Pore characteristics influence on MOFs adsorption of pyrethroid pesticides revealed by GCMC simulation and DFT calculation

Abstract

The adsorptive behavior 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 simulation and DFT calculation to investigate pore characteristics influences on adsorption performance. Therein, based on the structural characteristics of PYs molecules, MOFs were constructed using organic ligands with similar structures, featuring the same number and type of aromatic rings, to minimize variations in host-guest interactions. It was found out that for both bioresmethrin and lambda-cyhalothrin, the adsorption capacities of four MOFs were ranked as IRMOF-16>UiO-68>Quin-Fe-TPTC>NU-1400. 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) of MOFs exceeds 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 the cavities, PYs primarily engage in π-π interaction and CH-π interaction with adjacent ligands. A significant number of PYs occupy these cavities, stabilized by intermolecular interactions among themselves. These findings reveal the correlation between pore characteristics and MOFs adsorption performance, providing valuable guidance for rational design of MOFs for PYs adsorption in food safety application