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...

A montmorillonite clay and a palagonitic soil sample were sieved to produce a series of size fractions in order to investigate the role that extremely fine particle sizes play on absorption strengths in martian analog materials. Significant decreases in band strength for both samples were observed as particle size decreased. The less than 5-μm fractions had 1.4-, 1.9-, and 2.2-μm bands that wer...

A High Cation Exchange Capacity (HCM) montmorillonite clay has been prepared by acetate treatment of Zenith clay. The HCM has been evaluated for metal-uptake from aqueous solutions. The present data show that the cation exchange sites can play a significant role in the adsorption of metals in smectite clays. A theoretical analysis scheme has been developed which shows that permanent-charge site...

A procedure to determine the exchanger-phase composition (and thus the Na/Ca selectivity) of calcareous and gypsiferous soils was developed and tested on three soils and three phyllosilicate minerals. The procedure corrects for anion exclusion and mineral weathering by measuring the Cl, SO,,, and HCO3 in the soil solution and in the extracting solution. Anion exclusion was found to be significa...

−Singleand bi-solute sorption and desorption of 2-chlorophenol (2-CP) and 2,4,5-trichlorophenol (2,4,5TCP) in montmorillonite modified with hexadecyltrimethyl-ammonium (HDTMA) were investigated by sequential sorption and desorption. Effect of pH on the sequential sorption and desorption was investigated. As expected by the magnitude of octanol : water partition coefficient (K ow ), both sorptio...

The competitive adsorption of the cationic pesticide chlordimeform and the heavy metal zinc on montmorillonite was studied. For different concentrations of Zn used, chlordimeform decreases (in relation to Zn-free treatments) when the pesticide is adsorbed simultaneously with the metal, but increases when Zn is adsorbed previously to chlordimeform. When comparing the Ko values chlordimeform is s...

BACKGROUND The dispersion-aggregation behaviors of suspended colloids in rivers and estuaries are affected by the compositions of suspended materials (i.e., clay minerals vs. organic macromolecules) and salinity. Laboratory experiments were conducted to investigate the dispersion and aggregation mechanisms of suspended particles under simulated river and estuarine conditions. The average hydrod...

BACKGROUND Curcumin and vanillin are the two useful compounds in food and medicine. Bismuth nitrate pentahydrate is an economical and ecofriendly reagent. METHOD Bismuth nitrate pentahydrate impregnated montmorillonite KSF clay and curcumin were subjected to microwave irradiation. RESULTS Microwave-induced bismuth nitrate-promoted synthesis of vanillin from curcumin has been accomplished in...

The intercalation of captopril (CP) into the interlayers of montmorillonite (MMT) affords an intestine-selective drug delivery system that has a captopril-loading capacity of up to ca. 14 %w/w and which exhibits near-zero-order release kinetics.

The major objective is to expand upon the scientific knowledge regarding the changes in montmorillonite internal pore structure (air/water voids in the entire soil volume) and redistribution of water after treatment with EcSS 3000 soil stabilizer. The actual profile of water released on heating rather than determining the weight losses was used. An advantage of this procedure is that the result...