Adsorption behaviors of aflatoxin B1 and zearalenone by organo-rectorite modified with quaternary ammonium salts

Organo-rectorites (ORts) modified with different quaternary ammonium salts were prepared to remove polar mycotoxin aflatoxin B1 (AFB1) and weak polar, hydrophobic mycotoxin zearalenone (ZER). The structural and surface properties of the prepared ORts were studied. The intercalation of organic cationic surfactants expanded the interlayer of rectorite and increased the hydrophobicity. In vitro adsorption experiments were carried out to simulate the in vivo conditions of gastrointestinal tract of animals by a batch mode. The prepared ORts showed super enhanced adsorption capacities towards AFB1 and ZER compared with raw rectorite, indicating the effectiveness of the prepared ORts as mycotoxins adsorbents. The ORts modified with longer chain surfactant molecules possessed a higher adsorption capacity towards mycotoxins. In addition, with increasing the modifier dosage, the adsorption capacity increased first and then decreased. The best adsorption capacity was achieved when the dosage of the modifier increased to 2.0CEC. The adsorption of both AFB1 and ZER onto ORts could be well described by Langmuir model. In the binary-contaminant system, the existence of AFB1 would bring negative effect to the adsorption of ZER. On the other hand, the adsorption of ZER was in favor of the adsorption of AFB1 molecules. The solution pH had negligible influence on the adsorption process of ORts both in single system and binary system, indicating no desorption occurred when the adsorbents pass through from stomach to intestine as animal feed. This study demonstrates that the received ORts could be a promising adsorbent for detoxication of different mycotoxins in real application.