Removal Capacity and Mechanism of Modified Chitosan for Ochratoxin A Based on Rapid Magnetic Separation Technology

Ochratoxin A (OTA) exposure in food is very dangerous to human health. Therefore, the development of a fast and efficient technique for OTA removal has become an urgent research topic in the field of food safety. Nano Fe₃O₄ modified chitosan nanocomposite (nano-Fe₃O₄@CTS) was synthesized as a rapidly separable and safe adsorbent and was used to adsorb OTA in wine. FT-IR, XRD, and VSM characterization methods indicated that chitosan was successfully modified by Fe₃O₄ and exhibited good magnetism. The adsorption and kinetics isotherms between OTA and nano-Fe₃O₄@CTS were studied by the Langmuir equation and the pseudo-second order kinetics equation. The mechanism of OTA adsorption on nano-Fe₃O₄@CTS nanoparticles was the combined effect of physical adsorption and chemisorption. The negative <i>ΔH°</i>, <i>ΔG°</i> and <i>ΔS°</i> values proved that the adsorption was a spontaneous and exothermic process. Nano-Fe₃O₄@CTS with a high maximum adsorption capacity of 5018.07 ng/g at 25 °C can rapidly separate the matrix immobilized OTA from wine, and to a certain extent retains some of the wine quality after OTA removal.