Pesticide Removal from Aqueous Solutions by Adding Salting Out Agents

Phase segregation in aqueous biphasic systems (ABS) composed of four hydrophilic ionic liquids (ILs): 1-butyl-3-methylimidazolium methylsulfate and 1-ethyl-3-methylimidazolium methylsulfate (CnC1im C1SO4, n = 2 and 4), tributylmethyl phosphonium methylsulfate (P4441 C1SO4) and methylpyridinium methylsulfate (C1Py C1SO4) and two high charge density potassium inorganic salts (K2CO3 and K2HPO4) were determined by the cloud point method at 298.15 K. The influence of the addition of the selected inorganic salts to aqueous mixtures of ILs was discussed in the light of the Hofmeister series and in terms of molar Gibbs free energy of hydration. The effect of the alkyl chain length of the cation on the methylsulfate-based ILs has been investigated. All the solubility data were satisfactorily correlated to several empirical equations. A pesticide (pentachlorophenol, PCP) extraction process based on the inorganic salt providing a greater salting out effect was tackled. The viability of the proposed process was analyzed in terms of partition coefficients and extraction efficiencies

Environmentally Benign Sequential Extraction of Heavy Metals from Marine Sediments

An environmentally friendly heavy metals remediation process from polluted marine sediments is proposed. The efficiency of three organic and inorganic salts (ammonium acetate, ammonium nitrate, and sodium potassium tartrate) to salt out these pollutants was ascertained in sediment washing waters containing nonionic surfactants. The immiscibility regions were correlated by means of three known models, and the experimental data were interpreted in the light of thermodynamic parameters such as Gibbs free energy of hydration and molar entropy of hydration. The proposed process was applied to model aqueous solutions containing two representative heavy metals (zinc and copper). The viability of the suggested strategy was checked in real contaminated marine sediments by including a sequential treatment: marine sediment washing–contaminant extraction, which led to total remediation values higher than 80% for copper and 90% for zinc

Testing True Choline Ionic Liquid Biocompatibility from a Biotechnological Standpoint

This work is a first approach to demonstrate the viability of a quantitative biotechnological removal of choline chloride from aqueous effluents. Despite the much vaunted biocompatibility of this ammonium-based ionic liquid, it was demonstrated (both by an ad-hoc F test recommended by the Organization for Economic Co-operation and Development and flask assays) that different microorganisms able to degrade persistent chemicals were not able to metabolize it. Only a halophilic bacterium, recently isolated in our research group (Halomonas sp.), exhibits the enzymatic mechanism to catalyze the cleavage of the ionic liquid cation. The biotechnological process was optimized by carefully cherry-picking the carbon source and proposing an adaptation strategy. In this way, a complete choline removal was attained in less than 24 h when the surfactant Tween 80 was added to the ionic liquid-containing aqueous effluent