J. Appl. Eng. Sci. Technol. (2018) 4(1): 1-5  Corresponding author. E-mail address: hasseine@yahoo.fr This work is licensed under a Creative Commons Attribution 3.0. License (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/ JOURNAL OF APPLIED ENGINEERING SCIENCE &TECHNOLOGY | JAEST - ISSN 2352-9873 (PRINT) |SECTION E: CHEMICAL AND PROCESS ENGINEERING Available online at http://revues.univ-biskra.dz/index.php/jaest fst Recovery of acetic acid from aqueous solutions using salting effect Ahleme Aidaoui, Abdelmalek Hasseine  Laboratoire de Génie civil et Hydraulique, Développement durable et Environnement, Université de Biskra, B.P. 145 R.P. 07000, Biskra, Algeria Received 16 June 2016 Published online: 17 May 2018 Abstract: The application of salting effect to isolate an organic acid, particularly Acetic acid, from aqueous solution is reported. In fact the presence of a salt can influence the solubility of a compound by either increasing it or decreasing it, leading to Salting-in and Salting-out, respectively. The addition of a salt in an aqueous solution introduces ionic forces which affect liquid-liquid equilibrium and which influence directly the distribution coefficient of the solute. The effect of NaCl and Na2SO4 on the liquid-liquid equilibrium data of the ternary system (Water+ Acetic Acid+ Dichloromethane) at a temperature of 293.15 K and an atmospheric pressure is studied experimentally in this work. The mass fractions of salt in the total mixture are 5%, 10% and 20%. It is noted that the equilibrium between phases is modified preferably to the extracted phase and the salting-out in the case of sodium sulfate is more significant than the effect of chloride. Keywords Acetic acid recovery Liquid-liquid equilibrium Salting effect Sodium chloride Sodium sulfate © 2017 The authors. Published by the Faculty of Sciences & Technology, University of Biskra. This is an open access article under the CC BY license. 1. Introduction Acetic acid is one of the simplest and most widely used carboxylic acids having many important chemical and industrial applications. Total worldwide production of acetic acid is about 6.5 million tonnes per year; out of which about 5 million tonnes are produced by methanol carbonylation process and by bacterial fermentation and the remaining 1.5 million tonnes by recycling (Shin et al. 2009). The recovery of carboxylic acids from either fermentation broth or low titer wastewater presents a significant challenge. A great deal of effort has been made in developing feasible and economic method for recovery of carboxylic acids. For example, the precipitation with calcium hydroxide or calcium oxide, followed by filtration, acidification and crystallization, has been employed as the main recovery method, although it has great difficulty and low yield. The others acid recovery processes are available, including electrodialysis, esterification, chromatography, extractive fermentation and solvent extraction (Yang et al. 1991). Among them, Liquid-liquid extraction using aqueous two-phase systems (ATPS) has been demonstrated to be a highly efficient separation technique for small organic species (Fu et al. 2015). The presence of inorganic salt changes the phase equilibrium behaviour of a mixture significantly. This phenomenon is often referred to as the salting in or salting-out effect (Singh et al. 2006). It can be used to optimize separation processes such as rectification to shift the azeotropic conditions, extraction to alter the miscibility gaps and also absorption and fractional crystallization to change the distribution coefficients. The salt effect is also important in biological processes such as purification of proteins, enzymes, nucleic acids, and others (Hasseine et al. 2009). During recent years, attempts have been made to generate the reliable as well as reproducible experimental data for systems containing salts. Typically, the salting-out effect on the (liquid + liquid) equilibria systems has been the topic of investigation in the separation processes using the preferential organic solvents (Aznar et al. 2000). The study of efficiently separating and recovering Acetic acid from aqueous solutions is an important significance on industry and environmentally sustainable development. Many research groups in different countries are working in this field and some methods are proposed in the literature (Vakili-Nezhaad et al. 2004; Koga et al. 1978; Watanabe et al. 1985; Chand et al. 1994; Sano et al. 1995; Cockrem 1996; Baniel 1998 ; Saha et al. 2000; Demiral et al. 2003; Singh et al. 2006). Accordingly, the present research is aimed to recover acetic acid from aqueous solution using salting effect on the solvent extraction method. In this work, effect of sodium chloride and sodium sulfate with different content (5%, 10% and 20%) on the liquid-liquid equilibrium data of (water+ acetic acid+ DCM) system is investigated. The experimental results were correlated based on the Othmer-Tobias correlation. 2. Experimental 2.1. Chemicals and apparatus Acetic acid and Dichloromethane were obtained from Biochem (p.a.> 99.5%) and used without further purification. The sodium chloride and sodium sulfate was provided from Merck with purity 99%. Distilled water was prepared using GFL 2001/4 distillation unit. The quaternary system was mixed with a magnetic stirrer (Nahita model 690 type), and heated at a constant temperature in the brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Biskra University Journals