Adsorption behavior of activated carbon for the elimination of zearalenone during bleaching process of corn oil

Abstract

Zearalenone is a mycotoxin produced by Fusarium species. It frequently contaminates cereals used for foods or animal feeds, especially deposited in crude corn oil. Certain amounts of zearalenone can be removed during refining processes. In this study, we studied the influence of activated carbon and six industial absorbents (zeolite, diatomite, attapulgite, perlite, montmorillonite and activated clay) on the elimination of zearalenone during bleaching process of corn oil and explored the absorption mechanism of activated carbon. Results showed that activated carbon had an excellent adsorption capacity of zearalenone compared with the other six industrial adsorbents. For activated carbon, a high removal rate of zearalenone (exceeding 83%) from heavily zearalenone-polluted corn oil was achieved and the removal rate of zearalenone was kept above 60% after five regeneration cycles. The research on the adsorption mechanism of activated carbon showed that Freundlich adsorption isotherm model and pseudo-second-order kinetic model could well described the adsorption process. The thermodynamic study demonstrated that adsorption process was spontaneous and exothermic. Fourier transform infrared spectroscopy and Raman spectroscopy further revealed that activated carbon was effectively combined with zearalenone via π-π interaction. Thus, activated carbon is an efficient and suitable adsorbent to control the levels of zearalenone during bleaching process of corn oil. This study not only proposed a systematic research scheme for the mechanism study of activated carbon for the elimination of zearalenone in corn oil, but also provided the scientific basis for developing effective methods to eliminate zearalenone in refined vegetable oils.