TD-DFT calculation, equilibrium and kinetic adsorption study of removal of rose bengal dye by poly vinyl alcohol as a synthetic polymer adsorbent hybrid blend

Abstract

Spectrophotometric study of the efficacy of the synthetic polymer such as polyvinyl alcohol in the removal of the dye Rose Bengal (RO) was examined. Different contact times, starting dye concentrations, adsorbent doses, dye solution temperatures, and pH values were tested. Density functional theory (DFT) with functional B3LYP and Hartree-Fock (HF) were used to investigate the optimal geometries, vibrational wavenumbers, vibrational band intensities, and atomic charges of 9VC. The researchers contrasted theoretical predictions for the basic vibrational modes with actual measurements. Using the functional B3LYP of DFT, we analyzed the hybrid organic dye (PVA+RO)HB such as the shape of geometry, electronic configuration, the capacity of polarizability, and second-order hyperpolarizability. The time-dependent density functional theory (TD- DFT), linked to a variety of hybrid functionals, was used in order to conduct research on the electronic absorption spectrum. Good agreement was found between the correlation coefficient values obtained from the Langmuir and Freundlich isotherm models, which were used to characterize the adsorption equilibrium. Pseudo-first-order kinetics was the best fit for the data on RO adsorption onto PVA. The values of enthalpy change and free energy change are negative and these confirm that our study concluded the exothermic and adsorption mechanism was spontaneous, respectively. The adsorption capacity was found to increase with increasing temperature. So, the kinetic parameters were evaluated from the temperature dependence of the adsorption capacity using the method of least squares.