Reactive extraction for separation of KCl and NH4Cl from aqueous solution using tributylamine

Extraction of carboxylic acids from dilute aqueous solution using traditional solvents such as ketones, alcohols, ethers, and ester is inefficient because the distribution ratio is rather low. Reactive extraction which exploits reversible chemical complexation is an effective separation process for extraction of carboxylic acids from aqueous streams such as fermentation broths and wastewaters. In the extraction process, selection of the solvent is an important aspect to be considered. Considering its solubility in water, cost and availability, tri-n-butyl phosphate (TBP) seems to be an attractive solvent for the extraction of lactic acid from aqueous solution. The purpose of this experiment is to study the equilibrium of the reactive extraction of lactic acid in aqueous solution with TBP in n-hexane. The parameters studied in this experiment were initial concentration of lactic acid in the aqueous phase, TBP concentration in n-hexane phase, and the extraction temperature. The experiments at ambient temperature were carried out using a separatory funnel, while the experiments at other than ambient temperature were carried out using erlenmeyer flask and water bath shaker to adjust the temperature. In this experiment, the initial concentration of lactic acid was varied from 0.1 to 0.5 gmol/dm3. The range of initial TBP concentrations in n-hexane was 0.1 to 1.0 gmol/dm3 and the extraction temperature range was 283 to 313 K. The experimental results showed that the higher the initial concentration of lactic acid in aqueous solution, the higher the distribution ratio for a fixed TBP concentration and extraction temperature. For a fixed initial concentration of lactic acid in aqueous solution and extraction temperature, the distribution ratio of lactic acid is increased by increasing TBP concentration. The overall equilibrium constants (Kpq) for the experiments using TBP concentration ranging from 0.1 to 1.0 gmol/dm3 at the extraction temperature of 293 K are calculated to be 0.0668 to 0.5144. Kpq for the experiments at the temperature ranging from 283 to 313 K at the initial concentration of lactic acid of 0.2 gmol/L are found to be 0.0122 to 0.8856. The Kpq as a function of temperature (T) in K can be expressed as ln Kpq = 10,596/T - 38.08 with sum of square of error of 0.14.

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Kinetics of Reactive Extraction of Pyruvic Acid Using Tributylamine Dissolved in n-Butyl Acetate

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2014-0117 ◽

2015 ◽

Vol 13 (1) ◽

pp. 63-69 ◽

Cited By ~ 8

Author(s):

Dharm Pal ◽

Amit Keshav

Keyword(s):

Aqueous Solution ◽

Rate Constant ◽

Pyruvic Acid ◽

Butyl Acetate ◽

Volume Ratio ◽

Kinetic Studies ◽

Extraction Process ◽

Reactive Extraction ◽

Kinetic Measurements ◽

Kinetics Of

Abstract Studies have been made on the kinetics accompanied with mass transfer for the pyruvic acid/tributylamine (TBA)/n-butyl acetate system to investigate the effectiveness of reactive extraction for the separation of pyruvic acid from the aqueous solution. In the present work, kinetic studies, needed for the design of a recovery unit, were carried out using aqueous solution of pyruvic acid. TBA (conc. range 0.420–2.099 kmol/m3) dissolved in n-butyl acetate (conc. range 50–90%) was used as an extractant. The effect of reactant concentration, the effect of stirring speed and the effect of phase volume ratio on the extraction process were investigated. The kinetic parameters such as reaction order and rate constant were calculated. Kinetic measurements showed that the reaction is of second order occurring in the diffusion film and was found to be independent of hydrodynamic conditions. Rate constant was evaluated to be $0.419\,{{\rm{m}}^3}{\rm{mo}}{{\rm{l}}^{- 1}}{{\rm{S}}^{- 1}}$ .

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