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....

Intercalation products based on ionic exchange reaction between cationic dye methylene blue and Na-montmorillonite were prepared. Montmorillonite particles intercalated with methylene blue were characterized using X-ray diffraction, infrared spectroscopy, elemental and thermo-gravimetric analysis. The results showed that intercalation of dye molecules within the interlayer spaces of montmorillo...

Diclofenac sodium (DS) is considered as priority anti-inflammatory pollutant because of its presence in water. In this paper, we addressed the issue of using organo-K10 montmorillonite as adsorbent of DS to reduce its negative effects on the environment. An organo-K10 montmorillonite (MK10-C16) was prepared by intercalating the organic cation cetyltrimethylammonium bromide (C16) in a K10 montmo...

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 ...

Oligonucleotides synthesized on a montmorillonite catalyst were analyzed directly. By mixing the catalyst with a matrix (2,4,6-trihydroxyacetophenone or 6-aza-2-thiothymine) and dibasic ammonium citrate, higher molecular weight products were detected compared with "classical" methods such as gel electrophoresis and HPLC with UV as a detector. The oligomers (30-mers and higher) were detected by ...

The biodegradation of 14C-labeled phenanthrene in the presence of particles of montmorillonite and fulvic and humic acid–montmorillonite complexes was studied in a batch system. A mathematical model that takes into account the contribution to mineralization by the slowly desorbing compound was used to calculate the initial mineralization rates. Sorption of phenanthrene to the particles was dete...

In this paper we report on ZnS nanoparticles produced by precipitation of zinc acetate and sodium sulphide and stabilized by cetyltrimethylammonium bromide (CTAB) in aqueous media and deposited on montmorillonite (MMT). For the deposition a new method based on intensive cavitation was used. The montmorillonite carrier was first disintegrated by intense turbulent mixing in an ultrasonic field in...

Surfaces of Wyoming SWy-2-Na-montmorillonite were modified using ultrasonic and hydrothermal methods through the intercalation and adsorption of the cationic surfactant octadecyltrimethylammonium bromide (ODTMA). Changes in the surfaces and structure were characterized using X-ray diffraction (XRD), thermal analysis (TG), and electron microscopy. The ultrasonic preparation method results in a h...

Montmorillonite, a bioinert clay mineral, was examined as a novel vector for an oral gene-delivery system. The complex of montmorillonite and plasmid DNA encoding the enhanced green fluorescent protein (EGFP) gene was prepared at various weight ratios, and then transfected into cultured intestinal epithelial cells (IEC-6) in vitro. The EGFP gene was clearly transcribed when the transfection was...

Bentonites are widely used for waste repository systems because of their hydrodynamic, surface and chemical-retention properties. MX 80 bentonite (bentonite of Wyoming) contains approximately 85% Na/Ca-montmorillonite and 15% accessory minerals. The dominant presence of Na/Ca-montmorillonite in this clay mineral could cause it to perform exceptionally well as an engineered barrier for a radioac...