Bentonite Suspensions Research Articles

The Effect of Particle Sizes on the Concentration Dependence of the Surface Tension of Aqueous Suspensions of Bentonite

The paper presents experimental results on the dependence of surface tension on the concentration of a suspension of bentonite (0 - 10% by weight). The isotherms σ of aqueous suspensions of bentonite are characterized by local minima in the concentration range of 3-4 mass% of the solid phase. It has been established that a decrease in the average particle size leads to the disappearance of the extremum on the surface tension isotherms. The data obtained led to the conclusion that the most important factors affecting the nature of the isotherms of the surface tension of bentonite suspensions are the degree of dispersion and the presence in the aqueous suspension of bentonite, both colloidal and coarse particles.

Implementation of an acoustic levitator experimental setup for the investigation into drying kinetics of single droplets

In recent years, acoustic levitation has increasingly been used to examine single droplets during the drying process. Steady levitation of individual droplets in an ultrasonic field enables the contactless observation during drying. An experimental setup for a levitator is designed and used to determine the drying and levitation behavior of two different material systems. To ensure hot gas flow patterns similar to a falling droplet the ultrasonic reflector has been modified as a multi-hole nozzle through which conditioned hot air is flowing toward the levitated droplet. The surface temperature of the individual droplets is constantly measured via an infrared camera while a CMOS camera is used to track the associated volume change during the drying process. The measured temperature data and volume change from contour data can be used to determine the individual drying rate periods, calculate the heat transfer coefficients and ultimately the drying kinetics with high accuracy over a wide range of parameters. First experimental results for a TiO2 suspension and a Bentonite suspension show good repeatability and prove the suitability of the presented method for determining the drying kinetics of single suspension droplets.

Study on the Rheological Behavior of a Model Clay Sediment

Clay sediments are the main component of seabed sediment. Interactions between the nano-sized, disk-shaped and charged clay particles are complicated, as they control the sediment’s rheology. In this study, we studied the rheological behavior of the clay sediment modeled by laponite and bentonite suspensions experimentally using a rotational rheometer. The yield stress decreased when water content increased. Meanwhile, the yield stress of the laponite suspension first increased and then decreased with increasing salinity. It is considered that the face-to-face repulsive electrostatic interaction between clay platelets dominated the yield behavior. A yield stress model was developed to describe the change of the yield stress with both the water content and the salinity. When the system started to flow, the viscosity decreased with increasing shear. A master curve of viscosity is was from the viscosity-stress curves at different water contents if the applied shear stress was normalized by the yield stress and the viscosity normalized by a characteristic viscosity. This study provides a preliminary understanding of the clay sediment rheology and its mechanism for the investigation on the flowing of the sediment systems with strong interparticle interaction.

Ionic strength and polyelectrolyte molecular weight effects on floc formation and growth in Taylor-Couette flows.

Polyelectrolyte-driven flocculation of suspended particulate in solution is an important process in a variety of industrial processes such as drinking water treatment and composite material synthesis. Flocculation depends on a wide variety of physicochemical and hydrodynamic properties, which affect floc size, growth rate, and floc morphology. Floc formation and growth behavior is explored here using two different molecular weights of a cationic polyacrylamide flocculant and anisotropic Na-bentonite clay particles under a variety of solution ionic strengths. A Taylor-Couette cell with radial injection capabilities was used to study the effects of solution ionic strength and polyelectrolyte molecular weight on floc size, growth rate, and floc morphology during the flocculation process with a constant global velocity gradient. The floc size generally decreased with increasing ionic strength whereas the floc growth rate initially increased then decreased. This likely occurred due to charge screening effects, where increased bentonite aggregate size and a less expanded polyelectrolyte conformation at higher ionic strengths results in a decreased ability for the polyelectrolyte to bridge multiple bentonite aggregates. The densification of bentonite aggregates at higher ionic strengths resulted in floc morphologies that were more resistant to shear-induced breakage. With the exceptions of optimal dose concentration and dispersion coefficients, there were no clear differences in the floc growth rate behaviors for the two molecular weights studied. This work contributes to an improved understanding of the physicochemical complexities of polyelectrolyte-driven flocculation that can inform dosing requirements for more efficient industrial operations.

Clinical and experimental substantiation of the use of bentonite suspension in the complex rehabilitation of patients with chronic viral hepatitis C with concomitant non-alcoholic fatty liver disease

Introduction. One of the most severe diffuse liver diseases is chronic viral hepatitis C (CHC) combined with non-alcoholic fatty liver disease (NAFLD). After completing the treatment of CHC with drugs of direct antiviral action, there remains a high risk of further progression of liver fibrosis associated with the presence of comorbid pathology - NAFLD in patients. The above circumstances initiated us to search for new non-drug technologies to treat this category of patients. Purpose of the work: to study the effectiveness of use bentonite suspension in rats with a model of NAFLD and to substantiate the practicality of using bentonite in the complex treatment of CHC patients with concomitant NAFLD. Methods: experimental, anamnestic and clinical, general clinical, biochemical, determination of the HOMA index, leptin and adiponectin levels, ultrasonographic studies of the digestive system, bacteriological examination of feces, statistical methods.Results: According to microscopic examination, bentonite application in animals with the NAFLC model leads to a decrease in liver steatosis, restoration of bile formation and bile secretion, and protein-synthesizing liver function. In the blood, there was a positive dynamics to the restoration of energy-dependent transmembrane ion transport according to the activity of Na+/K+ -ATPase and Mg2+/Ca2+ -ATPase (in the liver tissue) and the balance of the antioxidant system (to restrain malondialdehyde and catalase activity). We examined 40 patients with CHC with concomitant NAFLD, who completed the course of antiviral therapy (AVT) and were divided into two groups. 1 (control) group (20 people) received a basic treatment complex (diet therapy, which corresponded to the Mediterranean diet, a regimen of dosed physical exertion, patients of 2 groups (20 people, the main group) additionally received a preparation based on bentonite clay inside - 10 days (1 dose three times a day) Evaluation of the effectiveness of treatment was carried out one month after the start of treatment. Conclusion: The treatment carried out in both groups was accompanied by positive dynamics in most of the diseaseʹs symptoms. But a significant advantage was observed in the second group, where the normalization of cholestatic and dyslipidemic syndromes was established, that is, the effect on the pathogenetic links of the progression of NAFLD was proved. The results obtained confirm the practicality of using the drug with bentonite in the complex treatment of CHC patients with concomitant NAFLD. Keywords: chronic viral hepatitis C, non-alcoholic fatty liver disease, bentonite clay,

Force measurements on an inclined plate moving a sediment/sand bed

To provide data for the numerical modelling effort on the impact of seabed nodule harvesting on the marine environment and infrastructure, an experimental study of the interaction between a simple lab-scale nodule harvester and sediment/sand is carried out. The lab-scale harvester is simplified by a moving inclined plate and the seabed sediment is modelled by a tank containing water and bentonite suspension, or sand, as sediment substitute. The forces acting on the plate by the sediment are measured and the dispersion of sediment particles in the water tank is visualized. Experiment results show that, for a high enough mass fraction, the bentonite suspension displays a yield-stress behavior; and indeed, a gel-like structure suspension may result. Sand, being non-cohesive in nature, gives a much greater acting force on the plate than bentonite sediment. Gel-like structure clay suspension gives a much greater force than fluidified suspension. Once dispersed into water, sand particles quickly settle while clay particles take a longer time to settle and form an emulsion layer on top of the sediment. The experiment results serve both as a means to calibrate and validate the numerical modelling, as well as to gain physical insights into the seabed/structure interaction.

Choline chloride based natural deep eutectic solvent for destabilization and separation of stable colloidal dispersions

In solid-liquid separation processes, coagulation/flocculation is one of the most popular techniques in treating wastewater, as it is efficient, simple, and economical. Consequently, the formation of a new environment friendly destabilizing agent needed for the development of this processes. Hence, the aim of this paper is to introduce a new green and cheap choline chloride (ChCl) based natural deep eutectic solvent (NADES) as a coagulant for clay-based dispersions which are known to be a highly stable colloidal systems. For the NADES preparation, lactic acid (LA) and ChCl were used as the hydrogen bond donor and acceptor, respectively with a 1:1 ratio. Furthermore, the individual components of the NADES; ChCl and LA were also separately tested as coagulants as well as a binary mixture of both. Zeta potential, turbidity, floc size distribution, settling behavior, and viscosity measurements were conducted to study the potential of NADES in destabilizing and separating of high-stable bentonite dispersions and determine the strength of the resultant flocs. Initially, at pH 10, bentonite suspension had a high turbidity of 347 NTU and zeta potential of -45 mV. At optimum concentration the reduction in turbidity and zeta potential were as follows: 5.32 NTU with -30.6mV, and 4.3 NTU with -22mV was achieved using ChCl alone and mixture of ChCl and LA (ChCl-Cl), respectively. NADES showed the most efficient performance with almost 100% turbidity removal and a significant reduction in the zeta potential of −18 mV. For the three tested coagulants (ChCl, ChCl-LA, and NADES), produced flocs ranged in size from 5μm to 36μm depending on the coagulant type and dosage were achieved. NADES produced the largest flocs followed by ChCl-LA and ChCl. The obtained results were also confirmed through settling rate and sediment volume in addition to the viscosity measurements of the resultant flocs.

Mesoscopic rheological modeling of drilling fluids: Effects of the electrolyte

Drilling fluid is a complex fluid, including base fluid and other materials, carrying out the vital functions during drilling operation such as cutting transport and controlling formation pressure. In order to optimize performance of a drilling process, a reliable rheological model is required in the computation of fluid flow dynamics. Time-independent Generalized Newtonian formulation are the most common models for describing the rheological behavior of drilling fluids due to its simplicity and ease of use, in spite the fact that they are not able to predict the normal stresses and could not consider effects of active components on the rheological behavior of the drilling fluid and also could not describe the internal microstructures changes in the fluid during its flow. In this paper, a rather simple model in the mesoscopic level of study through the Generalized Bracket formalism have been developed to consider the influence of salts and electrolytes on the rheology of drilling fluid which has received less attention in the previous models. The advantage of this model is that it provides a description for the structural and orientation changes during transient and steady state fluid flows beside prediction of the transient and steady rheological behavior of salt containing suspensions of bentonite in polymeric solutions. Comparison of the model predictions with the published data from literature shows that the model predictions for the effects of the drilling fluid components including clay and salts are in well agreement with those of the rheological experimental data.

Influence of stagnation gradient for face support calculation in Slurry Shield Tunnelling

AbstractIn slurry shield tunnelling, a reliable face support is presumed if a sufficient support pressure is transferred and the slurry excess pressure provides efficient support pressure on the soil skeleton. The required support pressure is calculated in reference to the groundwater pressure and the earth pressure. In this paper, the sliding wedge mechanism is applied. To ensure face stability, the support pressure transfer needs to be provided within the theoretical sliding wedge at the tunnel face. Therefore, the penetration depth of the bentonite suspension as a support medium has to be kept within limits. Research shows that certain penetration is required.The stagnation gradient defines the relation of the support pressure and the penetration depth of the suspension. The gradient has a described minimum, but also an undefined but existing maximum. The German standard DIN 4126 describes two cases for the minimum at each trench depth: Either the pressure losses due to the pressure acting outside the sliding wedge are less than 5 % or the stagnation gradient is at least 200 kN/m3. If the supporting pressure gradient is below 200 kN/m3, DIN 4126 defines rough reduction factors. For a more precise observation of the stagnation gradient, this paper presents a detailed supplement to the DIN 4126 approach taking the tunnel diameter and the angle of the sliding wedge into account. The aim is to determine the minimum recommended stagnation gradient for which no increase of the slurry excess pressure is necessary due to too deep penetration.

Effects of calcium chloride and poly(N,N-dimethylaminoethyl methacrylate) on the filtration rate of a bentonite suspension and the examination of the filtration mechanism

A bentonite suspension (1 wt%) was filtered, employing a cationic polymer, poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA), and an electrolyte, calcium chloride (CaCl2), as flocculants at a pH and temperature of 6 and 50 °C, respectively. The effect of the flocculant concentrations on the filtration rate (FR) was investigated. Additionally, the filtration mechanism was examined by calculating the specific cake resistance (SCR), investigating the size of the aggregates, and by X-ray diffraction (XRD) analysis. FR increased and SCR decreased with increasing flocculant concentrations. Furthermore, FR, with PDMAEMA, significantly increased at a lower concentration than with CaCl2. The microscopic observation revealed that aggregates were formed when CaCl2 (≥ 300 ppm) or PDMAEMA (≥ 25 ppm) were utilized. Additionally, it was clarified that the aggregate size with PDMAEMA was much larger than that with CaCl2, and that FR increased as the aggregate size increased. FR was further improved when both 100 ppm PDMAEMA and 300 ppm CaCl2 were added to the suspension. In the XRD pattern, it was observed that the peak intensity, attributed to the (001) plane between the bentonite layers, increased with increasing CaCl2 concentration. From this result, it was assumed that large and hard aggregates were formed by aggregating CaCl2 between bentonite layers and crosslinking the layers with PDMAEMA. Therefore, SCR decreased and the filtration rate increased.

A Way of Measuring the Surface Tension of a Suspension of Bentonites

Results are presented from pendant and sessile drop measurements of the dependence of surface tension σ of aqueous suspensions of bentonites on the period of surface formation. It is established that the sedimentation of particles is the most important factor affecting the accuracy and reproducibility of measurements of σ in suspensions of bentonites. A procedure is proposed that neutralizes the effect this factor has on the value of σ. Ways of measuring σ in which sedimentation is directed differently relative to the surface are used. Sedimentation is thus directed to the surface in the pendant drop approach, and away from the surface in the sessile drop technique. Measuring σ in these ways and averaging the results considerably reduces the error caused by sedimentation. Analysis of the concentration dependence of σ on the suspensions of bentonite shows that the sedimentation factor is almost completely eliminated when using this procedure.

Thermodynamic Interpretation on the Rheology of Aqueous Bentonite Suspensions

Since their exceptional rheological behavior, bentonite suspensions are widely used in engineering, industrial, agricultural, and drilling applications. So, the aim of the present study is to investigate the rheological properties of three types aqueous suspensions prepared with calcium bentonite (CaB), sodium bentonite (NaB) obtained from that by Na2CO3 activation, and NaB with the excess soda. The CaB taken from Giresun/Turkey region contains calcium smectite (CaxS) as clay mineral and opal CT (SiO2.nH2O) as impurity which is paracrystalline silica. Soda content by the activation and bentonite content in the suspension were changed in the interval of 2.5-15.0% and 5-20% by mass, respectively. CaxS completely converted to sodium smectite (Na2xS) by the activation with the soda content of 2.5% and then Na2xS+Na2CO3 mixtures formed. Rheological properties of these aqueous suspensions were measured using a Fann Viscometer. These properties reached their maxima by the most thixotropic Na2xS suspensions and greatly increased with the increasing of smectite content. Rheological plots drawn of the shear rate vs. shear stress in the interval of 170-1020 s-1 showed that the suspensions flow as a Bingham Plastic. Change in rheological properties depending on the smectite type and content as well as excess soda content was explained thermodynamically based on the chemical potential gradient between interlayer and dispenser waters.

Rheological behavior of water-clay suspensions under large amplitude oscillatory shear

Mixtures of solid particles and Newtonian fluids such as water-clay suspensions are prepared for industrial usage and have many engineering applications. Different methods, setups, and protocols are available to characterize rheological behavior of these aqueous suspensions. In this study, large amplitude oscillatory shear (LAOS) protocols are considered as the main goal for the first time to examine non-linear rheological behavior of sepiolite suspensions. Four types of sepiolite clays and a commercial bentonite clay as reference were used to prepare fresh water-clay suspensions. Viscoelastic non-linearities of suspensions were studied as a function of strain and strain-rate using Lissajous–Bowditch curves and non-linear quantitative parameters. Discovery Hybrid Rheometer (DHR-II) was used in oscillation sweep tests for measuring non-linear properties. Impact of frequency on the evolution of LAOS properties was also investigated by constructing Pipkin diagrams. Bentonite suspension an had ability of keeping its elastic characteristics at higher strains compared to sepiolite clays indicating that bentonite clay yielded more flexible and structurally stable suspension. Sepiolite suspensions presented higher elastic stiffness (gel-strength) compared to bentonite suspension at all frequencies. Strong correlation in viscous non-linear parameters indicated viscous dominant behavior for all clay suspensions in the non-linear regions. It was also demonstrated that there is some tendency of shear-thickening behavior, particularly more notable for bentonite suspension under viscous deformation. It is postulated that the reason is hidden behind the structural differences of bentonite (platelets like) and sepiolite (fiber like) clays. Although both clays are members of smectite group, their structures and viscosity build mechanisms are quite different.

Formulation and evaluation of β-cyclodextrin polymer microspheres for improved HTHP filtration control in water-based drilling fluids

β-cyclodextrin polymer (β-CDP) microspheres were investigated as high temperature resistant filtration reducers for water-based drilling fluid in this study. The microspheres were synthesized by crosslinking reaction between β-CD and epichlorohydrin with inverse emulsion polymerization. The structural and morphological characteristics of the prepared microspheres were examined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), particle size distribution measurement, and thermogravimetry analysis (TGA). The filtration control properties of the microsphere were evaluated via American Petroleum Institute (API) filtration test and high temperature and high pressure (HTHP) filtration test. The results indicated that β-CDP microspheres could effectively reduce the filtration of bentonite suspension both before and after thermal aging at 200 °C without significant influence on drilling fluid's rheology. A substantially enhanced filtration control behavior was observed after thermal aging, which was contrary with conventional filtration reducers. The β-CDP microspheres could absorb a large number of water and became swellable and deformable, which enhanced the compressibility of filter cake. What is more, hydrothermal reaction occurred for part of β-CDP microspheres under high temperature environment, resulting in the formation of numerous carbon spheres ranging from hundreds of nanometers to several micrometers. The β-CDP microspheres, bentonite particles and small carbon spheres in combination contributed to form a dense and compact filter cake with low permeability. β-CDP microspheres were potential candidates as environmental friendly and high temperature filtration reducers in deep well drilling.

Structure-rheological properties relationships in model drilling fluids formulated in aqueous solutions of carrageenan with varying chemical structures

Water-based drilling fluids (WDF) formulated with hybrid carrageenans (HY) recently showed attractive rheological and filtration properties, but the role of HY chemical structure on such WDF characteristics could not be established. Here, model drilling fluids were prepared by suspending sodium activated bentonite in two HY aqueous solutions, in order to assess relationships between the polysaccharide chemistry and the rheological-structural properties of the fluids. The rheological analysis of HY solutions indicates that the more sulfated HY is in coil conformation, whereas the other forms helices. The less sulfated HY promotes the slow build-up of a more elastic bentonite gel showing a larger yield stress, due to a less flocculated structure. A similar microscopic structure is achieved with the more sulfated HY, but a weaker gel is formed. In this suspension, the strain hardening behavior indicates that elasticity is ruled by flocs internal structure. Wide angle X-ray diffraction suggests that the weaker bentonite floc elasticity is related with a smaller number of bentonite lamellae in the aggregating stacks within the flocs. Overall, the set of results suggests that the carrageenan chemistry modulates the gel viscoelasticity by tuning the bentonite suspension structure at different length scales, from inter bentonite stacks to inter flocs distances.

Method and Mechanism of Regulating Rheological Properties of Water-Based Drilling Fluid by High-Frequency and High-Voltage Alternating Current Electric Field

Summary The rheology of drilling fluid is commonly regulated by chemical methods. In this work, a physical method of a high-frequency and high-voltage alternating current (AC) electric field to regulate the rheological properties of water-based drilling fluid is established. The effects of the electric field on the continuous phase and dispersed phase, as well as two kinds of water-based drilling fluids, were investigated, and the response relationship among rheological properties modeled by Bingham and Herschel-Bulkley (H-B) models and electric-field parameters was explored. Results showed that water conductivity increased when voltage reached 4 kV, whereas it was restored to the original state after 3 hours in the absence of an electric field, showing a memory effect. The effect was also observed on bentonite suspension, whose plastic viscosity increased with the aid of an electric field and decreased over time. Voltage showed the greatest effect on bentonite-suspension viscosity, followed by frequency and pulse-width ratio. Under the condition of voltage of 5 kV, frequency of 5 kHz, and pulse-width ratio of 80%, there was a maximum increase of 50% in viscosity. The addition of salts caused bentonite-suspension flocculation, and electric field reduced the consistency coefficient and relieved flocculation state. When polymers were incorporated in bentonite suspension, the electric field could decrease the adsorption amount between clay particles and polymeric additives such as amphoteric and acrylamide-based polymers. For two typical drilling fluids, the voltage of an introduced electric field was the main controlling factor to change the rheological properties; their plastic viscosity and consistency coefficient both started to increase when voltage reached 4 kV.

Synthesis, characterization, and performance of carboxymethyl chitosan with different molecular weight as additive in water-based drilling fluid

With increasingly intensified energy demand and environmental pressure, it has been of great interest to develop high-performance and environmentally friendly drilling fluid additives, and natural-derived biopolymers are promising candidates. In this work, carboxymethyl chitosan (CM-CS) with different molecular weight, namely high- (CM-HMWCS), medium- (CM-MMWCS1, CM-MMWCS2) and low-molecular-weight (CM-LMWCS) CM-CS, were prepared and the structural factors including molecular weight (MW), degree of deacetylation (DD) and degree of substitution (DS) were determined. The impact of different CM-CS on rheological, filtration and inhibition properties of bentonite-based drilling fluid was evaluated, as well as the bentonite-polymer interactions. The experimental results showed that the lower the MW the higher the DS, while the DD seemed unaffected during reactions. All obtained CM-CS could effectively reduce the yield point of bentonite suspension before and after aging at 135 °C and 150 °C for 16 h, and the lower MW ones had better yield point-reducing effect and showed little influence on plastic viscosity. Besides, different CM-CS possessed the ability to control filtrate loss as well, which showed a high dependence on MW, the CM-HMWCS had the best filtration reduction performance. Meanwhile, all CM-CS had better inhibition properties to prevent clay swelling and shale disintegration than conventional inhibitors, in which the CM-MMWCS2 with medium MW and relatively higher DS exhibited the best inhibition. Therefore, the obtained different CM-CS was versatile and could perform thinning, filtration reduction and shale inhibition properties. These properties were dominated by their amphoteric molecular structures, and also related to the molecular weight.

Elucidation of the aggregation mechanism of bentonite with cationic guar gum as flocculant and application to filtration

Cationized guar gum (CGG) was synthesized by imparting a positive charge to the natural polymer guar gum (GG) and was used as a flocculant for bentonite suspensions. The effect of CGG on bentonite aggregation was evaluated by sedimentation tests. The mechanism of aggregation with CGG is discussed in terms of the aggregate size and the amount of CGG adsorbed in the aggregate. The amenability of bentonite suspensions to filtration using CGG was also investigated. At the optimum CGG concentration, the sedimentation rate increased, the amount of bentonite in the supernatant solution decreased, and the size of the aggregates was the largest under all conditions. The adsorption amount of CGG in the aggregates increased with increasing CGG concentration. The use of low CGG concentrations did not provide sufficient crosslinking between bentonite particles, and the use of high CGG concentrations suppressed bentonite aggregation by causing electrostatic repulsion, because a large amount of CGG covered the bentonite particles; hence there was an optimum CGG concentration for improved bentonite aggregation. When the bentonite suspension was filtered under these optimum conditions for aggregation, the filtration was the fastest, demonstrating that it is possible to apply the filtration method with the use of CGG.

Lung Toxicity Analysis of Nano-Sized Kaolin and Bentonite: Missing Indications for a Common Grouping.

Kaolin and bentonite (nanoclay NM-600) are nanostructured aluminosilicates that share a similar chemical composition, platelet-like morphology, and high binding capacity for biomolecules. To investigate if these material-based criteria allow for a common grouping, we prepared particle suspensions of kaolin and bentonite with a similar hydrodynamic diameter and administered them to NR8383 alveolar macrophages in vitro and also to a rat lung using quartz DQ12 as a reference material. Bentonite was far more bioactive in vitro, indicated by a lower threshold for the release of enzymes, tumor necrosis factor α, and H2O2. In addition, in the lung, the early effects of bentonite exceeded those of kaolin and even those of quartz, due to strongly increased numbers of inflammatory cells, and elevated concentrations of total protein and fibronectin within the bronchoalveolar lavage fluid. The pro-inflammatory effects of bentonite decreased over time, although assemblies of particle-laden alveolar macrophages (CD68 positive), numerous type-2 epithelial cells (immunopositive for pro-surfactant protein C), and hypertrophic lung epithelia persisted until day 21. At this point in time, kaolin-treated lungs were completely recovered, whereas quartz DQ12 had induced a progressive inflammation. We conclude that bentonite is far more bioactive than equally sized kaolin. This argues against a common grouping of aluminosilicates, previously suggested for different kaolin qualities.

Regulation of oxidative-restorative processes in secondary fermentation of wine materials in sparkling wine technology

The expediency of using preparations of dry inactivated (cell walls) yeast - glutaroma, salcline, bioproject, elivite and activite in the technology of sparkling wines produced by classical and reservoir methods has been studied. Decreased activity of redox potential is found when using said preparations irrespective of method of secondary fermentation. The greatest effect is noted in the combined use of cell wall preparations and bentonite suspension. The use of glutaroma and elivite, as well as mixtures thereof with bentonite, provided the highest amount of antioxidant activity of sparkling wine in both secondary fermentation methods. During the secondary fermentation of the control sample, an increase in glutathione content was observed in the first 2 weeks, after which its concentration remained virtually unchanged for 90 days of observation. The introduction into circulation of glutaroma, activite, bioproject, salcline, activated the fermentation process, and the concentration of reduced glutathione increased. A marked increase in glutathione concentration was found in the combined use of bentonite suspension with glutaroma, elivite and bioprotect. The increase in glutathione content was observed during the whole period of observation. On the basis of the obtained data, the mechanisms of oxidation-reduction process in production of sparkling wines by classical and reservoir methods are justified.