Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that mor...

Hydrous amorphous Al (HAO), Fe (HFO), and Mn (HMO) oxides are ubiquitous in the subsurface as both discrete particles and coatings and exhibit a high affinity for heavy metal contaminants. To assess risks associated with heavy metals, such as Pb, to the surrounding environment and manage remedial activities requires accurate mechanistic models with well-defined transport parameters that represe...

The self-assembly of low molecular weight gelators confined within the nano-scale interlayer space of organo-montmorillonite is likely to be different from that under normal conditions (bulk space). Four kinds of gelators, 1-methyl-2,4-bis(N'-n-octadecylureido) benzene (MBB18), 1-methyl-2,4-bis(N'-n-dodecylureido)benzene (MBB12), bis(4'-stearamido phenyl) methane (BSM18) and bis(4'-octanamido p...

Surface modification of clay minerals has become increasingly important for optimizing the practical application of bentonites, kaolins, and clays. We describe the reaction of montmorillonite, an important mineral in bentonites, with cationic poly(ethylene oxides). Poly(ethylene oxides), PEOs, with molecular masses between 1550 and 35000, were modified by substituting the OH end groups by bromi...

Adsorption of quinoline (pKa 5 4.92) and background electrolyte (CaCl2) onto specimen kaolinite and montmorillonite were measured as a function of pH (3–7.5) and ionic strength (1–10 mM), and as a function of quinoline concentration (0.2–1.55 mM) at fixed pH values of maximum adsorption. Maximum sorption of quinoline occurred at pH 3.5–4.0 for kaolinite, and pH 3.0–5.0 for montmorillonite. At t...

A key parameter for the application of polymer gels in water shut off treatment is the adsorption of polymer gel onto the rock surface. So, the adsorption properties of a nanocomposite hydrogel were discussed in this research by crosslinking of sulfonated polyacrylamide/sodium montmorillonite aqueous solutions with chromium triacetate. The X-ray diffraction patterns indicated that exfoliated ty...

background:  ramsar, a northern city in iran, lies on the coast of the caspian sea. this city has areas with some of the highest levels of natural radiation measured to date. the radon concentration in some areas of ramsar is up to 3700 bq m–3. on the other hand, due to high level of humidity, damp-proof barriers should be used in construction of new buildings in radon prone areas of this city....

Batch and flow methods are usually not suitable for measuring kinetics of ion-exchange reactions on soils and soil constituents. These reactions are usually very fast. Thus, a rapid kinetic method must be employed. A pressure-jump relaxation technique was used in this study to investigate the kinetics of Ca-Na and Ca-K exchange on montmorillonite. Single relaxations were observed in both system...