Simulating and Predicting Adsorption of Organic Pollutants onto Black Phosphorus Nanomaterials

Layered black phosphorus (BP) has exhibited exciting application prospects in diverse fields. Adsorption of organics onto BP may influence environmental behavior and toxicities of both organic pollutants and BP nanomaterials. However, contributions of various intermolecular interactions to the adsorption remain unclear, and values of adsorption parameters such as adsorption energies (E-ad) and adsorption equilibrium constants (K) are lacking. Herein, molecular dynamic (MD) and density functional theory (DFT) was adopted to calculate E-ad and K values. The calculated E-ad and K values for organics adsorbed onto graphene were compared with experimental ones, so as to confirm the reliability of the calculation methods. Polyparameter linear free energy relationship (pp-LFER) models on E-ad and logK were developed to estimate contributions of different intermolecular interactions to the adsorption. The adsorption in the gaseous phase was found to be more favorable than in the aqueous phase, as the adsorbates need to overcome cohesive energies of water molecules onto BP. The affinity of the aromatics to BP was comparable to that of graphene. The pp-LFER models performed well for predicting the E-ad and K values, with external explained variance ranging from 0.90 to 0.97, and can serve as effective tools to rank adsorption capacities of organics onto BP.

Automated summary

Layered black phosphorus (BP) has great potential in various fields, but the interactions and parameters of BP adsorption with organics are lacking. In this study, molecular dynamic and density functional theory were used to calculate the energy and equilibrium constants of organics adsorbed onto BP. Gaseous phase adsorption was found to be more favorable than aqueous phase, and the affinity of aromatics to BP was similar to graphene. The established polyparameter linear free energy relationship model effectively predicted the adsorption capacity of organics onto BP.