Studies on removal of pb ii from aqueous solution and industrial effluents using green solvent

Abstract

Heavy metal pollutants are one of the nettled problems throughout the world due to their high toxicity and non-biodegradability. Among them, lead(II) is the major priority toxic pollutant that gets involved in the environment through industrial and technological applications, thus resulting in antagonistic effects among human beings. The acceptable limit of Pb(II) in industrial effluents is 0.1 ppm and in drinking water is 0.01 ppm. With the number of environmental legislations and regulations having increased during recent years, some specific regulations have been put forth for the treatment of contaminated water containing metal ions for a safer environment. Besides, the increasing demand for lead production due to their usage in our daily life leads to more research that incorporate efficient and environment-friendly solvents in the recovery of metals. newlineIn the present investigation, 25 halogen-free ionic liquids from the combination of five cations such as 1-butyl-3-methylimidazolium [BMIM]+, 1-pentyl-3-methylimidazolium [PMIM]+, 1-hexyl-3-methylimidazolium [HMIM]+, 1-heptyl-3-methylimidazolium [HEPMIM]+, and 1-octyl-3-methylimidazolium [OMIM]+, and five anions, including butyl sulfate [BUSO4]-, pentyl sulfate [PENSO4]-, hexyl sulfate [HEXSO4]-, heptyl sulfate [HEPSO4]- and octyl sulfate [OCTSO4]- were prescreened using the COSMO-RS model. The quantum chemical descriptors such as Highest Occupied Molecular Orbital (HOMO) energy, Lowest Unoccupied Molecular Orbital (LUMO) energy, HOMO-LUMO energy gap, electrophilicity index, electronegativity, global hardness and global softness were predicted for the studied molecules. newline