kaolinite and magnesium-trisilicate

The development of novel materials and approaches for effective energy consumption and the employment of renewable energy sources is one of the current trends in modern material science. With this respect, the number of researches is focused on the effective harvesting and storage of solar energy for various applications. Phase change materials (PCMs) are known to be able to store thermal energy of the sunlight due to adsorption and release of latent heat through reversible phase transitions. Therefore, PCMs are promising as functional additives to construction materials and paints for advanced thermoregulation in building and industry. However, bare PCMs have limited practical applications. Organic PCMs like paraffins suffer from material leakage when undergoing in a liquid state while inorganic ones like salt hydrates lack long-term stability after multiple phase transitions. To avoid this, the loading of PCMs in porous matrices are intensively studied along with the thermal properties of the resulted composites. The loading of PCMs in microcontainers of natural porous or layered clay materials appears as a simple and cost-effective method of encapsulation significantly improving the shape and cyclic stability of PCMs. Additionally, the inclusion of functional clay containers into construction materials allows for improving their mechanical and flame-retardant properties. This article summarizes the recent progress in the preparation of composites based on PCM-loaded clay microcontainers along with their future perspectives as functional additives in thermo-regulating materials.

Topics: Algorithms; Clay; Diatomaceous Earth; Geothermal Energy; Hot Temperature; Kaolin; Magnesium Silicates; Models, Molecular; Models, Theoretical; Phase Transition; Porosity; Thermal Conductivity; Thermodynamics

An in vitro study indicated that certain antacids and adsorbents may decrease the oral availability of th two widely used antimalarial agents chloroquine and pyrimethamine. To determine if this data was applicable to the clinical (in vivo) situation, plasma levels of one of the antimalarial agents (chloroquine) were followed in six Negro--Arab volunteers both when given alone and when taken with separate doses of two of the implicated interactants (magnesium trisilicate and kaolin). This in vivo work confirmed the in vitro findings; chloroquine area under the plasma concentration-time curve data were decreased by both magnesium trisilicate (18.2%) and kaolin (28.6%). Similar results could be expected for pyrimethamine. It is suggested therefore, to avoid loss of drug, that the antimalarials should not be taken with gastrointestinal medications of this type or that their administration should be separated by at least 4 h to reduce the risk of them interacting in the gut, thus preventing drug adsorption to the antacids/adsorbents, and loss of systemic availability.

Topics: Adult; Biological Availability; Chloroquine; Humans; Intestinal Absorption; Kaolin; Magnesium; Magnesium Silicates; Male; Silicic Acid; Silicon Dioxide

In this study, Gradient Boosted Regression Trees is applied, for the first time, to predict governing factors for methylene blue (MB) adsorption on a variety of adsorbents involving clay minerals, such as kaolinite and sepiolite together with industrial wastes red mud and fly ash, and alkali activated materials synthesized from aforementioned raw materials. Dataset was constructed using electronic databases, such as ScienceDirect, Scopus, Elsevier, and Google, experimental studies published between 2005 and 2022 were covered. The final dataset included experimental conditions, such as adsorbent type, adsorbent properties (surface characteristics, density, and chemical modifications), pH of the medium, adsorbent dosage, and temperature; and it involved 914 datapoints, which were extracted out of 75 papers (out of ∼1360 initially screened). Among distinct parameters, initial adsorbate concentration was found to be the most dominant factor affecting the MB uptake. Concordantly, pH of the solution medium, raw material selection, and modification types were also found to be significant in MB adsorption. Results showed that in terms of raw material and modification types, sepiolite and chemical (acid and/or alkaline modification) and thermal treatments, respectively, come forward as the most powerful candidates for enhanced MB adsorption performance. Modifications applied on adsorbents should be evaluated separately, as there is no general rule applicable for all experimental conditions, and the strength of the contribution of modification type also depends on initial adsorbate concentration. Implementation of various imputation methods showed the importance of reporting experimental factors, such as surface area, in the literature. Range of applicability of the suggested modeling procedure was assessed to help experimenters in testing MB uptake under novel experimental conditions.

Topics: Adsorption; Alkalies; Clay; Coal Ash; Hydrogen-Ion Concentration; Industrial Waste; Kaolin; Kinetics; Magnesium Silicates; Methylene Blue; Water Pollutants, Chemical

Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemistry data permits the estimatation of indigo loading in archeological Maya Blue, which is in the range of 0.2 to 1.5 wt %. These results support a view of 'genuine' Maya Blue-type materials as complex polyfunctional organic-inorganic hybrids.

Topics: Bentonite; Chromatography, High Pressure Liquid; Chromatography, Liquid; Electrochemistry; Humans; Indigo Carmine; Isatin; Kaolin; Magnesium Compounds; Magnesium Silicates; Mass Spectrometry; Oxidation-Reduction; Silicon Compounds

The performance of two bacteria, Arthrobacter viscosus and Streptococcus equisimilis, and the effect of the interaction of these bacteria with four different clays on the retention of diethylketone were investigated in batch experiments. The uptake, the removal percentages and the kinetics of the processes were determined. S. equisimilis, by itself, had the best performance in terms of removal percentage, for all the initial diethylketone concentrations tested: 200, 350 and 700 mg/L. The uptake values are similar for both bacteria. A possible mechanism to explain the removal of diethylketone includes its degradation by bacteria, followed by the adsorption of the intermediates/sub-products by the functional groups present on the cells' surfaces. The assays performed with bacteria and clays indicated that the uptake values are similar despite of the clay used, for the same microorganism and mass of clay, but in general, higher values are reached when S. equisimilis is used, compared to A. viscosus. Kinetic data were described by pseudo-first- and pseudo-second-order models.

Topics: Absorption; Aluminum Silicates; Arthrobacter; Bentonite; Biodegradation, Environmental; Clay; Environmental Restoration and Remediation; Kaolin; Magnesium Silicates; Pentanones; Streptococcus; Wastewater; Water Pollutants, Chemical

Adsorption of three surfactants of different nature, Triton X-100 (TX100) (non-ionic), sodium dodecylsulphate (SDS) (anionic) and octadecyltrimethylammonium bromide (ODTMA) (cationic) by four layered (montmorillonite, illite, muscovite and kaolinite) and two non-layered (sepiolite and palygorskite) clay minerals was studied. The objective was to improve the understanding of surfactant behaviour in soils for the possible use of these compounds in remediation technologies of contaminated soils by toxic organic compounds. Adsorption isotherms were obtained using surfactant concentrations higher and lower than the critical micelle concentration (cmc). These isotherms showed different adsorption stages of the surfactants by the clay minerals, and were classified in different subgroups of the L-, S- or H-types. An increase in the adsorption of SDS and ODTMA by all clay minerals is observed up to the cmc of the surfactant in the equilibrium solution is reached. However, there was further TX100 adsorption when the equilibrium concentration was well above the cmc. Adsorption constants from Langmuir and Freundlich equations (TX100 and ODTMA) or Freundlich equation (SDS) were used to compare adsorption of different surfactants by clay minerals studied. These constants indicated the surfactant adsorption by clay minerals followed this order ODTMA>TX100>>SDS. The adsorption of TX100 and ODTMA was higher by montmorillonite and illite, and the adsorption of SDS was found to be higher by kaolinite and sepiolite. Results obtained show the influence of clay mineral structure and surfactant nature on the adsorption capacity of surfactants by clays, and they indicate the interest to consider the soil mineralogical composition when one surfactant have to be selected in order to establish more efficient strategies for the remediation of soils and water contaminated by toxic organic pollutants.

Topics: Adsorption; Alkanes; Aluminum Silicates; Bentonite; Clay; Kaolin; Magnesium Compounds; Magnesium Silicates; Minerals; Octoxynol; Quaternary Ammonium Compounds; Silicon Compounds; Sodium Dodecyl Sulfate; Soil Pollutants; Spectrum Analysis; Surface-Active Agents

Algal removal abilities of 26 clays/minerals were classified into three categories according to the 8-h equilibrium removal efficiency (Q8h) and removal rate at a clay loading of 0.7 g/L. Type I clays (sepiolite, talc, ferric oxide, and kaolinite) had a Q8h > 90%, a t50 (time needed to remove 50% of the algae) < 15 min, and a t80 < 2.5 h. Type II clays (6 clays) had a Q8h 50-90%, a t50 < 2.5 h, and a t80 > 2.5 h. Type III clays (14 clays) with Q8h < 50%, t50 > 8 h and t80 > 14 h had no practical value in removal of algal blooms. When the clay loading was reduced to 0.2 g/L, Q8h for all the 25 materials decreased to below 60%, except for sepiolite whose Q8h remained about 97%. The high efficiency for sepiolite to flocculate M. aeruginosa cells in freshwaters was due to the mechanism of netting and bridging effect.

Topics: Aluminum Silicates; Antacids; China; Clay; Eutrophication; Ferric Compounds; Flocculation; Fresh Water; Kaolin; Kinetics; Magnesium Silicates; Microcystis; Minerals; Soil; Talc

In vitro experiments were performed to investigated the extend of adsorption of ciprofloxacin to kaolin, magnesium trislilicate and to a starch obtained from the tubers of Tacca involucrata (Tacca starch) and to explore the effect of varying pH on this adsorption. Activated charcoal, a standard adsorbent and antidote in the management of poisoning due to a variety of chemical agents was employed as a comparing standard. The results of the study indicate that kaolin and magnesium trisilicate adsorbed ciprofloxacin effectively while the adsorption of the drug on the starch was relatively low. Adsorption was dependent upon the quantity of the adsorbed used. Kaolin or magnesium trisilicate could serve as an effective antidotal alternative to activated charcoal in the management of ciprofloxacin poisoning. Except in cases of poisoning due to ciprofloxacin, the concurrent administration of the drug with kaolin or magnesium trisilicate may be contraindicated. Tacca starch, however, may not really be recommended for the management of ciprofloxacin poisoning.

Topics: Adsorption; Antacids; Anti-Infective Agents; Charcoal; Ciprofloxacin; Kaolin; Magnesium Silicates; Starch

We studied one sample of commercial sepiolite and two samples of commercial vermiculite--clay minerals proposed as replacements for asbestos--and tested in vitro their abilities to activate complement, to lyse erythrocytes, and to elicit the production of reactive oxygen species (ROS) with human polymorphonuclear leukocytes (PMN) or bovine alveolar macrophages (AM); their behavior was compared with that of asbestos fibers obtained from the Union International Contra Cancer (UICC) as reference standards, as well as with kaolinite and illite, main members of the clay mineral family. Since in short-term in vitro tests the biological activity of mineral particles seems especially related to the active sites on their surface, we first measured the specific surface area of each mineral. Sepiolite was unreactive in two of the three tests we used (complement activation and ROS production) and able to lyse a minimal percentage of red blood cells. Vermiculite was shown to be incapable of activating complement, to have a moderate hemolytic activity and a high ability to elicite ROS production, although lower than that of chrysotile. Sepiolite, therefore, might be of more interest than vermiculite, given the low level of biological effects detected during the tests used to compare both clay minerals with asbestos fibres. The ROS production does not seem to require phagocytosis. A high ROS production was observed with kaolinite: this result casts doubt on the ability of pathogenic mineral dusts in vitro to induce a greater release of ROS than nonpathogenic mineral dusts.

Topics: Acridines; Aluminum Silicates; Animals; Antacids; Antidiarrheals; Asbestos; Asbestos, Crocidolite; Asbestos, Serpentine; Carcinogens; Cattle; Clay; Complement Activation; Dose-Response Relationship, Drug; Erythrocytes; Hemolysis; Humans; Kaolin; Linear Models; Luminescent Measurements; Luminol; Macrophages, Alveolar; Magnesium Silicates; Minerals; Neutrophils; Reactive Oxygen Species; Tetradecanoylphorbol Acetate; Zymosan

Topics: Acebutolol; Adsorption; Antihypertensive Agents; Charcoal; Kaolin; Magnesium; Magnesium Compounds; Magnesium Silicates; Metoprolol; Nadolol; Oxprenolol; Silicic Acid; Silicon; Silicon Compounds; Timolol

Topics: Absorption; Antihypertensive Agents; Charcoal; Kaolin; Magnesium; Magnesium Compounds; Magnesium Silicates; Propranolol; Silicic Acid; Silicon; Silicon Compounds; Thermodynamics

Variability in the bioavailability of orally administered trimethoprim due to Magnesium trisilicate and Kaolin-pectin has been investigated. The concentration of trimethoprim in blood was determined spectrofluorometrically at 0, 15 and 30 minutes and 1, 2, 4 and 6 hours. The area under the blood concentration curve of trimothoprim was significantly decreased, when the drug was given concurrently with magnesium trisilicate or kaolin-pectin. The mean decrease in maximum blood concentration of trimethoprim in magnesium trisilicate and kaolin-pectin treated groups was 49.94% and 29.42% respectively. The data suggest that a clinically significant interaction may occur due to concurrent administration of trimethoprim with these drugs.

Topics: Animals; Antacids; Biological Availability; Drug Interactions; Female; Kaolin; Magnesium; Magnesium Silicates; Male; Pectins; Rats; Silicic Acid; Silicon Dioxide; Trimethoprim

A study was made of the effect of 6 commonly used gastrointestinal preparations on the absorption of propranolol using an in vitro experimental model. The constituents examined were activated dimethicone, aluminium hydroxide gel, bismuth carbonate, kaolin, magnesium carbonate, and magnesium trisilicate. A slight decreased propranolol absorption was given by kaolin (-13.0%), the other components showed smaller effects ranging from -6.8% to +6.6%. None of the results were statistically significantly different from control absorption values.

Topics: Aluminum Hydroxide; Animals; Antacids; Bismuth; Carbonates; In Vitro Techniques; Intestinal Absorption; Kaolin; Magnesium; Magnesium Silicates; Propranolol; Rats; Silicic Acid; Silicones; Simethicone