Use of aqueous two-phase PEG-salt systems for the removal of anionic surfactant from effluents

• Published in: Journal of environmental management 2017-08, Vol.198 (Pt 1), p.43-49
• Main Authors: Murari, Gabriella Frade, Penido, Jussara Alves, da Silva, Heriveltom Morais, Baêta, Bruno Eduardo Lôbo, de Aquino, Sérgio Francisco, de Lemos, Leandro Rodrigues, Rodrigues, Guilherme Dias, Mageste, Aparecida Barbosa
• Format: Article
• Language: English
• Subjects: Benzene Derivatives; Green chemistry; Linear alkylbenzene sulfonate; Partition; Polyethylene Glycols; Polymer-surfactant interaction; Polymers; Sodium Chloride; Surface-Active Agents; Water; Water Pollutants, Chemical
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2017.04.046

Linear alkylbenzene sulfonates (LAS) are synthetic anionic surfactants that are extensively used in many industries. As a result, large volumes of effluents containing high levels of these compounds are discharged into water bodies, causing risks to aquatic flora and fauna. Then, there is a need for environmentally safe and economically viable technologies for the removal of LAS from aqueous matrices. The present work evaluates the use of aqueous two-phase systems (ATPS) composed of PEG and sulfate salts for this purpose, considering the effects of tie line length (TLL), molar mass of polymer, and type of cation-forming salt on the partitioning behavior of LAS. All the LAS partition coefficient (KLAS) values were greater than unity, and the LAS extraction efficiencies (%ELAS) were higher than 97%. The system consisting of PEG 1500 + (NH4)2SO4 + H2O provided the highest KLAS (1083.34) and %ELAS (99.9%), indicating that the method provided good extraction of LAS to the top phase. This system was applied using a real effluent sample in laboratory-scale experiments as well as in bench-scale batch trials. The results obtained at the laboratory scale showed %ELAS values greater than 98%, while the best KLAS value obtained in the batch experiments was 8.50 (±1.75) (%ELAS = 78.17%). These values demonstrated the potential of ATPS for the removal of LAS from industrial effluents. [Display omitted] •Green Techniques for Linear alkylbenzene sulfonate (LAS) removal from effluents are in demand.•Aqueous two-phase systems employing sulfate salts with polymer were evaluated for LAS removal.•Partition studies of LAS were carried on laboratory scale, as well on a semi-pilot plant scale.•The optimized system gave satisfactory extraction efficiency of anionic surfactant (%ELAS).•Removal of LAS from a real effluent sample was attained with an efficiency of 78.17%.