Separation of soybean oil/n-hexane and soybean oil/n-butane mixtures using ceramic membranes Marcus V. Tres a, ⁎, Jessica C. Racoski a , Marco Di Luccio b , J. Vladimir Oliveira b , Helen Treichel c , Debora de Oliveira b , Marcio A. Mazutti d a Department of Food Engineering, URI Erechim, Erechim, 99700-000 RS, Brazil b Department of Chemical and Food Engineering, UFSC, Florianópolis, 88040-900 SC, Brazil c Federal University of Fronteira Sul, UFFS, Erechim, 99700-000 RS, Brazil d Department of Chemical Engineering, UFSM, Santa Maria, 97105-900 RS, Brazil abstract article info Article history: Received 12 June 2013 Received in revised form 16 January 2014 Accepted 8 February 2014 Available online xxxx Keywords: Soybean oil n-Hexane n-Butane Miscella Ceramic membrane Hollow fiber membrane This study aimed to investigate the separations of mixtures of refined soybean oil/n-hexane, crude soybean oil/n-hexane (industrial miscella) and refined soybean oil/pressurized n-butane using membrane technology. Commercial ceramic membranes with molecular weight cut-offs between 5 and 10 kDa were employed, varying the mass ratios of the oil/solvent, from 1:1 to 1:3 (w/w). Oil rejections up to 100%, total permeate fluxes (oil + solvent) up to 42.97 kg/m 2 h with oil permeate fluxes up to 1.4 kg/m 2 h were obtained. The industrial miscella showed the same behavior observed for the synthetic mixtures presenting an increase in the oil rejection with a de- crease in total permeate flux. In the separation of the oil/n-butane mixtures, higher oil rejections were obtained when compared to the system oil/n-hexane. The results presented in this work indicate the potential applicability of membrane technology in vegetable oil processing and biodiesel industries in the solvent recovery step. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Soybean is an oil seed originating from northern and central China (Missão, 2006). Brazil and the United States of America are the major producers of soybeans in the world, but the introduction of this oilseed in these countries was recent (18th and 19th centuries). Soybean is pri- marily a seed grown for industrial extraction of oil and protein (Erickson & Wiedermann, 1991; Liu, 2000). In conventional extraction plants of vegetable oils, distillation units, and vacuum-operated and other auxiliary equipment using steam or some other form of heat are employed in the processing of oilseeds. A possible thermal degradation of the oil and an incomplete elimination of the solvent, n-hexane, are the major drawbacks of this technology, compared to the technology that uses pressurized fluids as solvents, in addition to the large amount of energy used in these processing steps (Reverchon & Marco, 2006). The n-hexane is a relatively inexpensive solvent and is very effective for extracting nonpolar lipids. However, it is highly volatile and is con- sidered to be toxic to animals and humans, even at low concentrations. Vapors of n-hexane should be monitored during industrial operation of extraction, since it can cause explosions, due to the high flammability. Additionally, if the oil and defatted meal are used in foods, complete removal of the solvent is required (Sparks, Hernandez, Zappi, Blackwell, & Fleming, 2006). The extraction of oilseeds with high added value using compressed gas may present many advantages over conventional solvent (liquid) solvents. Compared with oil extraction using n-hexane, extraction tech- nology using compressed fluids (gases at ambient conditions) presents as the main characteristics the low temperature used and cost reduction in desolventizing. The advantages of using this technology can be sum- marized in three main aspects: 1) maximum preservation of oil quality due to low temperature used, and therefore it is more suitable for extraction of oil or high-value crops with modified lipid composition, 2) maximum preservation of the quality of the cake, with high protein content, and 3) reduction of the total investment and utility cost (Xuede & Liu, 2005). The membrane separation processes often have advantages over conventional separation procedures, which include energy savings in processing, the selectivity of the compounds obtained, the possibility of separation of thermolabile compounds, simplicity of operation of the system and ease of scaling a prototype from laboratory scale to industrial large scale (Habert, Borges, & Nobrega, 2006). The basic pa- rameters for a successful implementation of this technology in oil and fat industry require special attention to the characteristics of feeding the oil/solvent aging/degradation of the membrane, pre-treatment (conditioning), and providing the process conditions, sanitary design, cleaning and disinfection of the membrane (Subramanian, Nakajima, Food Research International xxx (2014) xxx–xxx ⁎ Corresponding author. Tel.: +55 54 35209000; fax: +55 54 35209090. E-mail address: mvtres@uricer.edu.br (M.V. Tres). FRIN-05072; No of Pages 9 http://dx.doi.org/10.1016/j.foodres.2014.02.004 0963-9969/© 2014 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres Please cite this article as: Tres, M.V., et al., Separation of soybean oil/n-hexane and soybean oil/n-butane mixtures using ceramic membranes, Food Research International (2014), http://dx.doi.org/10.1016/j.foodres.2014.02.004