Extraction of citric acid from aqueous solutions with Alamine 336: equilibrium and kinetics

Abstract

Citric acid is one of the organic acids for which the world market is growing every year. This article describes equilibria and kinetic studies for the extraction of citric acid by Alamine 336 with methyliso-butylketone (MIBK) as diluent. The theory of extraction accompanied by a chemical reaction has been used to obtain the intrinsic kinetics of extraction of citric acid by Alamine 336 in MIBK. The reaction has been found to be first order in both Alamine 336 and citric acid with a rate constant of 0.013 m 3 kmol −1 s −1 .

Modeling and Optimization of Reactive Extraction of Citric Acid

“…Several studies can be found on the reactive extraction of citric acid using the nitrogen-based extractants such as N -substituted alkyl amides, long chain (about 8–12 carbon atoms) alkyl amines, ,− and so forth. They have reported extraction efficiency as high as 90% using the tertiary amines diluted in active diluents. − Studies on the reactive extraction of citric acid related to equilibrium, ,− kinetics, − effects of pH, back extraction, etc., can be found in the literature. Different modeling approaches have also been reported; for example, a mathematical model was obtained by Bizek et al , using the correlation between solvatochromic properties of diluents .…”

Reactive Extraction of Citric Acid Using Different Extractants: Equilibrium, Kinetics and Modeling

“…Both the partitioning coefficient (P) and dimerization constant (D) of MIBK were found to be around 0.152 and 0.795 that resulted in a low distribution coefficient (K D = 0.175). 10 had reported distribution coefficient of 67.147 (E = 98.5 %) using Alamine 336 diluted in MIBK. The extraction efficiency calculated in this work is in good agreement with the literature.…”

“…The extraction efficiency calculated in this work is in good agreement with the literature. 10,12 The stoichiometry of acid:extractant complex was estimated for chemical extraction of citric acid for all three extraction systems (A336, TBP, and TOA; diluted in MIBK). For TBP and A336, loading ratios (Z) were obtained to be low (Z<0.5), thus, only (1:1) acid:extractant complex formation was assumed.…”

“…Doubtlessly, active diluents provide a better solvation media to the carboxylic acid, and hence show greater efficiency. 5 Although studies on reactive extraction of various carboxylic acid are abundant in literature, the same for complete extraction study (equilibrium, kinetics and modeling) for citric acid are limited, a handful of research work can be found in the literature including equilibrium [5][6][7][8][9][10][11][12] and kinetic studies [12][13] of citric acid extraction. Bizek et al 9 were the first to study the physical and reactive extraction equilibria of citric acid in different diluent and trialkyamine as an extractant.…”

“…They reported the acid•amine, acid•(amine) 2 complexes for extraction of citric acid that confirm the overloading of acid by trialkylamine. Aiming for a higher degree of extraction, Nikhade et al 10 used 30 % Alamine 366 in methylisobutylketone (MIBK) and found the distribution coefficient up to 67.147. They proposed the extraction accompanied by chemical reaction with a second order rate constant 0.013 m 3 kmol -1 s -1 .…”