Journal of Magnetism and Magnetic Materials 272–276 (2004) 2413–2414 Intensification of the process of sorption of copper ions by yeast of Saccharomyces cerevisiae 1968 by means of a permanent magnetic field Svetlana Gorobets a, *, Oksana Gorobets b , Anatoliy Ukrainetz a , Taisiya Kasatkina c , Irina Goyko a a National University of Food Technologies, Vladimirskaya 68, Kiev 01033, Ukraine b Institute for Magnetism NAS of Ukraine, Vernadskogo Blvd. 36-b, Kiev 03142, Ukraine c Institute for Microbiology and Virology, Akademika Zabolotnogo St. 154, Kiev 03627, Ukraine Abstract Possibility to replace mechanical stirring by magnetic field-induced one was shown for intensification of yeast biosorption and cementation. Combined method of metal ion recover, including Cu ion sorption by yeast Saccharomyces cerevisiae and Cu cementation on a surface of a steel matrix, is tested in a case of magnetic field- induced stirring. r 2003 Elsevier B.V. All rights reserved. PACS: 87.40 Keywords: Biosorption; Yeast; Magnetic field; Magnetohydrodynamic stirring 1. Introduction A set of methods is traditionally used and developed for removal of metal ions from water solutions including methods based on cementation and biosorption pro- cesses. Yeast biomass plays an important role in investiga- tions in the field of biosorption [1]. Yeast biomass can be obtained in great quantities as waste products of many fermentation processes. Besides, yeast can grow in solutions with high concentration of heavy metals. Yeast can accumulate metals in biomass [1]. While the ion exchange resins which are widely used to purify wastewater are 10 times more expensive than biosor- bents [2]. Temperature, ion forces, metal concentration in the solution magnetic and electromagnetic field, pH and other chemical and physical factors influence on the yeast biosorption [1]. Usually biosorption is used together with other purification methods. It is well known that stirring leads to the intensifica- tion of many processes including biosorption, cementa- tion, etc. That is why mechanical mixers are widely applied to intensify biosorption and cementation. However, mechanical stirring is not the only possible stirring method for water solutions. For example, magnetohydrodynamic convection was revealed in electrolytes in combined electric and magnetic fields [3]. Moreover, the stirring effect, induced by a steady magnetic field, was revealed in the vicinity of metal surfaces in electrolytes when the external electric field was not applied [4–6]. That is why the aim of the present work is testing the possibility to intensify a combined method of Cu ion removal from a solution by means of magnetic field-induced stirring instead of mechanical one. The combined method consists of simultaneously organized cementation of Cu on the steel matrix surface and Cu ion biosorption by yeast. ARTICLE IN PRESS *Corresponding author. Institute for Magnetism, Vernads- kogo St. 36-b, Kiev 3142, Ukraine. Tel./fax: +38-044-220-9355. E-mail address: gor@usuft.kiev.ua, gor@nuft.kiev.ua (S. Gorobets). 0304-8853/$-see front matter r 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.jmmm.2003.12.840