In-situ preparation of palygorskite-montmorillonite materials from palygorskite mineral via hydrothermal process for high-efficient adsorption of aflatoxin B₁

Due to the threats of mycotoxin-contaminated animal feeds to livestock farming, food safety and human health, Palygorskite-Montmorillonite (Pal-Mt) materials with different functional groups and microstructures have been studied as an effective mycotoxin adsorbent. In this study, Pal-Mt materials were controllably regulated from Pal mineral via hydrothermal process by adjusting the hydrothermal temperature. Along with the increase of hydrothermal temperature, the microstructure of Pal showed a gradual transformation from fiber to layer, which led to a fiber-layered structure. Batch aflatoxin B-1 (AFB(1)) adsorption experiments were conducted at different conversion rates of Pal. The optimized Pal-Mt with 50% conversion of Pal exhibited satisfactory adsorption capacity of 13.17 mg/g and removal rate of 95.65% and 91.33% (only 33.09% and 26.27% for Pal) from 2 mg/L of AFB(1) phosphate buffer solution at pH 3.5 and 6.5, respectively. The increasing adsorption capacity was mainly attributed to the synergistic effect of cations in the interlayer of Mt and the high specific area of Pal, resulting in a larger proportion of available adsorption sites (e.g., Ca2+, -OH), which favored bonding with AFB(1) molecules. This work provides a new material regulated from abundant Pal mineral, which is effective and promising for adsorption of AFB(1).