This study investigates the removal of tungsten from simulated water using biopolymer coated particles (i.e. chitosan coated clay) and natural clay. The effects of initial tungsten concentration (from 20 to 500 ppm) and water pH (4, 5.5 and 6.4) on zeta potential and tungsten removal were studied for both chitosan coated clay and natural clay. It was found that the net surface charge of natural...

this study aimed to develop techniques for purification of cyanotoxins dissolved in water -particularly those produced by microcystis aeruginosa species - using natural clay, chemically modifiednatural clay, commercial clay and ion exchange and adsorbent resins. except for natural clay, chemical pretreatment was required to increase the adsorption capacity of the treatment materials. all the cl...

The mechanical properties of non-vulcanized natural rubber and dialyzed natural rubber-clay nanocomposites have been studied by uniaxial deformations to evaluate the reinforcement efficiency of the clay. We show that while non-rubber molecules contribute to auto-reinforcement, removal of these molecules improves significantly the performance of clay as reinforcement agent. These mechanical prop...

The vertical migration of M. incognita juveniles introduced at 20 cm from the roots was studied in five natural soils, 100% silica sand, 95% silica sand with 5% clay, 90% silica sand with 10% clay, and 95% silica sand with 5% clay as a concentrated layer. In natural soils the percentage of juveniles capable of migrating 20 cm and penetrating the roots decreased when the percentage of clay and s...

Particles with nanometer dimensions (nanoparticles) are all around us. The finest particles of sand are blown by the wind over thousands of kilometers. The finest particles of soils are either eroded by the wind in extremely dry conditions or by water under wet conditions and deposited hundreds of kilometers or more from the origin. The air contains nanoparticles of carbon, ice, and oxides and ...

[1] The role of phyllosilicate fabrics in fault gouge is a poorly understood component of the mechanical and hydrologic behavior of brittle fault zones. We present 90 fabric intensity measurements using X-ray texture goniometry on 22 natural clay-rich fault gouges from low-angle detachment faults (Death Valley area detachments, California; Ruby Mountains, Nevada; West Salton Detachment Fault, C...

In this study, removal of copper (Cu(2+)) and zinc (Zn(2+)) from aqueous solutions is investigated using Cankiri bentonite, a natural clay. During the removal process, batch technique is used, and the effects of pH, clay amount, heavy metal concentration and agitation time on adsorption efficiency are studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms are applied in order to...

BACKGROUND Metalloporphyrin ions, with planar shape, have been known to intercalate horizontally and diagonally between montmorillonite layers. Perpendicular intercalation inside montmorillonite has not been reported earlier. This work aims at achieving perpendicular intercalation inside montmorillonite in natural clays. Possible intercalation inside other forms of natural clay will also be inv...

Inspired by the layered aragonite platelet/nanofibrillar chitin/protein ternary structure and integration of extraordinary strength and toughness of natural nacre, artificial nacre based on clay platelet/nanofibrillar cellulose/poly(vinyl alcohol) is constructed through an evaporation-induced self-assembly technique. The synergistic toughening effect from clay platelets and nanofibrillar cellul...

—Brightly colored frogs of Dendrobatidae contain alkaloid-based chemical defenses which appear to be utilized as a deterrent to predators. The conspicuous coloration of these frogs is generally considered to be an aposematic signal to color-visioned predators. A previous field-based experiment tested this hypothesis in the dendrobatid frog Oophaga pumilio (Strawberry Poison Frog) from the La Se...