Palygorskite Clay Supported With EDTA for the Selective Removal of Aflatoxins From Peanut Oil

Palygorskite clay (Pal) treated with ethylenediaminetetraacetic acid (EDTA) was employed as an innovative adsorbent to remove aflatoxins from edible oils. The structural characteristics of EDTA-modified Pal adsorbent were analyzed using characterization techniques, such as scanning electron microscopy, nitrogen adsorption/desorption experiments, Fourier transform infrared spectroscopy, and x-ray diffraction patterns. The modified Pal exhibited superior adsorption performance, at 0.3% of the adsorbent, the aflatoxin concentration of peanut oil (82.57 µg/kg) could be reduced to below the European Union limit value (≤4 µg/kg). The removal of AFB1 by EDTA-modified Pal was as high as 98.74%, an enhancement of 13.06% compared to raw Pal. Nutrient components were also analyzed, and the retention of tocopherols and sterols in the oil treated with modified Pal increased by 6.36% and 13.67%, respectively, which suggests the prepared composite adsorbent had high selectivity. Finally, the adsorption process was analyzed using adsorption isotherms, kinetics, and thermodynamics. The process fitted better with the Langmuir model and the pseudo-second-order kinetic model, indicating that the adsorption process was mainly chemisorption. Thermodynamic results showed a spontaneous endothermic process. This research provided a novel idea for developing new adsorbents with high selectivity and low cost.