Mahmood Niad

Background: Computational chemistry is based on mathematical and physical concepts. The main goal is to get optimal structures, physicochemical properties, and reactivity of chemical compounds using theoretical methods. The density functional theory determines the properties of the system based on the electron density. Aim: The theoretical investigation of the absorption of chromate ions on some bioactive molecules of ginger extract, i.e., gingerol, shogal, and beta-pinene. Methodology: The structure of gingerol, shogal, and beta-pinene was calculated and optimized in the presence and absence of chromate ions. The structures were drawn by GaussView 6 software and were optimized by Gaussin 09. Both M062x/SDD and B3LYP/6-31G levels of theory were used. The structural, geometrical, and electronic properties of the molecules and the shape and energy of the frontier orbitals were studied. Natural bonding orbital assessed the origin of the interactions. Also, the reactivities of different atoms was calculated and compared using molecular and theoretical electrostatic potentials of atoms in molecules. Results: Ginger extract can be used as an adsorbent for the removal of chromate ions. It was found that the absorption of chromate by ginger is physical. Conclusions: The gingerol, shogal, and beta-pinene molecules in the ginger extract were selected to investigate the absorption of chromate ions. Gingerol showed the highest and beta-pinene showed the lowest tendency to absorb the chromate ion. The biosorption was spontaneous and exothermic.