Influence of the pore characteristics of MOFs on the adsorption of pyrethroid pesticides revealed by GCMC simulations and DFT calculations

Abstract

The adsorptive characteristics of two typical pyrethroid pesticides (PYs), bioresmethrin and lambda-cyhalothrin, by four MOFs (IRMOF-16, UiO-68, Quin-Fe-TPTC, and NU-1400) were revealed by GCMC simulations and DFT calculations to investigate the influence of pore characteristics on adsorption performance. Therein, based on the structural characteristics of PY molecules, MOFs were constructed using organic ligands, with similar structures and featuring the same number and type of aromatic rings, to minimize the variations in host–guest interactions. It was found that for both bioresmethrin and lambda-cyhalothrin, the adsorption capacities of the four MOFs were ranked as IRMOF-16 > UiO-68 > Quin-Fe-TPTC > NU-1400. The MOFs with cage-like cavity structures facilitate adsorption more effectively than those with channel-type structures. The sealed pore cage structure facilitates the capture of molecules rather than merely their accumulation within the pore volume. When the pore limiting diameter (PLD) value of MOFs is greater than the dynamic diameter of PYs, the largest specific surface area, pore volume and void fraction of MOFs are directly proportional to their adsorption capacity, respectively. Additionally, PYs are primarily located within the hydrophobic cavities of MOFs. Within these cavities, PYs primarily engage in π–π interactions and CH–π interactions with the adjacent ligands. A significant number of PYs occupy these cavities and are stabilized by intermolecular interactions among themselves. These findings reveal the correlation between the pore characteristics and adsorption performance of MOFs, providing valuable guidance for the rational design of MOFs for the adsorption of PYs in food safety applications.