DFT insight into Cd2+, Hg2+, Pb2+, Sn2+, As3+, Sb3+, and Cr3+ heavy metal ions adsorption onto surface of bowl-like B30 nanosheet

Abstract

Contamination of water resources by heavymetal ions, is a drastic environmental concern. In this study, the interaction of Cd2+, Hg2+, Pb2+, Sn2+, As3+, Sb3+, and Cr3+ metal ions onto surface of the bowl-like B30 nanosheet was scrutinized based on density functional theory (DFT) calculations. Adsorption energy (Eads) values revealed that the As3+ interacted better with bowl-like B30 nanosheet in comparison to other metal ions, having adsorption energy values of −299.57 and −628.56 kcal mol−1in the gas phase and aqueous media, respectively. However, Hg2+, Pb2+, and Sn2+ metal ions physically adsorbed onto bowl-like B30 nanosheet in the gas phase because of their much less value of adsorption energy. The sign of adsorptionGibbs free energy change(ΔGads) and adsorption enthalpy change (ΔHads) values for all complexes was found to be negative in the gas phase and aqueous media, which indicated that the adsorption process is spontaneous and exothermic. Frontier molecular orbital (FMO) analysis exhibited a decrease in the HOMO-LUMO energy gap of studied complexes, boosting the electrical conductivity of these complexes. Natural bond orbital (NBO) analysis and charge decomposition analysis (CDA) revealed donor–acceptor charge transfer interactions in the complexes. The UV–vis results depicted that λmax was red-shifted during interactions of meal ions with bowl-like B30 nanosheet. Finally,quantum theoryof atoms in molecules (QTAIM) exhibited that the interaction between As3+ metal ion and the nanosheet is covalent in nature, while the other metal ions have predominantly electrostatic with partially covalent and non-covalent characters. The theoretical results of the study represented the feasibility of applying bowl-like B30 nanosheet to remove heavy metal ions, especially As3+ and providing information for experimental researchers to treat wastewaters.