A thorough investigation of the adsorption of metal ions in seawater on d-glucose and its analogues: A theoretical study

d-glucose and its analogues have been studied as potential adsorbents for the removal of Na+, K+, Mg2+ and Ca2+ ions in adsorption desalination studies. Density Functional Theory calculations have been employed to examine the preferential adsorption of these ions at all the available sites of the three chosen substrates. Structure, energy, frontier molecular orbital and natural bond order analyses revealed the nature and strength of the non-bonded interactions between the adsorbate and the adsorbent. Divalent metal ions formed stronger interactions with the substrates than the monovalent metal ions. Molecular electrostatic surface potential analysis helped to understand the charge separation after the metal ion (Mn+) adsorption at the available sites on the substrate. The stability of the studied Mn+-substrate complexes is attributed to non-bonded interactions between the polar heteroatoms on the carbon backbone of the substrate with the positively charged Mn+ ions through electronic charge transfer. These findings can significantly impact the design of new adsorbents for adsorption desalination technology based on naturally available substrates that can be used effectively at ambient temperature. [Display omitted] •Preferential adsorption of divalent (Mg2+ and Ca2+) ions over monovalent (Na+ and K+) ions at various available sites of cellulose, chitosan and chitin monomers.•Interactions occur via the polar heteroatoms on carbon backbone of the substrates.•Charge transfer from lone pair orbital of heteroatom to LP* orbitals of Mn+ ion is observed.•MESP reveals charge separation in the Mn+-substrate complexes•NCI analysis displays strength of interactions between Mn+ and heteroatom at reactive site of substrates