Localized Surface Plasmon Resonance, SERS, and Density of State Characterization of Phenols for Wastewater Remediation

Phenolic compounds pose a significant risk to the quality of water since they often remain persistent across the water supply chain. For the urban and peri-urban populations that leverage traditional water treatment approaches like boiling and filtration, phenols remain a key challenge since they are persistent micropollutants. In this work, the removal of these compounds has been demonstrated with the help of density functional theory, which, unlike experimental approaches, is less laborious and affordable. Localized surface plasmon resonance (LSPR), surface-enhanced Raman (SERS), and density of states were used to achieve label-free detection of the said molecule. The shifts in the plasmon band, as well as the Raman scatter bands, can be measured against different concentrations for trace detection of phenols and other contaminants. Raman scatter bands at 1120 cm⁻¹, 1192 cm⁻¹, 1345 cm⁻¹, and 1561 cm⁻¹ emerged as key marker bands for spectral characterization of phenol molecules. Spectral shifts and intensity changes in such bands can be monitored for effective environmental remediation. Similarly, changes in band gap energy were monitored with the help of the density of state (DOS), and the charge distribution studies were carried out with the help of Mulliken analysis, demonstrating that there is a general reduction in the band gap after adsorption, with oxygen being the most electronegative element. Such changes in band gap and electronegativity studies can be used in the future for sensing of environmental contaminants.