Liquid–Liquid Phase Equilibria of Aqueous Biphasic Systems Based on Glycerol Formal: Application on Tetracycline Recovery from Water

Abstract

Biopharmaceuticals are commonly present in relatively low concentrations in aqueous solutions, making their detection and purification detrimental. In this work, we used novel aqueous biphasic systems based on glycerol formal to extract an important antibiotictetracycline. We report cloud points (solubility curve) and tie-lines for three ternary systems, containing glycerol formal (GF), water and inorganic salt (either K3PO4, K2HPO4 or K2CO3) at constant temperature of 298 K and at 0.1 MPa. The tie-line data of these ternary systems were correlated using the non-random two-liquid (NRTL) model and binary interaction parameters of activity coefficients were estimated. The experimental and correlated tie-line data were compared in terms of average root mean square deviation and showed satisfactory agreements. The partition coefficients of tetracycline between two phases were measured and corresponding extraction efficiencies were calculated. The maximum value of partition coefficient was 1551 for the system containing K3PO4, followed by values of 1145 and 927 for systems containing K2CO3, and K2HPO4, respectively. The calculated extraction efficiencies were very highgreater than 98.8%, demonstrating high potential for using aqueous biphasic systems, which are based on glycerol formal, for separation and purification process.

Extraction of antibiotics using aqueous two-phase systems based on ethyl lactate and thiosulphate salts

“…The highest obtained value of partition coefficient for tetracycline is comparable with literature values of 7 -12 in ATPS composed of ethanol and (NH4)2SO4 [31] and higher than 0.9 -6.7 for ATPS composed of PEG and various cholinium-based salts [18]. In general, significantly higher partition coefficients for tetracycline were previously reported for ATPS based on ionic liquids ranging from 34 to 165 [32] and on glycerol formal ranging from 74 to 1522 [26].…”

“…Cloud points of the ternary mixtures containing ethyl lactate, water, and salt (K2S2O3 or Na2S2O3 or (NH4)2S2O3) were determined by the titration method at a constant temperature of 298.2 K and at a pressure of 0.1 MPa as described in our previous work [26]. Binary mixtures containing various known compositions of salt and water were gravimetrically prepared in septum-sealed conical glass vials equipped with a magnetic stirrer and immersed in a temperature-controlled bath (Thermo Scientific) heated with SAHARA SC150 S19T circulator with a stability of 0.05 K. The transparent acrylic bath walls allowed full visualization of the mixture content.…”

Salting-Out-Assisted Liquid–Liquid Extraction for Nicotine from Its Aqueous Solutions

“…The empirical equation, suggested by Merchuk and colleagues, is correlated with the experimental binodal data as follows where W nicotine and W salt are the mass fractions (overall composition) of nicotine and salt in the aqueous solution, respectively, and a , b , and c are the fitting parameters, which are obtained by nonlinear regression (least squares). This equation has been successfully used in other biphasic systems. − …”

Pseudoternary Systems of Deep Eutectic Solvents + tert-Butanol + Water at T = 288.15 K, 298.15 K, and 308.15 K: Liquid–Liquid Equilibrium and Ability for Syringic Acid/Eugenol Separation

“…As far as we know, aqueous biphasic systems (ABS), consisting of large amounts of water, were highly suitable for the construction of liquid–liquid extraction systems resulting from mild extraction conditions, high mass transfer efficiency, and easy operation. − The phase-forming components of ABS were mainly constituted by polymers and polymers, salts, alcohols, or ionic liquids (IL). For instance, Li et al reported that the extraction efficiency of syringic acid was up to 96.66% with the use of the IL/salts-based ABS.…”