alkyl polyglucoside. The Gibbs energy for all of the analyzed samples was calculated and found to be negative, indicating the spontaneity of the cation adsorption process in the forward direction. The maximum value of the adsorption capacity of lead cations on organoclay-based bentonite with alkyl polyglucoside was 1.49 ± 0.05 mmol/g according to the Langmuir model, and 0.523 ± 0.003 mmol/g as determined by the BET model. In the process of modifying bentonite, there was an increase in negative values of the zeta potential for organoclays compared to the initial mineral, which clearly enhanced their electrostatic interactions with the positively charged lead ions. It was hypothesized, based on the physicochemical principles, that exchange adsorption is the main mechanism for lead absorption. Based on chemical approaches, organoclays based on amphoteric surfactants absorb lead mainly through the mechanisms of electrostatic attraction, ion exchange, and complexation as well as the formation of insoluble precipitates. Organoclays based on nonionic surfactants, on the other hand, absorb lead through mechanisms of complexation (including chelation) and the formation of insoluble chemical precipitates. The comparison of isotherms from different models allows us to find the most accurate match between the model and the experimental data, and to better understand the nature of the processes involved.

The use of nature-like technologies, leading to acceleration of the processes of natural destruction of pollutants, is one of the promising directions for oil and petroleum product degradation in the environment. The joint use of oil-degrading bacteria and natural polymers with the properties of surfactants and humic acids (HAs) in bioorganic compositions is effective. In this study, humic acids from reed peat, which have a critical micelle concentration (CMC) of 0.6 g/L, were used as an organic component. Oil-degrading bacteria of the genera Rhodococcus and Pseudomonas, which have an increased biodegrading ability in relation to crude oil and waste engine oil, were used as a bacterial component. Mono- and polybacterial bioorganic compositions based on these components are proposed. The emulsification index is maximum (94% ± 2%) using a bioorganic composition based on the association of strains of three bacteria. Analysis of films of model petroleum products in vitro showed a high degree of their destruction after 7 days using monobacterial bioorganic compositions (up to 80%) and after 2 days using a bioorganic composition based on 3 strains (almost 90%). A high ability to stabilize emulsions of humic acids and develop bioorganic compositions has been established, which indicates a significant potential for their use for cleaning the environment from oil pollution. The use of a combination of humic acids and oil-degrading bacteria (all strains) makes it possible to achieve the maximum stabilizing effect of emulsions: the transmission coefficients of emulsions are 37–75% lower relative to control (oil-polluted water) and 50% lower in relation to humic acids.

This review analyzes the main methods for cleaning up oil pollution in natural ecosystems, with a particular focus on the synergy between chemical and microbiological techniques for environmental remediation. While biological methods are a green and inexpensive soil remediation technique, they have a major limitation in their inability to clean up high concentrations of toxic contaminants. The poor performance of chemical methods stems from the high cost of chemicals and concerns over their negative and toxic effects on the environment. Physical methods also have high costs due to energy consumption and the need for additional treatment of gases generated during decontamination, making them ineffective for soil remediation. The main principle of bioremediation is based on microorganisms’ ability to degrade complex organic compounds, such as petroleum. This process is described in this review. This combination of methods allows for a higher level of decontamination of soil and water ecosystems, even against pollutants that are usually resistant to degradation, such as oil derivatives. While existing methods for cleaning oil-contaminated ecosystems are highly effective, they require significant material costs to implement. Additionally, the review discusses how the joint use of current and future biotechnology techniques can lead to the development of an effective set of strategies to protect soil and water systems from oil pollution. The reviewed studies show that a hybrid biotechnological approach is the most effective remediation method. When biological decontamination methods are adopted, the optimized combination of different remediation strategies can overcome the limitations of each technique, allowing efficiencies of even more than 70% to be achieved, given that the choice still depends on the type of contaminant, its concentration, and the properties of the receiving substrate.

The study examines the antibiotic resistance of metal-tolerant bacteria isolated from the wastewater treatment plant of a large city to six antibiotics belonging to the β-lactam antibiotics, aminoglycosides and amphenicols. Resistance of bacteria from sewage sludge multitolerant to heavy metals to 18 antibiotics of the β-lactam antibiotics, tetracyclines, aminoglycosides, diaminopyrimidines, amphenicols and ansamycins was studied also. Out of 10, the metal-tolerant microorganisms isolated from wastewater treatment facilities only the Klebsiella pneumonia strain (tolerant to 3 mM Cu) from the sludge of a secondary settling tank did not show resistance to the studied antibiotics at the concentrations considered. Resistance to the maximum amount of antibiotics was typical for strains Serratia fonticola SS0-1, isolated from fresh sewage sludge and resistant to 5 mmol Cu and 3 mmol Pb, or Stenotrophomonas maltophilia SS0-5, also isolated from fresh sludge and resistant to 3 mmol Zn and Cu. It is possible that bacterial resistance to antibiotics develops not only as a result of the use of antibiotics themselves, but also as a result of environmental pollution with heavy metals, and vice versa.