Illite Clay Research Articles

Y-Type Zeolite Synthesized from an Illite Applied for Removal of Pb(II) and Cu(II) Ions from Aqueous Solution: Box-Behnken Design and Kinetics

A Y-type zeolite was prepared from illite clay, which was activated and synthesized by a solid-phase alkali fusion technique with reduced reaction conditions and crystal methods. The optimal synthesis conditions were investigated using the Box-Behnken design for a NaOH/illite (mass ratio) of 1:2, an activation temperature of 185 °C, and an activation time of 2.7 h. The synthesized Y-type zeolites were characterized by various analytical techniques such as FT-IR, XRD, and SEM, and the results obtained show that small amounts of quartz and P-type zeolites are present in the synthesized products. The mixture was classified as a zeolitic mineral admixture (ZMA). The adsorption performance of ZMA on Pb(II) and Cu(II) in solution was evaluated by batch adsorption experiments. The results showed that ZMA had good adsorption performance for Pb(II) and Cu(II), with maximum adsorption amounts of 372.16 and 53.46 mg/g, respectively. From the investigation, it was concluded that the adsorption process is chemisorption occurring in monomolecular layers and relying on electrostatic adsorption, ion exchange and complexation of hydroxyl groups on the ZMA surface for heavy metal cations. The ZMA reusability result shows that sodium chloride has the ability to regenerate the active site by restoring the ion exchange capacity without significant loss of Pb(II) and Cu(II) adsorption.

Production Technologies and Provenance of Ceramic Materials from the Earliest Foundry of Pre-Roman Padua, NE Italy

The earliest foundry site of Pre-Roman Padua, in the Veneto region (north-eastern Italy), provided evidence of craft activities and residential areas dated between the end of the 9th and 1st centuries BCE. Common and fine wares were found, most of them belonging to two main ceramic classes: (i) highly dark-colored bodies with silicate inclusions; (ii) carbonate-tempered pots. Macroscopic and petrographic (POM) descriptions and spectroscopy—mineralogical (XRPD) and geochemical (XRF)—analyses were carried out to define the provenance and technological choices (production recipes and firing conditions). The first ceramic class comprised diverse local/regional productions made with a common geo-resource, consisting in quartz-rich illitic clays, for which pit firing conditions generally under 850–900 °C were adopted. The purification of the starting base clays, the tempering of the clayey pastes with silica-rich grains and/or the polishing of surfaces were accomplished for fine wares. The carbonate-tempered pottery probably corresponded to an allochthonous ceramic class that might be used in the trade of specific contents. As such pots were made out of different illitic clays and under different redox conditions, they might correspond to diverse productions. The adoption of precise choices in very specific wares, not belonging to any of these two main ceramic classes, suggests the trade of fine wares in the Veneto during the First Iron Age.

The main factor influencing reservoir quality of K1yc tight sandstones within volcano-sedimentary succession in the Dehui fault-depression of Songliao Basin, NE China

The main factor influencing high-quality reservoirs of the Lower Cretaceous Yingcheng Formation (K1yc) sandstones in the Dehui Fault-Depression of the Songliao Basin, NE China within volcano-sedimentary succession is still obscure. In the study area, K1yc sandstone reservoirs has exhibited stronger heterogeneity and more complicated diagenetic alteration than terrigenous clastic sandstones. In this paper, K1yc sandstone reservoirs have been characterized through the aspects of petrology, physical property, and pore-types and -throat size. Accordingly, methods including core analysis, thin section, X-ray diffraction, scanning electron microscopy have been used in the study. Finally, the main factor controlling high-quality reservoirs within volcano-sedimentary successions has been concluded. The results reveal that the abundance of authigenic illite clays with forms of fibrous pore-bridging or lath-like pore filling primarily and rapidly reducing the reservoir performance. The chlorite coatings of framework grains should not effectively retard cementation process. Volcanic rock fragments are widespread within the volcano-sedimentary successions and tend to be dissolved by pore fluids, as then illitization should be the most important origin of authigenic illites. It has a critical significance for predicting high-quality reservoirs in the K1yc tight sandstones.

Performance of Composite Portland Cements with Calcined Illite Clay and Limestone Filler Produced by Industrial Intergrinding

The performance of five composite Portland cements (CPCs) with limestone filler (LF = 10%–25% by mass) and calcined illite clay (CIC = 10%–25% by mass) elaborated by intergrinding was analyzed in paste, mortar, and concrete. Hydration was studied by isothermal calorimetry, bound water, and XRD. Flow and compressive strength (2 to 90 days) were determined in standard mortar. Concretes (w/b = 0.45; binder content = 350 kg/m3; slump = 15 ± 3 cm) were elaborated to determine compressive and flexural strength, water penetration, and chloride migration. Intergrinding CPCs have a large specific surface area when LF + CIC increases, with a similar size range of clinker particles. Supplementary cementing material replacements decreased the heat rate, prolonged the dormant period, and decreased the acceleration rate at early ages. According to the Fratini test, all CPCs had positive pozzolanicity after 28 days, but XRD analysis showed Ca(OH)2 associated with monocarboaluminate phases. Mortar flow was slightly reduced when the proportion of CIC was increased. Mortar strength decreased when the sum of LF + CIC increased. CPC strength class was limited by compressive strength after 28 days. Concretes were workable, and the compressive strength after 28 days depended on the LF + CIC, and CIC contributed after 90 days. After 28 days, the water penetration depended mainly on the LF + CIC content. The chloride migration coefficient was also reduced when CPC contained more CIC and less LF.

Alkali-Activated Binary Binders with Carbonate-Rich Illitic Clay.

This work deals with the investigation of alkaline binders obtained from binary mixtures of carbonate-rich illitic clay from deposits in southern Italy and two industrial by-products with very different total composition and calcium content, i.e., blast furnace slag and type F fly ash, respectively. To improve the reactivity, the selected clay was ground in a ball miller and heated to 700 °C. The binary mixtures were alkali activated with NaOH solution at 4 M and 8 M, and the activated pastes were cured at room temperature and relative humidity >90% in a climatic chamber. Heat flow, total heat and compressive strength (2, 7 and 28 days) were determined. The hardened pastes were characterized by X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). Results show that the main reaction product in all samples is a gel or mixture of C-A-S-H/(N, C)-A-S-H type gel depending on the calcium content in the precursors. The paste, made up of a 1:1 weight proportion of carbonate-rich illitic clay and blast furnace slag, showed the formation of a more compact matrix than that observed in each individually activated component, achieving the considerable mechanical strength value of 45 MPa after 28 days, which suggests a very positive interaction between the two calcium-rich solid precursors. The binary mixture of carbonate-rich illitic clay and F fly ash showed relatively low compressive strength (below 15 MPa), which has been related to the poor reaction potential of fly ash regarding the alkali activation at room temperature. The modification of curing parameters is expected to improve the reaction of carbonate-rich illitic clay/fly ash blend. The clay activation method used in this study has been demonstrated to be suitable for larger scale industrial pre-treatment set-ups.

Removal of single dye and dye mixture from aqueous solution with alginate-coated calcined layered double hydroxide and illite clay composite beads

ABSTRACT Alginate-coated calcined layered double hydroxide and illite clay (Alg@CLDH@ Illite) composite beads were fabricated and tested for single and mixture dye adsorption from aqueous solution. Adsorption characteristics of the as-fabricated beads were assessed by using Methylene Blue (MB) and Congo Red (CR) as adsorbates. As-prepared samples were characterised by using X-ray diffraction (XRD), Thermogravimetry/Differential Scanning Calorimetry (TG–DSC), Fourier transform infrared spectroscopy (FTIR), and point of zero charge (pHpzc). The characterisations demonstrated that the incorporation of CLDH powder/clay mixture can not only enhance thermal stability but also can improve the adsorption performance. The adsorption kinetics of dyes onto composite beads followed the linear form of pseudo-second-order model and their equilibrium data were fitted well to the Freundlich model. The results showed that the Alg@CLDH@Illite composite is able to adsorb anionic and cationic dyes from a binary dye mixture with high sorption capacities in short time 50 min.

Fabric Formed Unstabilized Poured Earth: Four-Dimensional Wall Systems

This paper presents prototype design research into the drying, shrinkage, and cracking of unstabilized fabric-formed poured earth. An unstabilized poured earth mix became self-supporting in fabric formwork and hardened to the touch after 11 days. The same poured earth mix in conventional concrete planar impermeable formwork was wet and pliable after 22 days. Fabric formwork hung by expandable elastics also reduced cracking, allowing material shrinkage at form ties. Poured earth without Portland cement stabilization can create non-structural wall forms with less transportation of material to the site and less overall use of Portland cement. The mix tested here would match a site soil with a 29–30% illite or kaolinite clay content found by the authors in the southwestern United States.

Diverse sorption capacities and contribution of multiple sorptive sites on illitic clays to assess the immobilization of dissolved cesium in subsurface environments

The multiple sorptive sites on illitic clays (e.g., frayed edge [FES], type II [TS], and planar sites [PS]) are related to variable 137 Cs immobilization in subsurface environments. This study investigated the diverse Cs + sorption using 10 illitic clays under various competing K + (distilled water−10 −1 mol/L) and Cs + concentrations (10 −7 −10 −3 mol/L). In addition, the multisite cation exchange model was simulated the best-fit sorption models compared to experimental datasets, and subsequently, optimized the sorption capacities of multiple sorptive sites on the illitic clays. The best-fit sorption model exhibited that diverse Cs + sorption of 10 illitic clays was closely linked to the individual sorption capacities at the FES (1.76 × 10 −5 to 1.12 × 10 −4 eq/kg), TS (1.59 × 10 −3 to 9.76 × 10 −3 eq/kg), and PS (2.14 × 10 −2 to 1.51 × 10 −1 eq/kg). The FES predominantly sorbed Cs + at low aqueous-phase concentrations, whereas the TS and PS contributed to Cs + sorption at relatively high concentrations. These sorption capabilities were correlated to illite contents and crystallinity of 10 illitic clays so that such parameters could be significant factors to predict the Cs + sorption for illitic clays. Finally, the 1-D transport simulations showed significantly diverse Cs + retardation ( R d ≈ 20 to 100) at low dissolved Cs + , implying that the various FES capacities of illitic clays could play an important role on Cs + distribution in actual radioactive contamination sites. • 10 illitic clays had diverse Cs + sorption capacities at multiple sorptive sites. • Multisite cation exchange model was optimized to evaluate Cs + sorption to illitic clays. • Statistical relationship between Cs + sorption and mineralogical data was evaluated. • Selectivity coefficients of Cs + were affected by competing cation concentrations.

Lightweight aggregate: a sustainable alternative for reuse of sawdust waste in the industrial process

Sawdust generated by wood processing, both in industries processing and in tree felling, is a waste that has several applications for reuse, but, in many cases, it is still discarded irregularly in the environment, contaminating the soil, air, and water. The production of lightweight aggregate (LWA) can be an option for the reuse of this sawdust. The LWA is a gravel solution used in civil construction with the objective of reducing the weight of the structure, improving thermal and acoustic compliance, or as an option for locations where gravel is not available. In Brazil, and in most parts of the world, there are common clays available that can be used in the LWA production. The aim of this research was to produce an LWA for different applications, among them, as aggregate for civil construction, bricks, and as an adornment element. Formulations were tested to produce LWA containing illitic clay and sawdust. In the same way, for comparison, a commercial LWA was purchased, and formulations were made with clay and coal, and clay and fuel oil. The specimens were produced by pressing at 30 MPa in a cylindrical shape with a diameter of 19 mm and a height of 15 mm. After firing, the specimens were characterized by technological tests of water absorption, bulk density, compressive strength, X-ray diffraction analysis, and chemistry by X-ray fluorescence. The results indicated that the incorporation of sawdust in the formulations can be an alternative to produce LWA, once it obtained high strength and low density, compared to commercial LWA and to that produced with unattractive materials. Furthermore, it may contribute to the reduction of environmental impact, resulting from the disposal of sawdust and the generation of natural resources, necessary to produce construction materials.

Removal of Congo red from aqueous solutions by adsorption onto illite clay

Removal of Congo red from aqueous solutions by adsorption onto illite clay

Effects of Illitic Clay on the Phases, Microstructure, Physical Properties and Pyroplastic Deformation of Industrial Slag Ceramics.

Preparing ceramic materials is a meaningful way to treat and utilize industrial slags. In this work, high-performance and low-deformation industrial slag ceramics were prepared from Ti-extraction blast furnace slag and illitic clay. The phase composition and contents, microstructure, physical properties, and pyroplastic deformation of ceramic samples were investigated. With the increasing proportion of illitic clay, the main crystalline phase of ceramic samples changed from akermanite to Fe-bearing diopside. Moreover, the minor crystalline phases changed from perovskite and spinel to anorthite and titanite. The proportion of illitic clay was linearly related to the amorphous phase content. The dense microstructure comprised concentrated short-columnar and granular grains with a few isolated pores, whereas plate-like grains destroyed their denseness. An appropriate proportion of illitic clay helped to improve the physical properties, increase the high-temperature viscosity and reduce the deformation of the ceramics. The optimal proportion of illitic clay was 30%, and the prepared ceramic sample had a dense microstructure and excellent physical properties. Its bulk density was 2.82 g/cm3, bending strength was 62.17 MPa, and water absorption was 0.21%.

Raw kaolinitic–illitic clays as high-mechanical-performance hydraulically pressed refractories

The usage possibility of 19 composites of raw refractory clays from Serbia containing approximately 53.29% of SiO2 and 26.73% of Al2O3 is presented. The sum of fluxing oxides was 57.74%, while these materials contained 32% of quartz, 29% of kaolinite and 26% of illite–mica. Dilatometry tests revealed a sudden shrinkage with the peak at approximately 1115 °C, owing to the formation of mullite. The refractoriness was in the range of 1581–1718 °C, which classifies the composites from low- to high-duty refractories. Based on correlation analysis, the refractoriness mostly depended on the content of alumina. The lightness of the fired test pieces was lower after firing when compared to the dry samples, and it decreased with the firing temperature from reddish to grayish. The study presents a novel attempt to define all the necessary properties of raw refractory clays and products fired at the 1100–1300 °C range on a laboratory level. Most of these clays can be used as natural refractory materials for ceramic and glass furnace lining. The organic matter in some of the samples influences negatively the fast-firing process.Graphical Abstract

The effect of mineral composition on soil organic matter turnover in temperate forest soils

PurposeThe aim of this work was to determine the characteristics of SOM decomposition under forest vegetation and to investigate the influence of soil mineralogy on SOM turnover.MethodsThirteen Hungarian forest topsoil samples amended with maize residues were incubated at 20 °C for 163 days. The CO2 evolved was measured and the fast and slow decomposition rate constants (k1 and k2, respectively) of SOM were quantified using a first-order two pools model. Linear regression analysis was applied between the quantity of total mineralized carbon (TMC), k1 and k2 values and the mineralogical parameters of the soils.ResultsThe illite (R2 = 0.797, p < 0.001) and non-swelling clay mineral (R2 = 0.767, p < 0.001) content and the dithionite–citrate–bicarbonate-extractable Al (AlDCB, R2 = 0.708, p < 0.001) and ammonium-oxalate-extractable Al concentration (AlOX, R2 = 0.627, p < 0.01) reduced the TMC to the greatest extent. The AlDCB (R2 = 0.681, p < 0.001), AlOX (R2 = 0.583, p < 0.01) and illite (R2 = 0.545, p < 0.01) contents had strong negative relationship with the k1 value. The k2 value was only affected by the non-swelling clay mineral (R2 = 0.467, p < 0.05) and illite (R2 = 0.574, p < 0.01) contents.ConclusionThese results confirm that the mineral composition of the soil, including the Al oxide, non-swelling clay mineral and illite contents, may significantly inhibit the decomposition of SOM, showing that illite minerals may provide binding surfaces for SOM over a longer timescale.

Coaggregation of micro polystyrene particles and suspended minerals under concentrated salt solution: A perspective of terrestrial-to-ocean transfer of microplastics

This study evaluates the colloidal stability of polystyrene microplastics (PSMPs) in the presence of various mineral colloids. Although PSMPs were highly dispersive, they were found to be involved in the aggregation of each mineral colloid. The efficiency of mineral colloids to stimulate the coaggregation of PSMPs follows the order bentonite > kaolinitic soil clay > illitic soil clay > kaolinite > goethite > haematite. Surface charge density is likely a crucial factor that determines the efficiency of mineral colloids. In concentrated salt solution, PSMPs together with mineral colloids can be involved in various continuous and simultaneous electrochemical processes such as charge neutralization, double electric layer compression, van der Waals attraction stimulation and heteroaggregation. These processes may also occur in the estuary environments, where suspended mineral colloids may play an ultimate role in reducing the transport of microplastics into oceans while also intensifying microplastic enrichment in coastal sediments.

Electric properties of anorthite ceramics prepared from illitic clay and oil shale ash

Electrical properties during firing of anorthite ceramic prepared from mixtures of illitic clay (from Northeastern Hungary) and fly ashes (obtained from circulating fluidized bed combustion – IA4 and pulverized firing – ID4) with high content of CaO were investigated. Mixtures were prepared with 60 wt% of illitic clay and 40 wt% of oil shale ash. The ashes were hydrated prior to mixing, to prevent the reaction of free lime with water during sample preparation. The mixtures were subjected to thermal and structural analyses to describe the processes induced by thermal treatment. The contraction of the IA4 and ID4 samples reached 1.8% and 2.5%, respectively, at 1100 °C, which is significantly lower than that of the illitic clay (7%). X-ray diffraction (XRD) analysis revealed a presence of diopside, gehlenite, cristobalite, and leucite minerals as additional mineral phases in the prepared anorthite ceramics. Measurement of AC conductivity showed that after the decomposition of the CaCO3 at ∼880 °C, Ca2+ ions became the dominant charge carriers, and the electrical current was carried by a hopping mechanism throughout the studied temperature region. The electrical conductivity and the relative dielectric constant of the ID4 sample was higher compared to that of the IA4 sample. The relative dielectric constant reached values of 6 (sample IA4) and 8 (sample ID4) at 140 °C (after drying).

Hydrothermal injection breccia with organic carbon and nitrogen in the fossil hydrothermal system of Harghita Bãi, East Carpathians, Romania: an example of magmatic and non-magmatic element mobility in the upper continental crust

AbstractOrganic carbon and nitrogen fixed in illite (I) clays were identified in a hydrothermal breccia structure from the Harghita Bãi area of the Neogene volcanism of the East Carpathians. The potassium-illite (K-I) alteration related to an early magmatic-hydrothermal event (9.5 ± 0.5 Ma) was later replaced by ammonium-illite (NH4-I) (6.2 ± 0.6 Ma) owing to circulation of an organic-rich fluid. Several textural evolutions of breccia structures were recognized, such as ‘shingle’, ‘jigsaw’, ‘crackle’ and hydraulic in situ fractures. The high-field-strength element behaviours of the K-I and NH4-I argillic altered andesite are close to chondritic ratios, indicating no contribution of hydrothermal fluid, especially on NH4-I andesite alteration and the CHArge-and-RAdius-Controlled (CHARAC) behaviour within silicate melts. The rare earth element normalized patterns show two distinct trends, one with a Eu* anomaly (K-I) and the other with a Nd* anomaly (NH4-I), indicating a boundary exchange with the organic-rich fluid. The strongly depleted δ13C (V-PDB) measured for the NH4-I clays reflects values (−24.39 to −26.67 ‰) close to CH4 thermogenic oxidation, whereas the δ15N (‰) from 4.8 to 14.8 (± 0.6) confirmed that the N2 originated from post-mature sedimentary organic matter. The last volcanism (6.3 to 3.9 ± 0.6 Ma) and simultaneous volcano-induced tectonics in the proximity of the eastern Transylvanian basin basement increased the heat flow, generating lateral salt extrusion, diapirism and increased pressure in the gas reservoir. New pathways were opened that provided new circulation routes for basinal fluids to new and old permeable zones and expelled seeps from the biogenic petroleum system.

Results of cone and piston pull-out tests for evaluation of clay-soil adhesion

Adhesion between metal surfaces and soil can have significant effects on soil-tool interaction. The cone pull-out test (CPT) and piston pull-out test (PPT) for adhesion assessment were used in this study on smectite, illite and kaolinite clays at different water contents. In the CPT, the tangential adhesion stress (TAS) and cone adhesion (CA) were measured. In the PPT, the normal adhesion stress (NAS) and piston adhesion (PA) were measured. The results showed that the NAS and TAS depended on the type of clay. The ratios of NAS to TAS for smectite and kaolinite had the largest and smallest values, respectively. For all three types, NAS and TAS decreased as the water content (W) decreased. An increase in the thickness of the water film at the soil-metal contact surface reduced the stress required to separate the metal from the soil. The relationship between CA-W and PA-W for the three clay types differed. For smectite, a change in water content had no effect on CA or PA. For illite, an increase in water content decreased the CA and PA. For kaolinite, a bell-shaped curve formed such that, as water content increased, where W<liquid limit (LL), CA and PA increased and, where W>LL, CA and PA decreased. For all three clay soil types, NAS and PA were higher than TAS and CA at a specific water content. This demonstrated the effect of the metal-to-soil contact geometry on the adhesion parameters. The NAS and TAS values were classified in terms of clogging potential. Clogging potential is the adhesion of soil to the cutting tools or conveying system. The selection of the use of the CPT or PPT for adhesion assessment depended on the phenomenon being studied.

Illitization in the Mt. Simon Sandstone, Illinois Basin, USA: Implications for carbon dioxide storage

Clay mineral cementation is one of the most important controls on sandstone reservoir properties. In this paper, the diagenetic history of the Mt. Simon reservoir complex is studied to reveal the origin, timing, and controls of illitization. Samples of sandstone and shale from Mt. Simon reservoir complex were acquired from the Illinois Basin–Decatur Project (IBDP), a CO2 storage demonstration project in the central Illinois Basin. Petrographic, SEM, TEM, XRD analyses and K/Ar age dating were completed to identify the major detrital and diagenetic components of the samples and reveal illite to be the major clay component in all samples. Illitic clay coatings in the lower Mt. Simon reservoir are identified as a major control on reservoir properties by inhibiting major precipitation of authigenic quartz during illitization, resulting in highly permeable sandstone, essential for CO2 storage. The coating box-work morphology and mineralogy are indicative of a detrital smectite origin with subsequent illite growth associated with feldspar dissolution and kaolinite alteration. The mineralogy of bulk material and separate grain size fractions (2–0.6 μm; 0.6–0.2 μm; < 0.2 μm) with illite polytypes 2M1, 1M, and 1Md were quantified and age dated via 40K-40Ar methods. The shales or reservoir seals contain the highest proportions of detrital illite with illite in the lower Mt. Simon Sandstone reservoir identified as solely diagenetic. Two major events of illitization are identified throughout the Mt. Simon with more porous reservoir rock exhibiting the older event from approximately 360 to 315 Ma and tighter sandstone units with reservoir properties too low to be considered reservoir exhibiting illite dates from 250 to 220 Ma. This partitioning of illitization is attributed to varied mineralogy controlled by depositional changes and evolution of the greater basin.

Mechanical compaction mechanisms in the input sediments of the Sumatra subduction complex – insights from microstructural analysis of cores from IODP Expedition 362

Abstract. The input sediments of the North Sumatra subduction zone margin, drilled during IODP Expedition 362, exhibit remarkable uniformity in composition and grain size over the entire thickness of the rapidly deposited Nicobar Fan succession (seafloor to 1500 m b.s.f.), providing a unique opportunity to study the micromechanisms of compaction. Samples were prepared from dried core samples (from Sites U1480 and U1481) by both Ar-ion cross-section polishing and broad ion beam cutting and imaged with a field-emission scanning electron microscope (SEM). The shallowest samples (seafloor to 28 m b.s.f.) display a sharp reduction in porosity from 80 % to 52 % due to collapse of large clay-domain surrounding matrix pores associated with rotation and realignment of clay platelets parallel to the bedding plane. The deeper succession (28 to 1500 m b.s.f.) exhibits less rapid reduction in porosity from 52 % to 30 % by the progressive collapse of silt-adjacent larger pores through bending as well as subsequent sliding and/or fracturing of clay particles. In addition, there is a correlated loss of porosity in the pores too small to be resolved by SEM. Clastic particles show no evidence of deformation or fracturing with increasing compaction. In the phyllosilicates, there is no evidence for pressure solution or recrystallization: thus, compaction proceeds by micromechanical processes. An increase in effective stress up to 18 MPa (∼ 1500 m b.s.f.) causes the development of a weakly aligned phyllosilicate fabric mainly defined by illite clay particles and mica grains, while the roundness of inter-particle pores decreases as the pores become more elongated. We propose that bending of the phyllosilicates by inter-particle slip may be the rate-controlling mechanism. Pore size distributions show that all pores within the compactional force chain deform, irrespective of size, with increasing compactional strain. This arises because the force chain driving pore collapse is localized primarily within the volumetrically dominant and weaker clay-rich domains; pores associated with packing around isolated silt particles enter into the force chain asynchronously and do not contribute preferentially to pore loss over the depth range studied.

Changes in Chernozem Erosion Resistance Due to the Evolution of Clay Plasma in Western Ukrainian Region

The major problem of efficient agriculture in Ukraine is increasing rates of the water erosion in Chernozems. The aim of this research study is to describe the negative trends in the clay profile for evolution of various Chernozem sub-types, which lead to the reduction of erosion resistance. Cohesion strength between soil aggregates is determined dominating smectite minerals in clay plasma. Disturbing the stable balance between the organic and mineral matter are the main causes of soil disaggregation. Evolutionary changes of Chernozems clay plasma are studied using the methods of chemical and x-ray diffractometry analysis. The processes of de-humification have been destabilized the mineral colloidal complex and smectite-illit dynamic equilibrium in soils. From Haplic Chernozems to Greyzemic Chernozems, the substantial loss of highly dispersive smectite material is observed. The dominance of inactive illite clay in the arable layer of all Chernozems reduce the role of clay plasma in formatting of water-stable micro- and macrostructure. According to the anti-erosion properties of clay plasma, the Chernozems under study is found in the following order: Haplic Chernozem &gt; Greyzemic Chernozem. These properties reduce themselves following the increase in soil hydromorphism stimulating argillification in the middle and lower horizons due to the processes of lessivage and inter-soil weathering. Anthropogenic evolution of Chernozems, when caused by the changes in the silicate fraction of soils, is basically of irreversible degrading nature.