Properties and applications of palygorskite-sepiolite clays

Clay Minerals ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 443-453 ◽  
Author(s):  
E. Galan
Keyword(s):  
Clay Minerals ◽  
Crystal Morphology ◽  
Industrial Applications ◽  
Chemical Parameters ◽  
Principal Characteristics ◽  
Surface Active Agents ◽  
Physico Chemical ◽  
Wide Range ◽  
Surface Active ◽  
Fabric Surface

AbstractThe palygorskite-sepiolite group of clay minerals has a wide range of industrial applications derived mainly from its sorptive, rheological and catalytic properties which are based on the fabric, surface area, porosity, crystal morphology, structure and composition of these minerals. For assessing potential industrial uses, the mineralogical and chemical composition of the clay and its basic physical and physico-chemical parameters must be determined. Then some particular properties of commercial interest can be modified and improved by appropriate thermal, mechanical and acid treatments, surface active agents, organo-mineral derivatives formation, etc. In this paper, a revision of the principal characteristics of commercial palygorskite-sepiolite clays is presented, and potential uses are suggested according to these data. New products and applications are being investigated and those concerning environmental protection in particular, are noted. Finally, possible health effects of these elongate clay minerals are discussed.

The separation of clay mineral fractions with linear heavy liquid density gradient columns

Clay Minerals ◽  
1969 ◽  
Vol 8 (1) ◽  
pp. 59-69 ◽  
Author(s):  
G. Halma
Keyword(s):  
Clay Minerals ◽  
Density Gradient ◽  
Gradient Centrifugation ◽  
Heavy Liquid ◽  
List Type ◽  
Liquid Density ◽  
X Ray Diffraction ◽  
Surface Active Agents ◽  
Density Gradient Centrifugation Method ◽  
Surface Active

Because of increased interest in mineralogical analysis of soils a rapid, generally applicable method to separate clay minerals is needed, and such a method is described here. The technique is a modification of the heavy liquid density gradient centrifugation method which is commonly applied in mineralogical practice. Modifications are:(1)The use of suitable surface active agents to overcome the flocculation problem.(2)The use of the ultra centrifuge at about 33,000 g to hasten sedimentation.(3)The use of a linear density gradient which supplies in addition a quick identification of the mineral composition.Preliminary experiments, evaluating different variables (e.g. cation form, ultrasonic treatment, influence of surfactant), reveal the scope and limitations of the procedure presented.Clay minerals of different density can be separated. However, if the clay minerals of a mixture have overlapping densities, or if they contain a series of mixed-layer minerals, only a broad fractionation is possible. This is shown by X-ray diffraction and electron microscope studies of isolated zones (or parts of them) which develop in the centrifuged density gradient columns containing various pre-treated natural clays or clay mixtures.

scholarly journals Comparison of some physico-chemical parameters of kiwiberry (Actinidia arguta) cultivars from a cold climate

2019 ◽  
Vol 31 (2) ◽  
pp. 375-383 ◽  
Author(s):  
Miroslav Horák ◽  
Petr Šnurkovič ◽  
Ivo Ondrášek ◽  
Josef Balík ◽  
Varit Srilaong
Keyword(s):  
Ascorbic Acid Content ◽  
Cold Climate ◽  
Chemical Parameters ◽  
Actinidia Arguta ◽  
Fruit Species ◽  
Physico Chemical ◽  
Predominant Type ◽  
Fruit Skin ◽  
Wide Range ◽  
High Level

AbstractThe Actinidia genus includes a number of commercial fruit species with a wide range of countries of origin. Some species such as A. arguta or A. kolomikta are characterized by a high level of resistance to frost. The aim of this study was to compare the fruit of selected cultivars of kiwiberry. In the kiwiberry fruit, sucrose was the predominant type of sugar. Citric acid was dominant in all samples; it was most represented in the pulp of kiwiberry seedlings and in the skin of kiwiberry ‘Issai’. Kiwiberry fruits feature a higher ascorbic acid content in the skin in comparison with the commercial A. chinensis cultivars. Antioxidant activity of kiwiberry fruit skin was up to 18 times higher than that of the pulp. In view of the kiwiberry fruit having no hair, it is possible to eat the whole fruit, including the skin containing substances beneficial to health.

scholarly journals Thermal evolution of Andean iron oxide–apatite (IOA) deposits as revealed by magnetite thermometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gisella Palma ◽  
Martin Reich ◽  
Fernando Barra ◽  
J. Tomás Ovalle ◽  
Irene del Real ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Thermal Evolution ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Wide Range ◽  
Geological Models ◽  
Chilean Altiplano ◽  
Geochemical Studies ◽  
Modern Technologies ◽  
Magnetite Formation

AbstractMagnetite is the main constituent of iron oxide–apatite (IOA) deposits, which are a globally important source of Fe and other elements such as P and REE, critical for modern technologies. Geochemical studies of magnetite from IOA deposits have provided key insights into the ore-forming processes and source of mineralizing fluids. However, to date, only qualitative estimations have been obtained for one of the key controlling physico-chemical parameters, i.e., the temperature of magnetite formation. Here we reconstruct the thermal evolution of Andean IOA deposits by using magnetite thermometry. Our study comprised a > 3000 point geochemical dataset of magnetite from several IOA deposits within the Early Cretaceous Chilean Iron Belt, as well as from the Pliocene El Laco IOA deposit in the Chilean Altiplano. Thermometry data reveal that the deposits formed under a wide range of temperatures, from purely magmatic (~ 1000 to 800 °C), to late magmatic or magmatic-hydrothermal (~ 800 to 600 °C), to purely hydrothermal (< 600 °C) conditions. Magnetite cooling trends are consistent with genetic models invoking a combined igneous and magmatic-hydrothermal origin that involve Fe-rich fluids sourced from intermediate silicate magmas. The data demonstrate the potential of magnetite thermometry to better constrain the thermal evolution of IOA systems worldwide, and help refine the geological models used to find new resources.

scholarly journals Production and Purification of Amylase from Bacillus subtilis Isolated from Soil

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
G. Kalyani ◽  
E. M. Rajesh
Keyword(s):  
Bacillus Subtilis ◽  
Product Development ◽  
Deae Cellulose ◽  
Industrial Applications ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Ammonium Sulphate Fractionation ◽  
Extracellular Amylase ◽  
Maximal Production ◽  
Cellulose Column

In spite of progress in biotechnology and enzymology, the enzymes have been industrialized in recent years for the mounting up the product development in various arena. The ultimate goal of this study comprises the production and purification the amylase enzyme from the bacterial strain. A powerful amylase producer, Bacillus subtilis ISOLATE-4 was isolated, screened and identified from the soil sample. In order to produce extracellular amylase, various physico-chemical parameters were optimized. During optimization, the maximal production of amylase by the isolate at 48 hrs of incubation in 100 rpm was found to be 6.93U/ml, 5.94U/ml, 6.0U/ml at 45ºC, pH 6 with 1% substrate concentration respectively. Ammonium sulphate fractionation was done for rapid precipitation of the amylase at a concentration of 60% and exposed to dialysis showed the 25% purification fold of an enzyme. The dialyzed product was further subjected to DEAE-Cellulose column chromatography resulted in an increase up to 75% purification fold than crude enzyme. The amylase enzyme might be suitable for the liquefaction of starch, detergent, textile and several additional industrial applications.

scholarly journals Dendrimers: properties and applications.

2001 ◽  
Vol 48 (1) ◽  
pp. 199-208 ◽  
Author(s):  
B Klajnert ◽  
M Bryszewska
Keyword(s):  
Chemical Properties ◽  
Polymeric Materials ◽  
Industrial Applications ◽  
New Class ◽  
Research Technology ◽  
Concise Review ◽  
Physico Chemical ◽  
Wide Range ◽  
Physical And Chemical ◽  
And Chemical Properties

Dendrimers are a new class of polymeric materials. They are highly branched, monodisperse macromolecules. The structure of these materials has a great impact on their physical and chemical properties. As a result of their unique behaviour dendrimers are suitable for a wide range of biomedical and industrial applications. The paper gives a concise review of dendrimers' physico-chemical properties and their possible use in various areas of research, technology and treatment.

scholarly journals Industrial Applications of Clay Materials from Ghana (A Review)

2018 ◽  
Vol 34 (4) ◽  
pp. 1719-1734 ◽  
Author(s):  
R.B. Asamoah ◽  
E. Nyankson ◽  
E. Annan ◽  
B. Agyei-Tuffour ◽  
J.K. Efavi ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Environmental Remediation ◽  
Industrial Applications ◽  
Mineral Deposits ◽  
Industrial Minerals ◽  
Local Clay ◽  
Geothermal Fields ◽  
Geological Conditions ◽  
Wide Range ◽  
Clay Materials

Clay minerals are phyllosilicate groups naturally found in soils in all parts of the world. They have proven to be among the most essential industrial minerals because of their unique physicochemical properties and versatile applications within a wide range of fields including ceramics, construction, and environmental remediation, biomedical as well as cosmetics. Clay minerals are also primary to the production of other materials such as composite for secondary applications. In Ghana, clay mineral deposits are commonly found in several areas including soil horizons as well as geothermal fields and volcanic deposits, and are formed under certain geological conditions. This review seeks to explore the geographical occurrence and discusses the current uses of various local clay materials in Ghana in order to highlight opportunities for the utilization of these materials for other applications.

scholarly journals Density and surface tension of aqueous solutions of adjuvants used for tank-mixes with pesticides

2012 ◽  
Vol 58 (No. 12) ◽  
pp. 568-572 ◽  
Author(s):  
J. Janků ◽  
L. Bartovská ◽  
J. Soukup ◽  
M. Jursík ◽  
K. Hamouzová
Keyword(s):  
Surface Tension ◽  
Aqueous Solutions ◽  
Chemical Properties ◽  
Calculated Density ◽  
Surface Active Agents ◽  
Physico Chemical ◽  
Pesticide Formulations ◽  
Density Values ◽  
Surface Active

Adjuvants are surface active agents that are added to pesticide formulations or tank-mix to facilitate the mixing, application, or efficacy of these products. Addition of adjuvants changes the physico-chemical properties of spray liquid. In this work, we have focused in particular on surface tension and density of aqueous solutions of different adjuvants registered for mixing with herbicides. Eleven different adjuvants were subject of this study under laboratory conditions. An equation which enables determination of density of aqueous solutions in concentration range of 0&ndash;15 g/kg was designed. Average difference between the experimental and calculated density values amounts to &plusmn; 0.006%. The concentration dependence of surface tension was utilized to determine the critical micelle concentration (cmc). Evidently, the cmc of most tested adjuvants was lower than the amount recommended by manufacturer, especially in case of adjuvants Dedal 90 EC and Mero 33528. For adjuvant Trend 90 EC the recommended rate is even lower than that obtained for the cmc. Maximum reduction of the surface tension of water was achieved with adjuvants Silwet L-77 and Break Superb. &nbsp; &nbsp;

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