Mathematical modeling of the sedimentation process for determining the fractional composition of suspensions

Exceptional prospects for use in science, technology and industry are opened by highly dispersed powders (ultradispersed diamonds, nanoceramics, medicinal powders) and materials based on them. The properties of such materials depend on the particle size determined by sedimentation analysis. An equation is proposed for processing sedimentation analysis data, which does not depend on the size distribution law of polydisperse system particles, and is used to describe the distribution functions of particles with radii for clay suspensions. A program in the Microsoft Visual Basic for Applications (VBA) language has been created for calculating the fractional composition of suspensions according to the proposed equation; the correctness of its operation on a model system has been checked and confirmed. Experimental research has confirmed that the use of the developed program and the "Search for a solution" add-on for the MS Excel environment makes it possible to determine the fractional composition of suspensions. It has been proven that the proposed method can be used to analyze polydisperse systems. It has been found that for the suspensions under consideration, as containing 25 fractions, it is possible to determine the integral curve of the distribution of the masses of the particles of the dispersed phase along the radii. This allows to assert the possibility of using the proposed equation for processing sedimentation analysis data, which does not depend on the law of mass distribution of polydisperse system particles by size. Thus, there is reason to assert about the possibility of a reasonable determination of the fractional composition of any polydisperse systems. It is possible to obtain certain effects from the introduction of sedimentation analysis data processing according to the proposed equation in production, where the fractional composition of dispersed phases is regulated.

INFLUENCE OF BENTONITE CLAYS ON THE MINERAL COMPOSITION OF RED TABLE WINES

Использование суспензий бентонитовых глин при обработке виноматериалов в процессе их осветления и стабилизации оказывает влияние на минеральный состав вин. Виноматериалы могут обогащаться катионами металлов, оказывающими разнонаправленное влияние на качество и розливостойкость вина. Исследованы изменения элементного состава виноматериалов в результате их обработки 32 образцами бентонитовых глин различных торговых марок. Объектами исследования были образцы виноматериалов из винограда сортов Каберне-Совиньон, Мерло и Молдова, собранного на территории Краснодарского края в 2019 г. Методами ИСП-АЭС и ИСП-МС определен элементный состав виноматериалов до обработки суспензиями бентонитовых глин и после нее. Установлено, что обработка бентонитовыми глинами привела к изменению концентраций практически всех определяемых элементов в образцах виноматериалов. Во всех образцах виноматериалов после обработки снизились концентрации B, Cu, Zn и увеличились концентрации Ag, Al, Cd, Ni, Na, Sb, Sn, Pb, Ti, Fe. As и Hg не были обнаружены ни в исходных, ни в обработанных образцах виноматериалов. Концентрации As, Cd, Hg, Pb, которые регламентируются в Российской Федерации, во всех обработанных образцах виноматериалов были существенно ниже установленного максимального уровня. Концентрации других элементов – Ag, B, Cu, Na, Zn, Ni, нормируемых в документах ЕС и МОВВ, в исследованных обработанных образцах виноматериалов оказались также значительно ниже нормативов. Таким образом, все исследованные бентонитовые глины могут быть рекомендованы к использованию при производстве вин. The use of suspensions of bentonite clays in the processing of wines in order to clarify and stabilize them has a significant effect on the mineral composition of wines. In this case, wines can be enriched with metals cations, which have a different effect on the quality and persistence of wine. Changes in the elemental composition of wine materials as a result of their treatment with 32 samples of bentonite clays of various brands were studied. The objects of the study were samples of wine materials from grapes of the varieties Cabernet Sauvignon, Merlot and Moldova, collected on the territory of the Krasnodar region in 2019. The methods of ICP-NPP and ICP-MS were used to determine the elemental composition of wine materials before and after treatment with bentonite clay suspensions. It was found that the treatment with bentonite clays led to a change in the concentrations of almost all detectable elements in the samples of wine materials. In all samples of wine materials after treatment, the concentrations of B, Cu, Zn decreased and the concentrations of Ag, Al, Cd, Ni, Na, Sb, Sn, Pb, Ti, Fe. As and Hg were not detected in either the initial or treated samples of wine materials. The concentrations of As, Cd, Hg, Pb, which are regulated in the Russian Federation, in all processed samples of wine materials were significantly lower than the established maximum level. The concentrations of other elements – Ag, B, Cu, Na, Zn, Ni, normalized in the EU and the International Organization of Vine and Wine documents, in the studied processed samples of wine materials were also significantly lower than the standards. Thus, all the studied bentonite clays can be recommended for use in the production of wines.

MIXING PROCESSES AND EQUIPMENT. CONSTRUCTION MIXTURES AND MIXTURES FOR MANUFACTURING CONSTRUCTION MATERIALS. LECTURE 9

The article presents materials of Lecture 9 Theory of carrying and lifting, construction and road vehicles and equipment, which describes mixing machines, concrete mixtures, their dosage, quality and homogeneity. The process of concrete mixing and energy aspects of its production are described. The data on mixers used for producing mortars and clay suspensions are presented. The design of a special mixer for producing polystyrene-silicate mineralized granules and the production technology for hollow silicate spheres based on the working process of a special mixer are described.

Analisis Campuran Tanah Liat dan Batu Kapur Bukit Pecatu Sebagai Instrumen Pemanen dan Penampung Air Hujan

This research originated from the large number of limestone mining in the Pecatu Hill area and it caused deep niches. On the other hand, the problem of water scarcity is the main thing, because the characteristics of karst rocks can escape, dissolve and absorb water. The condition of the ex-niche mining and water shortages are two different problems. But in this study, trying to combine these problems into a solution with the aim of making experiments that can make limestone from Pecatu Hill have the potential to hold water for a long time in the form of a miniature reservoir model. This miniature reservoir model is made with a mixture of clay suspensions of various concentrations (0%, 5%, 10% and 15%). This miniature reservoir model is tested for discharge and absorption of water which is assumed to be rainwater puddle to determine the ability to absorb rainwater. The result of this test is that the miniature reservoir with a mixture of 15% clay suspension has the ability to withstand a decrease in rainwater shrinkage of 0.04L / minute and has a small water absorption capacity of 10.91% compared to other concentrations. This shows that the miniature limestone reservoir of Pecatu Hill with a mixture of 15% clay suspension has potential as an instrument for harvesting and collecting rainwater. So this is expected to be utilized by the villagers of Pecatu Hill as an instrument for harvesting and collecting rainwater.

A New Look at the Purported Health Benefits of Commercial and Natural Clays

Clays attributed to have medicinal properties have been used since prehistoric times and are still used today as complementary medicines, which has given rise to unregulated “bioceutical” clays to treat skin conditions. Recently, clays with antibacterial characteristics have been proposed as alternatives to antibiotics, potentially overcoming modern day antibiotic resistance. Clays with suggested antibacterial properties were examined to establish their effects on common wound-infecting bacteria. Geochemical, microscopical, and toxicological characterization of clay particulates, their suspensions and filtered leachates was performed on THP-1 and HaCaT cell lines. Cytoskeletal toxicity, cell proliferation/viability (MTT assays), and migration (scratch wounds) were further evaluated. Clays were assayed for antibacterial efficacy using minimum inhibitory concentration assays. All clays possessed a mineral content with antibacterial potential; however, clay leachates contained insufficient ions to have any antibacterial effects. All clay leachates displayed toxicity towards THP-1 monocytes, while clay suspensions showed less toxicity, suggesting immunogenicity. Reduced clay cytotoxicity on HaCaTs was shown, as many leachates stimulated wound-healing responses. The “Green” clay exhibited antibacterial effects and only in suspension, which was lost upon neutralization. pH and its interaction with clay particle surface charge is more significant than previously understood to emphasize dangers of unregulated marketing and unsubstantiated bioceutical claims.

Reduction of Hg(II) by Fe(II)-Bearing Smectite Clay Minerals

Aluminosilicate clay minerals are often a major component of soils and sediments and many of these clays contain structural Fe (e.g., smectites and illites). Structural Fe(III) in smectite clays is redox active and can be reduced to Fe(II) by biotic and abiotic processes. Fe(II)-bearing minerals such as magnetite and green rust can reduce Hg(II) to Hg(0); however, the ability of other environmentally relevant Fe(II) phases, such as structural Fe(II) in smectite clays, to reduce Hg(II) is largely undetermined. We conducted experiments examining the potential for reduction of Hg(II) by smectite clay minerals containing 0–25 wt% Fe. Fe(III) in the clays (SYn-1 synthetic mica-montmorillonite, SWy-2 montmorillonite, NAu-1 and NAu-2 nontronite, and a nontronite from Cheney, Washington (CWN)) was reduced to Fe(II) using the citrate-bicarbonate-dithionite method. Experiments were initiated by adding 500 µM Hg(II) to reduced clay suspensions (4 g clay L−1) buffered at pH 7.2 in 20 mM 3-morpholinopropane-1-sulfonic acid (MOPS). The potential for Hg(II) reduction in the presence of chloride (0–10 mM) and at pH 5–9 was examined in the presence of reduced NAu-1. Analysis of the samples by Hg LIII-edge X-ray absorption fine structure (XAFS) spectroscopy indicated little to no reduction of Hg(II) by SYn-1 (0% Fe), while reduction of Hg(II) to Hg(0) was observed in the presence of reduced SWy-2, NAu-1, NAu-2, and CWN (2.8–24.8% Fe). Hg(II) was reduced to Hg(0) by NAu-1 at all pH and chloride concentrations examined. These results suggest that Fe(II)-bearing smectite clays may contribute to Hg(II) reduction in suboxic/anoxic soils and sediments.

Modelling and Experimental Investigation on the Settling Rate of Kaolinite Particles in Non-Ideal Sedimentation Stage under Constant Gravity

We compared the catalytic effects of two polymers (soluble starch and apple pectin) on the flocculation of kaolinite suspension. Moreover, the relationship between the zeta potential value and the time when kaolin particle sedimentation occurred was verified, and the mechanism of flocculation was analyzed. Additionally, a constitutive model was proposed to simulate the non-ideal sedimentation of clay particles in an aqueous system under constant gravity. This model not only considers the inhomogeneity of the solute but also simulates the change in clay concentration with time during the deposition process. This model proposes a decay constant (α) and sedimentation coefficient (s). The model can also be used to calculate the instantaneous sedimentation rate of the clay suspensions at any time and any depth for the settling cylinder. These sedimentary characteristics were simulated by adopting the established deposition model. The results show that the model is capable of predicting the time required for the complete sedimentation of particles in the aqueous system, suggesting the feasibility of engineering wastewater treatment, site dredging, etc.