The negative electrical field around clay particles whose edge thickness is small relative to the Debye length of the diffuse double layer associated with the planar surfaces may spill over into the edge region. Such a spillover may affect B adsorption by the clay. This study was conducted to determine the effect of edge surface properties of 2:1 clay on B adsorption. Pyrophyllite, which shows ...

novel collagen-based hydrogel nanocomposites were synthesized by graft copolymerization of acrylamide and maleic anhydrid in the presence of different amounts of montmorillonite, using methylenebisacrylamide (mba)and ammonium persulfate (aps) as crosslinker and initiator, respectively. the optimum amount of clay on the swelling properties of the samples was studied. it was found that the hydrog...

A method for preparing and observing clay platelets for size and shape analysis using scanning electron microscopy (SEM) was developed. Samples of the clay platelets were prepared by polyelectrolyte-assisted adsorption onto a pyrolytic graphite surface. The use of graphite as a substrate was advantageous because of the low number of secondary electrons emitted from it during imaging by SEM. The...

Scaling relationships are identified between NMR longitudinal relaxation times and clay dispersion quality in polymer-paramagnetic clay nanocomposites. Derived from a previously published analytical relationship developed from a lamella-based model, the scaling relationships are based on the enhancement of NMR relaxation rates with increasing exfoliation and dispersion homogeneity. The paramagn...

The homoionic calcium-montmorillonite was used to synthesize a red iron oxide/clay pigment in a CO2-rich brine solution (0.5 M of NaCl) by using an agitated batch-reactor (engineer autoclave). The operating conditions were 15 days of reaction, 200 bars of pressure and 150 degrees C of temperature. SEM/EDS, STEM/EDS, XRD and Infrared Spectrometry were performed to characterize before and after r...

The immobilization of Candida antarctica lipase B (CALB) was performed by physical adsorption on both neat and organo-modified forms of sepiolite and montmorillonite. The influence of different parameters, e.g., solvent, enzyme loading, cross-linking, and type of clay support, on immobilization efficiency and catalyst hydrolytic activity has been investigated. The highest hydrolytic activities ...

The grafting reaction between a trifunctional silylating agent and two kinds of 2:1 type layered silicates was studied using FTIR, XRD, TGA, and 29Si CP/MAS NMR. XRD patterns clearly indicate the introduction of 3-aminopropyltriethoxysilane (gamma-APS) into the clay interlayer. In the natural montmorillonite, gamma-APS adopts a parallel-bilayer arrangement, while it adopts a parallel-monolayer ...

The antibacterial activity of silver and cationic surfactant modified smectites from North Patagonian, Argentina, were tested in growth inhibition of Escherichia coli bacteria by the test of susceptibility on solid medium. The exchange reactions were carried out using Ag and hexadecyltrimethylammonium (HDTMA) cations in larger amounts than those conventionally required to form monolayer on the ...

In this study, we investigate the interaction of Rhodopseudomonas Palustris (R. Palustris) with montmorillonite clay. The adsorption of bacteria on the clay surface was also determined as a function of the initial bacterial quantity, pH, temperature and ionic strength. At different initial bacterial quantities, the percentage of bacteria adsorbed ranged from 61.07% to 77.57%, and the higher per...

An aluminous montmorillonite has been synthesized at hydrothermal conditions (623 K, 120 MPa) and compared to the natural Na-exchanged Wyoming montmorillonite (Na-SWy2). The synthetic product is characterized by a high cation exchange capacity (83 meq/100g) and ethylene glycol specific surface area (764 m 2 /g) similar to Na-SWy2 but with a higher purity with one crystalline phase. Compacted sm...