Simultaneous adsorption of aflatoxin B and zearalenone by mono- and di-alkyl cationic surfactants modified montmorillonites.

Organo-montmorillonites (OMts) modified with mono- and di-alkyl cationic surfactants were prepared to remove polar mycotoxin aflatoxin B (AFB) and weak polar, hydrophobic mycotoxin zearalenone (ZER) simultaneously. The structural and surface properties of the prepared OMts were investigated. In vitro adsorption experiments were carried out to simulate the in vivo conditions of gastrointestinal tract of animals by a batch mode. The adsorption of AFB and ZER in both single and binary-contaminate systems were investigated systematically. Both OMts showed super enhanced adsorption capacities towards AFB and ZER whenever in single and binary-contaminate systems compared with raw Mt, indicating the effectiveness of the prepared OMts acted as mycotoxins adsorbents. DODAC-Mt showed a higher adsorption capacity towards AFB and ZER than OTAB-Mt. The equilibrium data of AFB on OMts were fitted satisfactorily with Freundlich and Linear models, suggesting the co-existence of different adsorption mechanism which were proposed to be ion-dipole interactions (between surfactant cations and carbonyl groups of AFB) and adsorption/partition mechanisms. The adsorption isotherms of OMts to ZER matched best with Linear models, implying the adsorption/partition mechanism. For simultaneous adsorption, the adsorption process of one mycotoxin was slightly affected by the presence of the other mycotoxin due to the requirement of partial same sorption sites. In addition, the solution pH had negligible influence on the adsorption process of OMts, meaning no desorption occurred when the adsorbents pass through from stomach to intestine as animal feed.