Development of Lignin-Chitosan-Iron Nanocomposite for Effective Removal of Aflatoxin B1 in Food and Feed Systems

The consumption of contaminated food can lead to several diseases in humans and animals. Aflatoxins are one of the most emerging contaminants in food commodities. In this study, the surface of lignin nanoparticles was functionalized with chitosan (CS) and iron nanoparticles (Fe-NPs) using a novel, simple, cost-effective, and ecological method. The synthesized nanomaterials were tested to remove the aflatoxin B₁ (AFB₁) contamination. Lignin and CS were extracted from coconut coir and shrimp shell waste, respectively. Whereas, Fe-NPs were produced using black tea leaf extract. The structural elucidation of each nanomaterial was explained using UV-Vis spectroscopy, EDX, SEM, XRD, FTIR, and BET analysis. These observations revealed that the produced nanomaterials were spherical with diameters ranging from 60 to 200 nm. The percent removal of AFB₁ was found in the following order: L-CS-Fe > L-CS > LNP > L-Fe > CS. The removal efficacy of L-CS-Fe was > 95% using 1 mg/mL of adsorbent, AFB₁ 100 ng/mL, pH 5, at 37^oC in 75 min. Langmuir isotherm model was well aligned with a maximum adsorption capacity of 160.7 mg/g and monolayer coverage. The adsorption process was spontaneous and endothermic followed by the pseudo-second-order kinetic model. The L-CS-Fe remained reusable and retained its efficacy even after five measured cycles. In conclusion, L-CS-Fe exhibited excellent performance for AFB₁ removal due to its high adsorption and regeneration capability. In addition, it can be applied as a useful and safe adsorbent in naturally contaminated food/feedstuffs.