Separation of Succinic Acid from Aqueous Solution by Macroporous

Article pubs.acs.org/jced

Separation of Succinic Acid from Aqueous Solution by Macroporous Resin Adsorption Zhu Sheng,* Bo Tingting, Chen Xuanying, Wang Xiangxiang, and Long Mengdi College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China ABSTRACT: Attempts were made to recover succinic acid from aqueous solution by macroporous resin adsorption. The adsorption properties of succinic acid on seven different resins (HPD-300, HPD-400, HPD-450, HPD500, HPD-826, AB-8, and NKA-9) were compared systematically. According to the adsorption capacity, NKA-9 was chosen as the most suitable resin for succinic acid purification. The influences of solution pH, initial succinic acid concentration, and temperature were studied by the static adsorption method. The maximum adsorption capacity for succinic acid on NKA-9 was 155.9 mg· g−1 and obtained at pH 2.0, initial concentration 50 mg·mL−1 and 10 °C. Langmuir and Freundlich isotherms were used to describe the interactions between solutes and resins, and the equilibrium experimental data were well fitted to the two isotherms. The kinetic data were modeled using pseudo-firstorder, pseudo-second-order, and intraparticle diffusion equations. The experimental data were well described by the pseudo-second-order kinetic model.

1. INTRODUCTION Succinic acid, a dicarboxylic acid having the molecular formula of C4H6O4, is the important feedstock for several industrial products including tetrahydrofuran, adipic acid, 1,4-butanediol, aliphatic esters, and biodegradable plastics.1−4 Traditionally, succinic acid for industrial use is mainly produced from crude oil by catalytic hydrogenation of maleic anhydride to succinic anhydride and subsequent hydration or by direct catalytic hydrogenation of maleic acid. Facing the shortage of crude oil supply and sharply rising oil price as well as the increasing environmental pollution, the production of fermentationderived succinic acid (biosuccinic acid) from a renewable resource has potential as green technology because CO2 is consumed during the fermentation process.5−8 Succinic acid has been listed in the US Department Energy’s top 12 platform chemicals that could be produced from carbohydrates and has drawn worldwide concerns.9,10 Compared with the petrochemical route, biological succinic acid production is still not economically competitive mainly because of the difficulties in the downstream separation process. Succinic acid is hydrophilic and has a high boiling point. The product concentration in fermentation broth is usually not very high, about 5−15% in glucose-based medium. It is generally recognized that about 50−70% of the total costs for succinic acid production is generated by downstream processing.11 However, the research on downstream processing is much less than that on strain selection and fermentation process optimization. Therefore, downstream processing has become an obstacle for large scale production of succinic acid by the fermentation method.12 Several unit operations for succinic acid recovery from fermentation media have been proposed, such as selective precipitation with ammonia or © XXXX American Chemical Society

calcium hydroxide, membrane separation with ultrafiltration, nanofiltration, or electrodialysis,13−16 adsorption with ionexchange resin or alumina,17−20 extraction with solvents or amines,21−23 direct crystallization,24,25 and esterification method.14,26 In recent years, macroporous resin adsorption is gaining wider acceptance for extraction and purification of various biobased chemicals and other small molecules. Some studies have reported that this method has the advantages of high separation selectivity and low energy consumption.27−31 The macroporous resin has been displacing the traditional activated carbon and alumina as adsorbents gradually for its applications in environmental protection, fine chemical engineering, food and pharmaceutical industry. Macroporous resin adsorption of a solute onto the porous surface is a process including the steps of external mass transfer through a thin film of liquid phase and internal mass transfer by pore diffusion, both of which may play important roles.32 Besides, the interaction between the carboxylic group of succinic acid and the functional groups of resin can be very complex. All these motivate our desire to better understand the mechanism of such kind of adsorption. To our knowledge, there is no report on separating succinic acid from aqueous solutions by using macroporous resins. In this study, the optimum resin and pH value were selected by investigating the adsorption properties of succinic acid on different macroporous resins. The experimental isotherm data were analyzed using the Langmuir and Freundlich equations. The free energy, enthalpy, and entropy of adsorption were Received: August 23, 2015 Accepted: January 19, 2016

A

DOI: 10.1021/acs.jced.5b00713 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 1. Physical Characteristics of Adsorbent Resins type

porality

HPD-300 HPD-400 HPD-450 HPD-500 HPD-826 AB-8 NKA-9

nonpolar weak-polar weak-polar polar strong-polar weak-polar polar

0.30 0.30 0.30 0.30 0.30 0.30 0.30

to to to to to to to

1.20 1.20 1.20 1.20 1.25 1.25 1.25

800 500 500 500 500 480 250

evaluated. The adsorption kinetics were also tested and fitted by pseudo-first-order, pseudo-second-order, and intraparticle diffusion models.

to to to to to to to

870 550 550 550 550 520 290

average pore diameter (nm) 5.0 to 5.5 7.5 to 8.0 9.0 to 11.0 5.5 to 7.5 9.0 to 10.0 13.0 to 14.0 15.5 to 16.5

solute/volume solution); VL is the volume of liquid phase; and W is the amount of adsorbent used (mass). The effect of pH on the adsorption capacities of succinic acid was carried out by mixing 1 g (wet weight) of hydrated selected resin with 100 mL sample solutions (the initial concentration of succinic acid was 30 mg·mL−1 each) in the pH range of 1.0− 6.0. The sample pH was adjusted to the desired value with HCl or NaOH. Then, the flasks were shaken for 24 h at 20 °C. 2.4. Adsorption Isotherms. Experiments of adsorption isotherm at selected pH value on preliminary selected resins were performed. Briefly, 100 mL of succinic acid solutions at different initial concentrations (10, 20, 30, 40, and 50 mg· mL−1) were mixed with 1 g (wet weight) of resin, and then the samples were shaken (220 rpm) for 24 h at temperatures of 283, 293, and 303 K. At equilibrium, samples were analyzed for succinic acid concentrations. Two standard theoretical models, Langmuir and Freundlich models, are used to describe the adsorption behavior between adsorbate and adsorbent. The Langmuir isotherm is the best known and the most frequently used isotherm for the adsorption of solutes from a solution. The Langmuir model assumes that the surface of the pores of the adsorbent is homogeneous and that the forces of interaction between adsorbed molecules are negligible. Therefore, it is restricted to a monomolecular layer adsorption.33 The Langmuir equation can be expressed by the following mathematical formula:

2. EXPERIMENTAL SECTION 2.1. Chemicals and Reagents. Succinic acid (mass fraction purity ≥99.5%) was purchased from Shanghai Junhui Chemical Co., Ltd., China. HPLC grade (NH4)2HPO4 (mass fraction purity ≥99.5%) and methanol (mass fraction purity ≥99.9%) was obtained from Tianjin Kermel Chemical Reagent Co., Ltd., China and Tedia Co., Inc., USA, respectively. All the other chemicals used were AR grade and obtained at domestic market. Macroporous resins HPD-300, HPD-400, HPD-450, HPD500, HPD-826, AB-8, and NKA-9 were purchased from Cangzhou Bon Adsorber Technology Co. Ltd., China. All resins are made of styrene−divinylbenzene. The structural parameters of these resins are summarized in Table 1. The resins were soaked in 95% ethanol, shaken for 24 h, and then washed with acetone, ethanol, and distilled water, alternately. Finally, they were dried at 313 K and kept in desiccators for use. 2.2. Analytical Method. According to the recommendation of China National Standard, the concentrations of succinic acid were analyzed by high performance liquid chromatography (HPLC, 1260 series, Agilent, USA) equipped with an Wondasil C18 reverse phase column (5 μm, 250 mm × 4.6 mm I. D., Shimadzu Corporation, Japan) at a wavelength of 210 nm. The oven temperature was maintained at 303 K. The mobile phase was 0.01 M (NH4)2HPO4 adjusted to pH 2.70 by 1 M H3PO4. The flow rate was set to be 1.0 mL·min−1. Quantification of the succinic acid concentration in solution was achieved using calibration curves of peak area against injected concentration of the various succinic acid standards. 2.3. Resin Selection. The adsorption tests were performed as follows: 1 g (wet weight) of samples of hydrated test resins were put into flasks with a lid; 100 mL of sample solutions were added (the initial concentration of succinic acid was 30 mg· mL−1 each). The flasks were then shaken (220 rpm) for 24 h at 20 °C. After adsorption equilibrium was reached, the adsorbent was removed from the solution by filtration before determining the equilibrium concentration of succinic acid in the soluble phase. The adsorbed amounts of succinic acid q were calculated from (C − Ce)VL qe = 0 W

surface area (m2·g−1)

particle diameter (mm)

qe =

qmKLCe 1 + KLCe

(2)

where qe (mg·g−1 resin) and Ce (mg·mL−1) are the same as those in eq 1; KL (mL·mg−1) is the Langmuir constant; qm (mg· g−1 resin) is the maximum adsorption capacity. The Freundlich model is an empirical equation, used in the case where adsorption behavior cannot be properly fit by isotherms with a theoretical basis. It is derived by assuming a heterogeneous surface with a nonuniform distribution of the heat of adsorption over the surface. This model can be used to describe the adsorption behavior of a monomolecular layer as well as that of a multimolecular layer.34 The Freundlich equation can be expressed by the following mathematical formula: qe = KFCe1/ n

(3)

where KF is the Freundlich constant which is an indicator of adsorption capacity, and 1/n is an empirical constant related to the magnitude of the adsorption driving force. Both of them are temperature-dependent constants. Favorable adsorption corresponds to values of n less than 1, while a value of n greater than 1 indicates unfavorable adsorption. 2.5. Thermodynamic Studies. To explain the effect of temperature on the adsorption thermodynamic parameters,

(1)

where qe is the equilibrium solid phase concentration (mass solute/mass adsorbent); C0 is the initial liquid phase concentration (mass solute/volume solution); Ce is the equilibrium solute concentration in the aqueous phase (mass B



Article

Table 2. Experimental Adsorption Capacity Data of Succinic Acid on Different Resinsa qe (mg·g−1) a

HPD-300

HPD-400

HPD-450

HPD-500

HPD-826

AB-8

NKA-9

65.52 ± 0.98

65.04 ± 0.98

70.56 ± 1.06

76.08 ± 1.14

56.88 ± 0.85

76.20 ± 1.14

79.20 ± 1.19

Standard uncertainty u(T) = 0.2 K, and the combined standard uncertainties of qe are given in the table.

t 1 1 = t+ qt qe k 2qe2

standard Gibbs free energy (ΔG), standard enthalpy (ΔH), and standard entropy (ΔS) were determined. The adsorption process of succinic acid can be summarized by the following reversible process which represents a heterogeneous equilibrium. The thermodynamic equilibrium constant (K0) of the adsorption reaction is defined as K0 =

as νC = s s ae νeCe

The intraparticle diffusion model: qt = kpt 0.5 + L

(4)

Cs → 0

Cs a = s = K0 Ce ae

(10)

where qe and qt were the amounts of succinic acid adsorbed on the resin at equilibrium and at time t, respectively, k1 is the pseudo-first-order rate constant, k2 is the pseudo-second-order rate constant, kp is the intraparticle diffusion rate constant, and L represents the boundary layer diffusion effects (external film resistance).

where as is the activity of the adsorbed solute, ae is the activity of the solute in the equilibrium solution, Cs is the surface concentration of adsorbate in mmoles per gram of adsorbent, and Ce is the concentration of succinic acid in equilibrium suspension in mmol·ml−1, νs is the activity coefficient of the adsorbed solute, and νe is the activity coefficient of the solute in the equilibrium solution. As the concentration of the solute in the solution approaches zero, the activity coefficient v approaches unity. Equation 4 may then be written as lim

(9)

3. RESULTS AND DISCUSSION 3.1. Screening of resins. The adsorption capacity of succinic acid on seven macroporous resins at 20 °C are summarized in Table 2 and Figure 1. Among the seven

(5)

values of K0 can be determined by plotting ln(Cs/Ce) versus Ce and extrapolating Ce to zero.35 The free energy change (ΔG) is determined by the following relationship: ΔG = −RT ln K 0

(6) −1

−1

where R is the universal gas constant, 8.314 J·mol ·K , and T is the absolute temperature. The Gibbs free energy indicates the degree of spontaneity of the adsorption process, and the higher negative value reflects a more energetically favorable adsorption. The enthalpy change (ΔH) and the entropy change (ΔS) as a function of temperature are expressed by eq 7. ΔH and ΔS are obtained from the slope and the intercept of the plot of ln K0 against 1/T. ln K 0 = −

ΔH ΔS + RT R

Figure 1. Adsorption capacities of succinic acid on different resins.

adsorbents tested, NKA-9 had the largest adsorption capacity for succinic acid, reaching 79.20 mg·g−1 wet resin, accounting for a high degree of compatibility between adsorbent and succinic acid. It is known that succinic acid has two carboxyl groups, and is a polar compound. According to the principle of ‘“like dissolve like”’ for the resin adsorption selectivity, a polar compound usually has a higher absorptivity in polar resins, and those resins of too strong (HPD-826) or weak (HPD-300, HPD-400, HPD-450, and AB-8) polar may not suitable for the adsorptive separation and purification of succinic acid. In addition, although HPD-500 and NKA-9 are both polar resins as shown in Table 1, NKA-9 exhibited the larger adsorption capacity toward succinic acid, which implies that the pore size rather than the BET surface area is the predominant factor influencing the adsorption of succinic acid from aqueous solution. Since two or more succinic acid molecules can be connected together by intermolecular hydrogen bonding, which increases the molecular size of succinic acid, the average pore diameter of HPD-500 might be too small (5.5 to 7.5 nm) for

(7)

2.6. Adsorption Kinetics. The adsorption kinetics were studied at selected pH value on preliminary selected resins. The test for adsorption kinetics on the selected resins was conducted by adding 100 mL of succinic acid solutions (the initial concentration of succinic acid was 30 mg·mL−1) with 1 g (wet weight) of resin and then shaking (220 rpm) for 8 h at temperatures of 10, 20, and 30 °C. The concentrations of succinic acid in the adsorption solution were monitored at different time intervals until equilibrium. Three kinetic model equations including the pseudo-firstorder,36 pseudo-second-order,37 and intraparticle diffusion models38 were used to analyze the adsorption data. The pseudo-first-order model: ln(qe − qt ) = ln qe − k1t

(8)

The pseudo-second-order model: C



Article

The effects of pH on the adsorption capacity of succinic acid on the NKA-9 resin are listed in Table 3 and depicted in Figure 3. It can be observed that the highest adsorption capacity

adsorption. The relatively smaller pore size of HPD-500 might result in a more difficult diffusion of succinic acid molecules in the pores of the resins, inducing a relatively smaller capacity. In view of these results, the polar resin NKA-9 was selected to perform the subsequent investigation. 3.2. Effect of solution pH. One of the most important parameters influencing the adsorption capacity is the initial pH of adsorption solution.28 Succinic acid is a dicarboxylic acid, and the following dissociation equilibrium exists in aqueous solution: H 2SA ⇌ HSA− + H+,

HSA‐ ⇌ SA2 − + H+, Ka1 =

[HSA−][H+] , [H 2SA]

pKa1 = 4.21

(11)

pKa2 = 5.64 Ka2 =

log Ka1 = log[H+] + log

(12)

[SA2 −][H+] [HSA−]

(13)

−

[HSA ] , [H 2SA]

Figure 3. Effect of solution pH on the adsorption capacity of succinic acid onto NKA-9 resin.

[SA2 −] log Ka2 = log[H ] + log [HSA−] +

(14)

(82.20 mg·g−1) appeared at a pH of 2, and then decreased rapidly with the increase of the solution pH in the range of 2− 6. When the solution pH reaches to 6, the adsorption capacity has the minimum value of 7.44 mg·g−1. The similar variation tendency of the distribution coefficient of H2SA and the adsorption capacity of succinic acid with solution pH shows that the NKA-9 resin preferred to adsorb the molecule form rather than the ionic form. It can also be deduced that the adsorption mechanism maybe due to the van der Waals force and the hydrogen bonding interaction between undissociated succinic acid and cyano groups on the resin. The adsorption capacity at the pH of 1.0 is slightly smaller than that of 2.0. A possible explanation is that the excessive hydronium ion in the solution at pH 1.0 might be adsorbed on the resin as well through the hydrogen bond and occupied the vacant adsorption sites, which would slightly reduce the succinic acid adsorption. Similar results have been reported for the adsorption of D-lactic acid on macroporous resin.39 Nevertheless, the reduction of the adsorption capacity is insignificant. Therefore, the pH value of the solution was adjusted to 2.0 for all later experiments. 3.3. Adsorption Isotherms. The adsorption isotherms were studied in a temperature range of 10−30 °C. The results (Table 4 and Figure 4) indicated that the adsorption capacity of NKA-9 resin increased with the increment of succinic acid concentration. From Table 4 and Figure 4, it also shows that the succinic acid adsorption capacity decreased with increasing temperature for a certain initial concentration within the ranges of temperatures investigated. A possible explanation is that the adsorption of succinic acid onto macroporous resin is an exothermic process, and the increase of temperature is not in favor of adsorption. Moreover, the solubility of succinic acid in water increases with increasing temperature as shown in Table 5, which would also decrease the adsorption capacity of succinic

−

log

[HSA ] = pH − pKa1 , [H 2SA]

log

[SA2 −] = 2pH − pKa1 − pKa2 [H 2SA]

(15)

Thus, the distribution of various succinic acid species in aqueous solution at different pH values can be calculated and plotted in Figure 2. The existence form of succinic acid changes

Figure 2. Dissociation curves of succinic acid at different pH values.

with the pH value in solution: mostly in nonionized or molecule form (H2SA) at low pH (pH < 2), whereas mostly in bisuccinate (HSA−) and succinate (SA2−) ion form at high pH (pH > 6).

Table 3. Experimental Adsorption Capacity Data of Succinic Acid onto NKA-9 at Different pH Valuesa pH qe (mg·g−1) a

1.00 78.24 ± 1.17

2.00 82.20 ± 1.23

3.00 66.12 ± 0.99

4.00 35.28 ± 0.53

5.00 13.56 ± 0.20

6.00 7.44 ± 0.11

Standard uncertainty u(T) = 0.2 K, and the combined standard uncertainties of qe are given in the table. D



Article

which means that absorbent has a higher affinity for succinic acid than the liquid phase and succinic acid can be easily captured by the resin. The correlation coefficients show that the experimental points fitted well to both the Langmuir and Freundlich models. This implies that although the NKA-9 resin has heterogeneous surfaces, it has little effect on the adsorption of succinic acid. The adsorption state of succinic acid onto NKA-9 resin has the characteristics of both monolayer and multilayer adsorption. 3.4. Thermodynamic Studies. The Gibbs free energy (ΔG) of adsorption is calculated according to eq 6. As shown in Table 7, the values of ΔG are negative and within the range of −20 to 0 kJ·mol−1 at the temperatures of 10 and 20 °C, indicating that spontaneous physical adsorption occurred. However, when the temperature reached 30 °C, the ΔG value turned positive. The adsorption of succinic acid on NKA9 resin became a nonspontaneous process, and desorption was more favorable. Hot water might be used as eluent for desorption of succinic acid at high temperatures. The tendency of free energy varying with temperature is consistent with the experimental results above. Table 7 also contains estimates of the enthalpy (ΔH) and entropy (ΔS) obtained using the Van’t Hoff relation given by eq 7. The enthalpy is negative and its absolute value is less than 40 kJ·mol−1, which suggests that the adsorption of succinic acid to NKA-9 is an exothermic physisorption process. The negative value of entropy shows the decreased disorder degree of the adsorption system. This is because the range of succinic acid molecules movement is restricted by the adsorbent solid surface after the adsorption of succinic acid on NKA-9. 3.5. Adsorption Kinetics. Kinetic studies were performed in a temperature range of 10−30 °C at solution pH 2.0, and the results are given in Table 8. Figure 5 is a plot of the dimensionless bulk liquid concentration (Ct/C0) versus contact time (t). From Figure 5, it can be observed that the bulk liquid concentration of succinic acid decreased with time rapidly at the beginning 50 min and reached equilibrium after about 120 min. The besting fitting curves calculated by the pseudo-first-order and the pseudo-second-order models are presented in Figure 6. The corresponding mass transfer parameters are given in Table 9. As seen in Table 9, the correlation coefficients (R2) of the pseudo-second-order model are greater than that of the pseudo-first-order model. Besides, the qe (cal) values calculated from the pseudo-second-order model are closer to the experimental data qe (exp) than that calculated from the pseudo-first-order model. Therefore, it can be concluded that the succinic acid adsorption kinetics on NKA-9 resin are best fitted by the pseudo-second-order model.29,40 The mass transfer coefficients kn (either k1 or k2) increase slightly with the increase of temperature. In fact, an increase in temperature will increase the molecular motion and reduce the viscosity of liquid, allowing for greater mixing between the succinic acid molecules, solvent, and adsorbent. Moreover, increased molecular motion and reduced viscosity decrease the thickness of boundary layer, thus resulting in the increase of the mass transfer rate of succinic acid.

Table 4. Experimental Adsorption Equilibrium Data of Succinic Acid onto NKA-9 at Different Temperaturesa T (°C)

C0 (mg·mL−1)

Ce (mg·mL−1)

qe (mg·g−1)

10 10 10 10 10 20 20 20 20 20 30 30 30 30 30

10.91 20.31 29.88 39.25 48.91 10.76 20.24 29.30 38.91 48.42 10.74 19.98 29.57 38.96 48.07

10.46 19.48 28.74 37.91 47.36 10.41 19.62 28.51 37.89 47.25 10.50 19.58 28.98 38.25 47.27

45.60 ± 1.82 82.92 ± 1.74 113.76 ± 1.71 134.64 ± 1.62 155.88 ± 1.56 34.20 ± 1.37 61.80 ± 1.30 78.96 ± 1.18 102.00 ± 1.22 116.76 ± 1.17 24.00 ± 0.96 40.56 ± 0.85 58.32 ± 0.87 71.16 ± 0.85 79.92 ± 0.80

Standard uncertainties u are u(T) = 0.2 K, u(C) = 0.20 mg·mL−1, and the combined standard uncertainties of qe are given in the table. a

Figure 4. Adsorption equilibrium data fitted by Langmuir model and Freundlich model for the adsorption of succinic acid onto NKA-9 resin at different temperatures.

acid on NKA-9 resin. When the initial concentration of succinic acid and temperature of adsorption were 48.91 mg·mL−1 and 10 °C, respectively, the adsorption capacity of NKA-9 resin reached 155.88 mg succinic acid per gram resin. The Langmuir and Freundlich isotherms were used to fit the experimental data of succinic acid equilibrium adsorption on macroporous adsorbent NKA-9. The regression equations of Langmuir and Freundlich isotherms together with the model parameters and correlation coefficients at different temperatures are summarized in Table 6. Since the qm values (obtained from the Langmuir isotherm) and the KF values (obtained from the Freundlich isotherm) decreased with the increment of temperature, raising temperature is not preferred with regards to equilibrium adsorption capacity. For the Freundlich model, n values are higher than 1, indicating a favorable adsorption,

Table 5. Solubility of Succinic Acid in Water at Different Temperatures T (°C) solubility (W/W%)

0 2.80

10 4.51

20 6.80

25 8.06

30 10.58 E

40 16.21

50 24.42

60 35.83

70 51.07

80 70.70



Article

Table 6. Parameters Fittings with Langmuir and Freundlich Models at Varying Temperatures model parameters isotherm model

T (°C)

regression equation

R2

qm (mg·g−1 resin)

KL

10

1 1 = 0.2091 × + 0.0017 qe Ce

0.9978

588.2

0.0081

20

1 1 = 0.2756 × + 0.0026 qe Ce

0.9985

384.6

0.0094

30

1 1 = 0.3982 × + 0.0038 qe Ce

0.9991

263.2

0.0095

Langmuir

model parameters isotherm model

2

T (°C)

regression equation

R

KF

n

10

ln qe = 1.9511 + 0.8145 × ln Ce

0.9911

7.036

1.228

20

ln qe = 1.6575 + 0.8120 × ln Ce

0.9954

5.246

1.232

30

ln qe = 1.2739 + 0.8166 × ln Ce

0.9957

3.575

1.225

Freundlich

Table 7. Estimation of Thermodynamic Parameters for the Adsorption of Succinic Acid to NKA-9 T (°C)

K0

ΔG (kJ·mol−1)

ΔH (kJ·mol−1)

ΔS (J·mol−1·K−1)

10 20 30

1.5836 1.2767 0.9027

−1.0822 −0.5954 0.2580

−19.9744

−66.56

Table 8. Experimental Adsorption Kinetic Data of Succinic Acid onto NKA-9 at Different Temperaturesa T (°C)

C0 (mg·mL−1)

t (min)

Ct (mg·mL−1)

10 10 10 10 10 10 10 10 10 20 20 20 20 20 20 20 20 20 30 30 30 30 30 30 30 30 30

29.34 29.34 29.34 29.34 29.34 29.34 29.34 29.34 29.34 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 28.77 28.77 28.77 28.77 28.77 28.77 28.77 28.77 28.77

15 30 45 75 105 135 195 255 375 15 30 45 75 105 135 195 255 375 15 30 45 75 105 135 195 255 375

28.95 28.62 28.45 28.30 28.19 28.17 28.16 28.15 28.14 30.27 30.13 30.03 29.93 29.89 29.87 29.86 29.85 29.85 28.49 28.35 28.27 28.22 28.20 28.18 28.18 28.17 28.17

qt (mg·g−1) 39.24 72.12 89.52 104.52 115.20 117.72 118.68 119.40 119.88 34.44 49.32 59.04 69.36 72.48 75.00 75.84 76.68 77.16 28.20 41.88 50.04 54.48 57.24 58.32 59.16 59.64 59.88

± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

0.59 1.08 1.34 1.57 1.73 1.77 1.78 1.79 1.80 0.52 0.74 0.89 1.04 1.09 1.13 1.14 1.15 1.16 0.42 0.63 0.75 0.82 0.86 0.87 0.89 0.89 0.90

Figure 5. Adsorption kinetic curves of succinic acid on NKA-9 resin at different temperatures.

determine the rate-limiting step of the adsorption process. The plots obtained for qt versus t0.5 are shown in Figure 7a and the values of kp, L, and R2 are listed in Table 10. If the regression of qt versus t0.5 was linear and passed through the origin, then the adsorption process was controlled by intraparticle diffusion only. The relatively low correlation coefficients (0.65 < R2 < 0.71) and the positive values L for the adsorption of succinic acid on NKA-9 indicate that the intraparticle diffusion is not the only rate-controlling step and the external liquid film diffusion controls the adsorption to some degree. Although the intraparticle diffusion kinetic model cannot represent the whole adsorption processes, it is possible to distinguish three linear segments presenting three different kinetic stages from the plots of qt against t0.5 (Figure 7b). The values of kpi were determined from the slopes of the respective linear plots and are also presented in Table 10. As seen from Table 10, it can be found that the adsorption rates follow the order of the first stage (kp1) > second stage (kp2) > third stage (kp3). This phenomenon implies that the intraparticle diffusion is a three-serial cascade process.41 The first linear stage is most likely due to the adsorption occurring on the outside surface of adsorbents, and the diffusion resistance is small at this stage, leading to a high rate constant (kp1). The second stage corresponds to the diffusion of solute through the pores of

Standard uncertainties u are u(T) = 0.2 K, u(C) = 0.20 mg·mL−1, and the combined standard uncertainties of qe are given in the table. a

The intraparticle diffusion model given by eq 10 based on the theory proposed by Weber and Morris was utilized to F



Article

Figure 6. Adsorption kinetic data fitted by pseudo-first-order (a) and pseudo-second-order (b) model.

Table 9. Values of Kinetic Parameters for Pseudo-First-Order Equation and Pseudo-Second-Order Equation pseudo-first-order

pseudo-second-order

T (°C)

qe (exp) (mg·g−1)

R2

k1 (min−1)

qe (cal) (mg·g−1)

R2

k2 (mg·g−1·min−1)

qe (cal) (mg·g−1)

10 20 30

119.9 77.2 59.9

0.9145 0.9678 0.9748

0.0180 0.0183 0.0194

65.3 40.2 27.7

0.9965 0.9992 0.9993

3.82 × 10−4 7.78 × 10−4 1.28 × 10−3

128.2 81.3 62.5

Figure 7. Intraparticle diffusion kinetic plot (a) and plot in fragmented form (b).

Table 10. Values of Kinetic Parameters for Intraparticle Diffusion Equation at Different Temperatures first stage

second stage

third stage

T (°C)

kp (mg·g−1·min−0.5)

L (mg·g−1)

R2

kp1 (mg·g−1·min−0.5)

R2


R2


R2

10 20 30

4.497 2.464 1.695

51.675 39.232 34.032

0.6733 0.7071 0.6529

17.870 8.706 7.744

0.9900 0.9980 0.9952

4.520 1.908 1.309

0.9121 0.9996 0.9583

0.2136 0.2335 0.1267

0.9326 0.9105 0.8902

intraparticle diffusion model and k2 from pseudo-secondorder model with temperature confirm that the intraparticle diffusion was not the only rate-limiting step in the adsorption of succinic acid on NKA-9 resin.

adsorbents. The rate constant of kp2 became smaller, demonstrating that the diffusion resistance in this period increased. The last stage of the curves may be considered as the final adsorption and equilibrium on the inner surface of adsorbents. The smallest rate constant of kp3 indicates that the inner surface diffusion is the main resistance of the whole process. Furthermore, Table 10 shows that the intraparticle diffusion rate constants of first stage (kp1) and second stage (kp2) decrease with the increase of temperature. This is probably because the increase of temperature will enhance the intermolecular collisions of succinic acid and the collisions between succinic acid molecules and adsorbent surface within the pores of NKA-9, leading to a rise in intraparticle mass transfer resistance. The different tendencies of kpi from

4. CONCLUSIONS In the current study, the separation characteristics of seven kinds of styrene−divinylbenzene macroporous resins were systematically investigated by means of static adsorption experiments. NKA-9 exhibited higher adsorption capacity of succinic acid from aqueous solution than the other adsorbents, which resulted from suitable polarity and pore size. The best adsorption pH of succinic acid on NKA-9 was found to be 2.0. Both Langmuir and Freundlich equations fitted well the G



Article

an effective purification step for fermentation-derived succinic acid. J. Membr. Sci. 2014, 459, 132−142. (15) Wang, C. X.; Li, Q.; Tang, H. Clarification of succinic acid fermentation broth by ultrafiltration in succinic acid bio−refinery. J. Chem. Technol. Biotechnol. 2013, 88, 444−448. (16) Fu, L. L.; Gao, X. L.; Yang, Y.; Fan, A. Y.; Hao, H. W.; Gao, C. J. Preparation of succinic acid using bipolar membrane electrodialysis. Sep. Purif. Technol. 2014, 127, 212−218. (17) Schowe, N.; Bretz, K.; Hennig, T.; Schluter, S.; Deerberg, G. Succinic Acid Removal and Recovery from Aqueous Solution Using Hydrotalcite Granules: Experiments and Modeling. Ind. Eng. Chem. Res. 2015, 54, 1123−1130. (18) Asci, Y. S.; Inci, I. Extraction Equilibria of Succinic Acid from Aqueous Solutions by Amberlite LA-2 in Various Diluents. J. Chem. Eng. Data 2010, 55, 847−851. (19) Li, Q.; Xing, J. M.; Li, W. L.; Liu, Q. F.; Su, Z. G. Separation of Succinic Acid from Fermentation Broth Using Weak Alkaline Anion Exchange Adsorbents. Ind. Eng. Chem. Res. 2009, 48, 3595−3599. (20) Inci, I.; Bayazit, S. S.; Asci, Y. S. Separation of Succinic Acid from Aqueous Solution by Alumina Adsorption. J. Chem. Eng. Data 2011, 56, 4449−4453. (21) Kloetzer, L.; Cascaval, D.; Galaction, A. I. Influence of Solvent Polarity on Interfacial Mechanism and Efficiency of Succinic Acid Reactive Extraction with Tri-n-octylamine. Chem. Eng. Commun. 2013, 200, 701−717. (22) Inci, I.; Asci, Y. S.; Uslu, H. LSER modeling of extraction of succinic acid by tridodecylamine dissolved in 2-octanone and 1octanol. J. Ind. Eng. Chem. 2012, 18, 152−159. (23) Kurzrock, T.; Weuster-Botz, D. New reactive extraction systems for separation of bio-succinic acid. Bioprocess Biosyst. Eng. 2011, 34, 779−787. (24) Li, Q.; Wang, D.; Wu, Y.; Li, W. L.; Zhang, Y. J.; Xing, J. M.; Su, Z. G. One step recovery of succinic acid from fermentation broths by crystallization. Sep. Purif. Technol. 2010, 72, 294−300. (25) Lin, S. K. C.; Du, C. Y.; Blaga, A. C.; Camarut, M.; Webb, C.; Stevens, C. V.; Soetaert, W. Novel resin-based vacuum distillationcrystallisation method for recovery of succinic acid crystals from fermentation broths. Green Chem. 2010, 12, 666−671. (26) Delhomme, C.; Goh, S. L. M.; Kühn, F. E.; Weuster-Botz, D. Esterification of bio-based succinic acid in biphasic systems: Comparison of chemical and biological catalysts. J. Mol. Catal. B: Enzym. 2012, 80, 39−47. (27) Charpe, T. W.; Rathod, V. K. Separation of glycyrrhizic acid from licorice root extract using macroporous resin. Food Bioprod. Process. 2015, 93, 51−57. (28) Yang, J.; Zhang, L. Y.; Zhu, G. H.; Li, L. Separation and enrichment of major quinolizidine type alkaloids from Sophora alopecuroides using macroporous resins. J. Chromatogr. B: Anal. Technol. Biomed. Life Sci. 2014, 945, 17−22. (29) Li, Y.; Liu, J. B.; Cao, R. F.; Deng, S. G.; Lu, X. Y. Adsorption of Myricetrin, Puerarin, Naringin, Rutin, and Neohesperidin Dihydrochalcone Flavonoids on Macroporous Resins. J. Chem. Eng. Data 2013, 58, 2527−2537. (30) Du, H. B.; Wang, H.; Yu, J.; Liang, C. Y.; Ye, W. C.; Li, P. Enrichment and Purification of Total Flavonoid C-Glycosides from Abrus mollis Extracts with Macroporous Resins. Ind. Eng. Chem. Res. 2012, 51, 7349−7354. (31) Sheng, Z.; Jia-Wen, Z.; Kui, C. Effect of pH and ionic strength on competitive adsorption of erythromycin A and C onto macroporous resin Sepabead SP825 at different temperatures. Chem. Eng. Commun. 2011, 198, 1206−1217. (32) Grzegorczyk, D. S.; Carta, G. Adsorption of amino acids on porous polymeric adsorbents  I. Equilibrium. Chem. Eng. Sci. 1996, 51, 807−817. (33) Du, Z. Q.; Wang, K.; Tao, Y.; Chen, L. X.; Qiu, F. Purification of baicalin and wogonoside from Scutellaria baicalensis extracts by macroporous resin adsorption chromatography. J. Chromatogr. B: Anal. Technol. Biomed. Life Sci. 2012, 908, 143−149.

adsorption equilibrium data of succinic acid on NKA-9 at different temperatures. The free energy, enthalpy, and entropy of adsorption has also been evaluated, and the results show that adsorption of succinic acid on NKA-9 is an exothermic physisorption process. Through batch kinetic experiments, it is observed that succinic acid adsorption kinetics on NKA-9 resin can be satisfactorily described by the pseudo-second-order model.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail:[email protected]. Funding

This work was financially supported by the Young Teacher Cultivation Fund of Shanghai Municipal Education Commission (ZZsdl13022) and the Startup Fund of Shanghai University of Electric Power (K2013-004). Notes

The authors declare no competing financial interest.

■

REFERENCES

(1) Zeikus, J. G.; Jain, M. K.; Elankovan, P. Biotechnology of succinic acid production and markets for derived industrial products. Appl. Microbiol. Biotechnol. 1999, 51, 545−552. (2) Cukalovic, A.; Stevens, C. V. Feasibility of production methods for succinic acid derivatives: a marriage of renewable resources and chemical technology. Biofuels, Bioprod. Biorefin. 2008, 2, 505−529. (3) Bechthold, I.; Bretz, K.; Kabasci, S.; Kopitzky, R.; Springer, A. Succinic Acid: A New Platform Chemical for Biobased Polymers from Renewable Resources. Chem. Eng. Technol. 2008, 31, 647−654. (4) Delhomme, C.; Weuster-Botz, D.; Kühn, F. E. Succinic acid from renewable resources as a C4 building-block chemical  a review of the catalytic possibilities in aqueous media. Green Chem. 2009, 11, 13−26. (5) Song, H.; Sang, Y. L. Production of succinic acid by bacterial fermentation. Enzyme Microb. Technol. 2006, 39, 352−361. (6) Hermann, B. G.; Patel, M. Today’s and tomorrow’s bio-based bulk chemicals from white biotechnology: a techno-economic analysis. Appl. Biochem. Biotechnol. 2007, 136, 361−388. (7) Cok, B.; Tsiropoulos, I.; Roes, A. L.; Patel, M. K. Succinic acid production derived from carbohydrates: an energy and greenhouse gas assessment of a platform chemical toward a bio-based economy. Biofuels, Bioprod. Biorefin. 2014, 8, 16−29. (8) Shen, N.; Qin, Y.; Wang, Q.; Liao, S.; Zhu, J.; Zhu, Q.; Mi, H.; Adhikari, B.; Wei, Y.; Huang, R. Production of succinic acid from sugarcane molasses supplemented with a mixture of corn steep liquor powder and peanut meal as nitrogen sources by Actinobacillus succinogenes. Lett. Appl. Microbiol. 2015, 60, 544−551. (9) Werpy, T.; Petersen, G. Top Value Added Chem1cals from Biornass: Results of Screening for Potential Candidates from Sugars and Synthesis Gas. US Department of Energy. 2004, DOI: 10.2172/ 15008859. (10) de Jong, E.; Higson, A.; Walsh, P.; Wellisch, M. Bio-based Chemicals-Value Added Products from Biorefineries. Biofuels, Bioprod. Biorefin. 2012, 6, 606. (11) Cheng, K. K.; Zhao, X. B.; Zeng, J.; Wu, R. C.; Xu, Y. Z.; Liu, D. H.; Zhang, J. A. Downstream processing of biotechnological produced succinic acid. Appl. Microbiol. Biotechnol. 2012, 95, 841−850. (12) Kurzrock, T.; Weuster-Botz, D. Recovery of succinic acid from fermentation broth. Biotechnol. Lett. 2010, 32, 331−339. (13) Antczak, J.; Regiec, J.; Prochaska, K. Separation and Concentration of Succinic Adic from Multicomponent Aqueous Solutions by Nanofiltration Technique. Pol. J. Chem. Technol. 2014, 16, 1−4. (14) Lubsungneon, J.; Srisuno, S.; Rodtong, S.; Boontawan, A. Nanofiltration coupled with vapor permeation-assisted esterification as H



Article

(34) Wei, Z. F.; Zu, Y. G.; Fu, Y. J.; Wang, W.; Zhao, C. J.; Luo, M.; Efferth, T. Resin adsorption as a means to enrich rare stilbenes and coumarin from pigeon pea leaves extracts. Chem. Eng. J. 2011, 172, 864−871. (35) Khan, A. A.; Singh, R. P. Adsorption thermodynamics of carbofuran on Sn (IV) arsenosilicate in H+, Na+ and Ca2+ forms. Colloids Surf. 1987, 24, 33−42. (36) Lagergren, S. Zur theorie der sogenannten adsorption geloster stoffe. K. Sven. Vetenskapsakad. Handl. 1898, 24, 1−39. (37) Ho, Y. S.; McKay, G. Pseudo-second order model for sorption processes. Process Biochem. 1999, 34, 451−465. (38) Torrado, A.; Valiente, M. Kinetics characterization of ions release under dynamic and batch conditions. Strong acid and strong base type ion exchange resins. Solvent Extr. Ion Exch. 2008, 26, 240− 260. (39) Wu, J. L.; Hu, Y. A.; Zhou, J. W.; Qian, W. B.; Lin, X. Q.; Chen, Y.; Chen, X. C.; Xie, J. J.; Bai, J. X.; Ying, H. J. Separation of D-lactic acid from aqueous solutions based on the adsorption technology. Colloids Surf., A 2012, 407, 29−37. (40) Wang, Y. J.; Wu, Y. F.; Xue, F.; Wu, Z. X.; Xue, Y. P.; Zheng, Y. G.; Shen, Y. C. Isolation of brefeldin A from Eupenicillium brefeldianum broth using macroporous resin adsorption chromatography. J. Chromatogr. B: Anal. Technol. Biomed. Life Sci. 2012, 895, 146−153. (41) Tütem, E.; Apak, R.; Ü nal, Ç . F. Adsorptive removal of chlorophenols from water by bituminous shale. Water Res. 1998, 32, 2315−2324.

I


Separation of Succinic Acid from Aqueous Solution by Macroporous

Recommend Documents