Removal of chromium (III) by two-aqueous phases extraction

Two-aqueous phase extraction of chromium (III) as a solute from their aqueous solutions was investigated using polyethoxylated alcohols (CiEj) as a biodegradable non-ionic surfactant in the presence of anionic sodium dodecylbenzene sulfonate (SDBS). First, the combined effects of chromium and surfactants mixture (anionic and non-ionic) on the cloud point temperature were determined. After this, the phase diagrams of binary systems water-surfactant (NW342 and C(10)E(3)) were traced. According to the given surfactants concentration, the extracted solute reached 98.5% and 60% for NW342 and C(10)E(3), respectively at pH equal to 3. The addition of sodium chloride lowers the cloud point temperature of surfactant where the phenomenon of salting-out was pronounced. Under the optimal extraction conditions, the suggested extraction mechanism is based on chromium species-NW342 non-ionic surfactant micelles solvatation. Since, the prevalence species (93.82%) were Cr(III)(4)(OH)(6)(6+), given by a theoretical calculation using CHEAQS V. L20.1. The first stage regeneration of NW342 surfactant was 27.82% at pH equal to 4. 2(3) factorial designs were employed for screening the factors that would influence the overall optimization of a batch procedure of sorption.