Self-templating construction of flower-like mesoporous magnesium silicate composites from sepiolite for high-efficiency adsorption of aflatoxin B1

Abstract

The rational design and fabrication of mesoporous materials with highly exposed surface area are of great significance to address water pollution problems caused by mycotoxins. In this work, a facile self-templating strategy was developed to construct flower-like mesoporous magnesium silicate composites (MMSCs) by subjecting sepiolite to acid bleaching process, followed by hydrothermal reaction. The effect of hydrothermal time on the microstructures and specific surface areas of MMSCs were investigated, and the possible formation mechanism of MMSCs was proposed. The MMSCs synthesized at hydrothermal time of 12 h showed a well aflatoxin B1 (AFB1) adsorption capacity, and the maximum adsorption capacity, calculated from the Langmuir model, was 21.26 mg/g. The high adsorption capacity was mainly attributed to the synergistic effect of flower morphology and mesoporous structure, providing high surface area, and consequently exposing more available adsorption sites (e.g., Si-O-Mg, Mg-OH, and Si-OH), which favored bonding with AFB1. Density functional theory (DFT) calculations revealed that the mechanisms of AFB1 adsorption onto MMSCs were mainly electron donor-acceptor interaction and hydrogen bonding. The strategy proposed here can provide a new avenue for the design of mesoporous materials with high surface area, and resulting materials are promising adsorbents for adsorption of AFB1.