Results of experimental studies and the current scientific context regarding glauconite as a natural pesticide sorbent
Y. Kozub
The use of pesticides has significantly boosted agricultural productivity; however, it has simultaneously presented society with another challenge: what happens to these chemical substances after application, prolonged storage, or their entry into the soil?
The situation is particularly complex at sites where unusable or banned pesticides were formerly stored. Even after the chemicals themselves have been removed, the soil can remain a source of secondary contamination. Residual substances interact with the soil solution, migrate with water, and—under certain conditions—can enter surface and groundwater.
Our research indicated that residual pesticide concentrations at long-term storage sites could exceed maximum permissible levels by 10 to 20 times. The potential for further contaminant migration was a key factor driving the search for an accessible natural sorbent.
Glauconite emerged as one such material.
Why glauconite?
Glauconite-bearing rocks are of interest because they consist of a natural mineral material with an active surface capable of interacting with various substances in an aqueous environment.
Current scientific literature confirms that natural clay minerals and phyllosilicates are capable of sorbing organic pollutants, including pesticides. The underlying mechanisms may involve surface adsorption, hydrogen and coordination bonding, electrostatic interactions, hydrophobic associations, and—in the case of charged molecules—ion exchange. Efficiency depends significantly on both the nature of the sorbent and the chemical properties of the specific pesticide. (MDPI)
For this reason, experimental testing is required to evaluate the practical suitability of natural glauconite raw material.
Materials and methods of the study
For the experiments, unbeneficiated and non-activated quartz-glauconite sands from the “Adamivka II” deposit were used; these contained up to 40% glauconite and had a particle size of less than 0.5 mm.
This is a significant feature of the study. The material investigated was not a laboratory-synthesized sorbent or a chemically modified concentrate, but a natural glauconite-bearing rock.
Model aqueous solutions were prepared for nine test substances:
DDT, HCH, Tilt, Baytan, Chlorophos, DDVP, Actellic, Decis, and Cymbush.
Glauconite rock (10, 50, or 100 g, respectively) was added to 1000 ml of the model solution. After five minutes of stirring, the system was allowed to settle for 24 hours, after which residual pesticide concentrations were determined. Analysis was performed at the toxicology laboratory of the Lviv Regional Sanitary-Epidemiological Station using a “Kristall-2000” chromatograph.
Important editorial clarification
In the original table, the variants were designated as 1%, 5%, and 10% glauconite. However, in accordance with the described methodology, the actual amounts added were 10, 50, and 100 g of glauconite rock per liter of solution.
Therefore, in the current version of the paper, it is scientifically more precise to indicate both values:
Table 1. What has been confirmed by research on glauconite to date
| Designations in the original work | Quantity of glauconitic rock | Solid-to-solution ratio |
|---|---|---|
| 1% | 10 g/L | 10 g : 1000 ml |
| 5% | 50 g/L | 50 g : 1000 ml |
| 10% | 100 g/L | 100 g : 1000 ml |
This does not mean that 10, 50, or 100 g of pure glauconite was added to the solution; the natural raw material itself contained up to 40% glauconite.
This clarification is particularly important for the future comparison of our results with international studies.
What did the experiment show?
The results revealed widely differing behavior of the substances under study.
Table 1. Change in pesticide concentration after contact with glauconite rock
| Preparation | Initial concentration, mg/L | 10 g/L: residue, mg/L | Absorption, % | 50 g/L: residue, mg/L | Absorption, % | 100 g/L: residue, mg/L | Absorption, % |
|---|---|---|---|---|---|---|---|
| DDT | 0,008 | 0 | 100 | 0 | 100 | 0 | 100 |
| HCH | 0,040 | 0,024 | 40 | 0,024 | 40 | 0,012 | 70 |
| TILT | 0,060 | 0,040 | 33 | 0,024 | 60 | 0,020 | 67 |
| Baitan | 0,080 | 0,060 | 25 | 0,048 | 40 | 0,040 | 50 |
| Chlorophos | 0,010 | 0,007 | 30 | 0,005 | 50 | 0 | 100 |
| DDVF | 0,010 | 0 | 100 | 0 | 100 | 0 | 100 |
| Actellic | 0,040 | 0,032 | 20 | 0,020 | 50 | 0,012 | 70 |
| Decis | 0,032 | 0,012 | 63 | 0,006 | 81 | 0,004 | 88 |
| Tsymbush | 0,004 | 0,002 | 50 | 0 | 100 | 0 | 100 |
Source: original experimental data of Yu.B. Kozub and Yu.I. Fedoryshyn.
The table itself demonstrates that the glauconite material does not act on all substances in the same way. For some substances, virtually complete removal is observed even at the lowest tested quantity of the sorbent; for others, a gradual increase in sorption occurs as the solid-to-liquid ratio increases.
To maintain continuity with the original study, the results are presented below in three groups of graphs. However, these groups should not be regarded as a modern, formal chemical classification of all the preparations; some of the names used in the original study are trade names for historical formulations.
Fig. 1. Sorption of DDT, HCH, and Tilt depending on the amount of glauconite rock.
Sorption of DDT, HCH, and Tilt
Uptake fraction after 24-hour contact with glauconite rock
Source: experimental data by Yu.B. Kozub and Yu.I. Fedoryshyn.
DDT stands out in particular. In the model experiment, after contact with as little as 10 g of the material per liter, its concentration fell below the limit of detection—which, in the original study, corresponds to 100% uptake. The result for HCH was different: 40% at 10 and 50 g/L, and 70% at 100 g/L. Tilt showed a progressive increase: 33%, 60%, and 67%.
This difference is fundamentally important. It demonstrates that the term “pesticide sorption by glauconite” should not be viewed as a single, universal value. Each molecule interacts with the mineral surface in its own way.
Fig. 2. Sorption of Baytan, Chlorophos, and DDVP.
Sorption of Baytan, Chlorophos, and DDVP
Uptake fraction after 24-hour contact with glauconite rock
Source: experimental data by Yu.B. Kozub and Yu.I. Fedoryshyn.
DDVP once again demonstrates a maximum result even at the lowest ratio tested. Chlorophos behaves differently: its uptake efficiency rises from 30% to 50%, reaching 100% at a ratio of 100 g of material per liter. Baytan shows a more gradual trend—25%, 40%, and 50%.
This may indicate varying molecular affinities for available surface sites, differing sorption kinetics, and distinct interaction mechanisms. However, it is premature to determine the specific mechanism based solely on these results; doing so would require sorption isotherms, structural surface analyses, and the variation of physicochemical conditions.
Fig. 3. Sorption of Actellic, Decis, and Cymbush.
Sorption of Actellic, Decis, and Cimbush
Proportion of uptake after 24-hour contact with glauconite rock
Source: experimental data by Yu.B. Kozub and Yu.I. Fedoryshyn.
Tsymbush is of particular interest here: increasing the dosage from 10 to 50 g/L resulted in an increase in uptake from 50% to 100%. For Decis, an uptake of 63% was observed at just 10 g/L, with subsequent figures rising to 81% and 88%. Actellic demonstrated a virtually consistent dose-response relationship: 20%, 50%, and 70%.
Three different types of behavior
If we examine these nine substances not in terms of their formal classification but rather based on the nature of the experimental response, an interesting pattern emerges.
The first type comprises substances for which a high result was achieved even with the minimum quantity of rock tested; DDT and DDVF are the most striking examples.
The second type involves a gradual, dose-dependent response. This pattern was observed with HCH, Tilt, Baytan, Actellic, and Decis: increasing the amount of glauconite rock generally led to an increase in the proportion of the substance adsorbed.
A third, interesting pattern is a sharp increase occurring once a specific ratio of sorbent to solution is reached; this is the pattern observed with Chlorophos and Cimbush.
This is one reason why the experimental results should not be reduced to a single, averaged figure representing “glauconite efficiency.” The sorption profile of each pollutant provides far more informative data.
Do these results align with modern international science?
In general, yes, but with important caveats.
A comprehensive review by Cornejo, Celis, Pavlovic, and Ulibarri, published in *Clay Minerals*, shows that natural layered minerals have long been considered potential sorbents for pesticides. The authors highlight the importance of high specific surface area and the potential for surface modification to enhance affinity for specific organic molecules. (Cambridge University Press)
A 2021 review by Masini and Abate clarifies this picture. Natural clays are particularly effective for certain charged organic molecules, whereas for neutral and hydrophobic pesticides, the outcome depends significantly on the nature of the surface. The authors identify electrostatic interactions, hydrogen and coordination bonding, surface complexation, and hydrophobic interactions as the primary potential mechanisms. (MDPI)
Thus, the variation in sorption levels—ranging from 20% to 50% and 100% for different substances in our experiment—is not surprising; rather, it is to be expected from the perspective of modern surface physical chemistry.
The mineral surface matters even for hydrophobic pesticides.
The study by Oudou and Hansen published in *Chemosphere* is particularly interesting for comparison. The authors investigated the sorption of four pyrethroids—lambda-cyhalothrin, cypermethrin, deltamethrin, and fenvalerate—onto quartz, corundum, kaolinite, and montmorillonite.
Sorption occurred on all the mineral surfaces studied, with the affinity depending on both the specific mineral and the pyrethroid itself. The authors specifically highlighted the importance of mineral surfaces in subsoils and aquifers characterized by low organic matter content. (University of Copenhagen Research Portal)
This aligns well with the general rationale of our experiments: even without organic modification, natural mineral material can significantly influence the mobility of organic pollutants.
At the same time, another study on cypermethrin demonstrated that coating a mineral surface with humic substances can substantially increase sorption, with the organic component of the particles playing a dominant role. (ScienceDirect)
This is a crucial point regarding actual soil: in a real soil environment, glauconite does not interact in isolation but rather in conjunction with humus, iron oxides, other minerals, and microorganisms.
The influence of the soil can be no less significant than the influence of the pesticide itself.
This is clearly illustrated by the example of propiconazole.
International studies have shown that its sorption varies significantly depending on soil properties. In ten acidic vineyard soils, organic matter and amorphous iron oxides played a key role. (ScienceDirect)
In another study involving five soils, propiconazole sorption coefficients varied more than tenfold and were correlated with pH; the presence of a second fungicide also altered sorption and mobility. (PubMed)
Therefore, when moving from our model solution to field soil, one cannot expect a figure—such as 67%—to automatically remain the same.
On the contrary, this figure serves as an initial experimental data point, after which the “pesticide–mineral–water–organic matter–pH–competing ions” system must be investigated.
Chlorophos: a particularly interesting confirmation from modern literature
One of the most interesting results of our experiment was the variation in Chlorophos uptake: from 30% at a rock concentration of 10 g/L to 50% at 50 g/L, and up to 100% at 100 g/L.
Years after our work was conducted, a specialized study on the adsorption of trichlorfon onto phyllosilicate minerals—and the influence of low-molecular-weight organic acids on this process—was published in the journal *Pedosphere*.
This is particularly noteworthy because *Pedosphere* is indexed in Scopus and Web of Science, and the experimental design itself accounts for the more complex chemistry characteristic of soil and rhizosphere environments.
Thus, the line of inquiry we originally pursued using natural glauconite rock is now being continued at a significantly more advanced level within the international research community.
Sorption and degradation are not the same thing.
This is arguably the most important clarification regarding the practical application of the results.
If the concentration of a substance in an aqueous solution decreases after contact with a sorbent, it implies that a portion of the substance has transferred from the aqueous phase to the solid phase or has become undetectable by the analytical method employed.
However, this does not in itself prove the chemical degradation of the molecule.
A sorbed pesticide may remain on the surface, transition into a more strongly bound state, gradually desorb, or undergo further biological or abiotic degradation.
For instance, a study on pirimiphos-methyl in soil-water systems demonstrated that sorption and abiotic degradation can occur simultaneously. Within just the first ten minutes, approximately 37% and 41% of the initial amount of the substance were sorbed in the two soils studied. (ACS Publications)
Simultaneous time-dependent sorption and microbiological degradation have also been demonstrated for propiconazole. (ScienceDirect)
Therefore, modern remediation technology must address not only the question:
“How much of the pollutant has disappeared from the aqueous phase?”
but also the following:
“What happened to it after sorption?”
What can we assert based on our own research?
Three points can be stated with a reasonable degree of certainty.
First, under the conditions of the conducted model experiment, the natural, unenriched, and unactivated quartz-glauconite rock from the “Adamivka II” deposit demonstrated significant sorption capacity for all nine pesticide formulations tested.
Second, the outcome depended on the specific substance and the quantity of rock applied.
Third, for certain formulations, the detectable concentration was reduced to zero under the experimental conditions—a result interpreted in the original study as 100% absorption.
Based on these findings, the authors concluded that glauconite rocks hold promise for the remediation of areas contaminated with pesticide residues.
What do the results not yet prove?
They do not demonstrate that 10–100 g of glauconite rock per liter of laboratory solution is equivalent to a specific, universal application rate per hectare in field soil.
They do not justify the claim that the same sorption percentage would be achieved in any actual soil.
Nor do they prove the complete chemical degradation of the sorbed molecules.
Finally, the results obtained cannot be automatically extrapolated to any finished complex product containing glauconite.
This does not diminish the value of the work; on the contrary, it defines the next logical stage of research.
How should this experiment be continued today?
A recent review by Masini and Abate effectively provides a methodological framework for such further work: to ensure a valid comparison of sorbents, it is necessary to clearly specify the temperature, contact time, solid-to-liquid phase ratio, initial concentration range, analytical method, and limits of detection and quantification, as well as to investigate kinetics, sorption isotherms, and desorption. To better approximate real-world conditions, the authors also recommend accounting for humic substances, colloidal particles, and the ionic strength of the solution. (MDPI)
To continue our work, I consider the following program to be optimal:
| № | Stage | What to research | What for? |
|---|---|---|---|
| 1 | Characterization of raw materials | XRD, XRF, particle size analysis, BET, CEC, Fe/K, mineral impurities | To accurately describe a specific glauconitic material |
| 2 | Pure active substances | Instead of just trade names — standards for specific pesticides | Ensure reproducibility |
| 3 | Kinetics | 5 min, 30 min, 1, 6, 24, 48 h | Determine the rate at which equilibrium is established. |
| 4 | Isotherms | Series of initial concentrations | Calculate Kd, Kf, and Freundlich/Langmuir parameters. |
| 5 | Effect of pH | Acidic, neutral, and alkaline environments | Determine the limits of effectiveness |
| 6 | Desorption | Sequential washing cycles | Check the bond strength |
| 7 | Comparison of materials | Natural rock, enriched glauconite, activated glauconite, quartz control | Determine the specific contribution of glauconite |
| 8 | Real soil | Sand, black soil, soil with varying humus content | Transition from a solution to a soil system. |
| 9 | Core-drilling test | Water filtration through soil | Assess pollutant migration |
| 10 | Biological stage | Microorganisms, plants, rhizosphere | Moving from sorption to ecosystem restoration |
It is precisely this type of experiment that would enable the transition from the result “the substance is sorbed” to a full-fledged technology:
localization → immobilization → desorption control → biodegradation → soil remediation.
Practical perspective
Our initial research focused primarily on the issue of sites used for the long-term storage of pesticides.
Today, this area of study can be viewed from a broader perspective.
Glauconite-bearing rock has the potential to serve as a component of mineral barriers, land reclamation mixtures, filtration layers, soil conditioners, or integrated remediation technologies.
However, it is crucial to fundamentally reframe the problem itself.
The goal is not simply to “cover the contamination with a sorbent.”
The objective is to reduce the mobility and bioavailability of the hazardous substance, prevent its migration into water, and subsequently ensure the controlled transformation of the pollutant and the restoration of the soil ecosystem’s normal functioning.
That is precisely why mineral sorption must be combined with chemical control, organic matter, microbiological processes, and vegetation.
A study of the quartz-glauconite rock from the “Adamivka II” deposit demonstrated the significant capacity of the natural, unbeneficiated material to reduce the concentration of nine tested pesticides in model aqueous solutions.
Under the specific experimental conditions, maximum uptake ranged from 50% for Baytan to 100% for DDT, Chlorophos, DDVP, and Cimbush. For most of the pesticides, a positive correlation was observed between the amount of glauconite rock used and the level of uptake.
These results align with the current international understanding of clay minerals as potential sorbents for organic pollutants. At the same time, contemporary research highlights the significant influence of factors such as the specific properties of the pesticide, mineral composition, pH, organic matter content, ionic environment, and competition from other compounds. (MDPI)
Therefore, the next step should not be a mere repetition of the previous experiment, but rather its further development using modern methodological approaches.
In such a system, glauconite should be viewed not merely as a natural sorbent, but as a functional component of technologies for remediating contaminated soil.
This leads directly to the next topic: how the properties of glauconite can be utilized in complex soil systems and GREENODIN products.
Scientific sources used and recommended
Author and compiler of the publication: Tymur LEVDA
Based on the research findings of Yu.B. Kozub and contemporary scientific sources, with his consent
