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

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:585

Article

Dhar, Priyanka¹  Havskjold, Hakon¹  Thornhill, Maria¹  Roelants, Sophie^2,3  Soetaert, Wim^2,3  Kota, Hanumantha Rao¹  Chernyshova, Irina¹ 

[1] Norwegian Univ Sci & Technol NTNU, Dept Geosci & Petr, NO-7031 Trondheim, Norway

[2] Bio Base Europe Pilot Plant, Rodenhuizekaai 1, B-9042 Ghent, Belgium

[3] Univ Ghent, Fac Biosci Engn, Dept Biotechnol BW25, Ctr Ind Biotechnol & Biocatalysis InBio Be, Coupure Links 653, B-9000 Ghent, Belgium

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

DOI  :  10.1016/j.jcis.2020.11.079

来源: Elsevier

【 摘 要 】

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.

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