Removal of atrazine, lindane and diazinone from water by organo-zeolites.

Systematic adsorption tests were carried out to determine the efficiency of organo-zeolite (OZ) for removal of atrazine, lindane and diazinone from water. The hydrophobic character of OZ-pesticide interactions was confirmed by measuring the amount of pesticides sorbed on zeolite samples modified with 25, 50, 75 and 150 mmol of stearyldimethylbenzylammoniumchloride (SDBAC)/kg of zeolite. The effects of adsorbent particle size, solid content in the suspension and the initial pesticide concentration in the solutions were also investigated.

Adsorption of mycotoxins by organozeolites.

Adsorption of zearalenone (ZEN), ochratoxin A (OCHRA) and aflatoxin B1 (AFB1) on natural zeolite, clinoptilolite, modified with different amounts of octadecyldimethylbenzyl ammonium (ODMBA) ions was investigated. Results showed that adsorption of hydrophobic ionizable ZEN on unmodified zeolite tuff was very low and that adsorption on organozeolites increased with increasing hydrophobicity of the zeolitic surface. The adsorption was independent of the form of ZEN in solution and the solution pH, indicating that hydrophobic interactions with ODMBA are responsible for ZEN adsorption.

Surface modification of sepiolite with quaternary amines.

This study was aimed at elucidating the mechanism of adsorption of quaternary amines, stearyldimethylbenzylammoniumchloride (SDBAC), as monomers and as micelles, distearyldimethylammoniumchloride (DDAC) and hexadecyltrimethylammoniumchloride (HTAC), on the surface of sepiolite. The adsorption capacity for these surfactants onto sepiolite, calculated by fitting the experimental data to the Langmuir-Freundlich equation, were 324% (SDBAC), 278% (DDAC), and 258% (HTAC) of the cation exchange capacity of sepiolite. The Mg(2+) ions released during the exchange process were higher than the CEC value of sepiolite because of the simultaneous dissolution of the present minerals.