Contact
    Start Publications Toward green flotation: Interaction of a sophorolipid ...
    ←  Publication Finder
    Attension

    Toward green flotation: Interaction of a sophorolipid biosurfactant with a copper sulfide

    Year: 2021

    Journal: J. Colloid Interface Sci., Volume 585, MAR, page 386–399

    Authors: Dhar, Priyanka; Havskjold, Hakon; Thornhill, Maria; Roelants, Sophie; Soetaert, Wim; Kota, Hanumantha Rao; Chernyshova, Irina

    Organizations: Research Council of Norway (NFR), FRINATEK Project [274691]; Department of Geoscience and Petroleum, NTNU

    Keywords: Copper sulfide; Glycolipid; Bipolar surfactant; Foam flotation; Metal extraction; FTIR

    The United Nations' Sustainable Development Goals have sparked growing interest in biosurfactants from many surfactant-loaded industries including those utilizing froth flotation for mineral separation. However, the interaction of biosurfactants with mineral surfaces is currently poorly understood. We bridge this gap by studying adsorption of a yeast-derived bola acidic sophorolipid (ASL) biosurfactant on djurleite (Cu1.94S). The methods used include Hallimond flotation, contact angle, adsorption isotherm, zeta potential, leaching measurements, and X-ray photoelectron spectroscopy (XPS). To facilitate the interpretation of the adsorption results, we characterize the activity of ASL at the air-water interface and measure its critical micelle concentration (CMC) at different pH using static surface tension. We find ASL to be a multifunctional surfactant with an unusual, pH-sensitive interfacial behavior. At the air-water interface, ASL is most active at pH 8, while its CMC goes through minimum as low as 40 lM at pH 7. The surfactant adsorption at the djurleite-water interface makes the sulfide surface hydrophilic at acidic pH and hydrophobic at neutral and basic pH. In addition, ASL has strong affinity to copper sulfide and demonstrates metal leaching properties. Finally, ASL demonstrates detergency properties. We offer a mechanistic interpretation of these findings. Our results provide a basis for the application of acidic glycolipids in froth flotation and have implications for their application in ion separation using hydrometallurgical routes, as well as for the chemical stability of metal sulfides in environmental systems. (C) 2020 The Authors. Published by Elsevier Inc.
    View publication