Environmental implications of Si2BN nanoflakes in pharmaceutical pollutant detection and removal: insights from first-principle calculations

Pharmaceutical pollutants, such as carbamazepine (CBZ), are emerging contaminants that pose significant environmental and health risks due to their persistence in aquatic ecosystems and incomplete removal by conventional wastewater treatments. This study leverages density functional theory (DFT), a gold-standard computational quantum mechanical modeling method, to evaluate the efficacy of Si₂BN nanoflakes-a novel two-dimensional material-for CBZ adsorption and detection. Our first-principles calculations reveal thermodynamically stable interactions between CBZ and Si₂BN, with adsorption energies of - 0.83 eV (edge) and - 0.82 eV (surface). The material's responsive optical behavior is quantified through time-dependent DFT, showing a 138 nm blueshift in UV-Vis spectra upon adsorption, a hallmark of its sensing capability. Furthermore, DFT-calculated charge transfer (0.04-0.06 e) and Fermi-level shifts (- 4.52 to - 4.69 eV) underscore Si₂BN's enhanced electronic properties, enabling selective pollutant detection. By bridging atomic-scale insights (bond distortions, orbital hybridization) with macroscale environmental applications, this work demonstrates how DFT-guided design unlocks Si₂BN's dual functionality as a scalable adsorbent and optical sensor. These findings provide a quantum-mechanical foundation for advancing Si₂BN nanoflakes as a scalable, stable, and effective material for addressing pharmaceutical pollutants in water, offering a sustainable alternative to conventional methods plagued by secondary contamination risks.