Surfactant modified zeolites - new efficient adsorbents for mycotoxins

The in vitro mycotoxins adsorption by natural clinoptilolite-heulandite rich tuff modified with different amounts of octadecyldimethyl benzyl ammonium chloride (Do) and dioctadecyldimethyl ammonium chloride (Pr) was investigated. Two methods of preparation of the organo-zeolites (OZs) were used-wet process (activation in suspension) and dry process (tribochemical process). The chemical stability of the two organically modified zeolites (OZs) obtained by wet and dry processes was investigated after an electrolyte treatment at pH 1, 7 and 10 by thermal (DTA/DDTA/TG) analysis and IR spectroscopy. Results of IR and thermal analysis, after electrolyte treatment, confirm that OZs obtained by wet and dry processes are completely stable in the investigated pH region. Mycotoxin binding studies showed that all the OZs effectively adsorbed aflatoxin B1, zearalenone, ochratoxin A and the ergopeptine alkaloids. The method of preparation of the OZs had no influence on adsorption of mycotoxins. The non-linear shape of the mycotoxin adsorption isotherms of OZs suggests that modification of zeolitic tuff with long chain organic cation Pr, by both wet and dry processes of preparation, formed the same specific active sites which are relevant for adsorption of aflatoxin B1, zearalenone and ochratoxin A by OZs. (C) 2003 Elsevier Inc. All rights reserved.