Adsorption Study for the Separation of Isonicotinic Acid from Aqueous

Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX

pubs.acs.org/jced

Adsorption Study for the Separation of Isonicotinic Acid from Aqueous Solution Using Activated Carbon/Fe3O4 Composites Drishti Bhatia, Dipaloy Datta,* Abhishek Joshi, Sagar Gupta, and Yogesh Gote Department of Chemical Engineering, Malaviya National Institute of Technology (MNIT), Jaipur, Rajasthan 302017, India ABSTRACT: Activated carbon (AC) was modified by the coprecipitation method to induce magnetic properties for the removal of isonicotinic acid (iNA). Magnetization was done by using salts of Fe2+ and Fe3+ as precursors. The induced magnetism in magnetic activated carbon (MAC) was confirmed by Fourier transform infrared and field-emission scanning electron microscopy−electron diffraction spectroscopy analyses. Also, the stability of both AC and MAC was tested by TGA. Batch adsorption experiments were performed using both AC and MAC to see the effects of adsorption time (0−180 min), adsorbent amount (12−40 g/L for AC and 4− 80 g/L for MAC), initial iNA concentration (1.23−6.16 g/L), and temperature (298−333 K) on the removal efficiency. Steady state was reached at 120 min by using both adsorbents. Equilibrium data was best fitted by Langmuir and Temkin isotherms for AC and MAC, respectively. The maximum adsorption capacities were noted to be 0.406 g/g of AC and 0.071 g/g of MAC. Pseudo-second-order model fitted the kinetic data for both adsorbents. The magnetic property in MAC ensured easy separation of adsorbent using magnet after adsorption from the aqueous medium.

1. INTRODUCTION Activated carbon (AC) is a novel adsorbent to remove various compounds from water. Due to its large available surface area, high surface reactivity, and high pore volume, AC is preferred over most of the other available low cost adsorbents. Mohan and Pittman1 reviewed in their paper the adsorption capacity of various adsorbents such as iron oxide coated sand, char carbon, activated pisolite, etc. for the removal of arsenic from wastewater. AC can be prepared from wide range of easily available feed stocks such as bones, bagasse, coconut shells, corncobs, lignin, etc.2 Recently, introduction of magnetism in activated carbon has gained importance as it helps in overcoming the tedious separation of AC by centrifuge process.3 Numerous approaches of purification and separation are used by researchers, which include biological treatment,4 ion exchange for treatment of unwanted substances,5,6 membrane filtration,7 coagulation and flocculation,8 and photocatalytic degradation.9 Adsorption is preferred over all the methods because of its effectiveness, efficiency, and economy. Magnetic activated carbon (MAC) can be used as an adsorbent for the removal of harmful substances such as heavy metals, dyes, and organic compounds. Heavy metals such as cadmium, lead, arsenic, mercury, zinc, copper, etc. can be harmful, especially to human life if exposure is over recommended limits. Overexposure may lead to gastrointestinal disorders, diarrhea, tremor, hemoglobinuria, paralysis, vomiting, depression, and pneumonia. The discharge of dyes (which are hazardous substances) by textile industries pollutes the environment, leaving harmful effects. As an example, malachite green and triphenyl methane dyes are very hazardous and highly lethal to mammalian cells. Methylene blue dye on inhalation can cause difficulty in breathing or rapid breathing, while intake through mouth causes a burning sensation and may cause nausea, vomiting, diarrhea, and gastritis. © XXXX American Chemical Society

Accidental intake of heavy doses can lead to abdominal and chest pain, profuse sweating, mental confusion, severe headache, painful micturition, and methemoglobinemia.10 Textile dyes can also be mutagenic and carcinogenic.11 On the other hand, organic compounds (phenol, aniline, triphenol, cyanide, etc.) are harmful to humans as well as other living beings. In humans, they can cause irritation and harm to eyes, skin, and the respiratory tract. They can also cause a narcotic effect on the nervous system and damage internal organs such as the liver and kidneys. In addition, some compounds are especially harmful to specific organs or can cause diseases such as cancer.12 A brief summary of compounds being removed by MAC is shown in Table 1. Faulconer et al.13 used magnetic powdered activated carbon to remove Hg(II) to a final concentration of less than 0.2 μg/L. Ninety percent of the removal was done in the initial step itself, reaching pseudoequilibrium at 120 min. Fu et al.14 synthesized a novel adsorbent (AC/Fe3O4@SiO2−NH2) by co-condensation method to enhance the removal of Pb(II). Nethaji et al.15 used MAC from corn cob to separate Cr(VI). They concluded that adsorption of Cr(VI) was both by film diffusion and intraparticle diffusion, and the external mass transfer was the ratedetermining step. Zhang et al.16 studied performance of prepared magnetic CuFe2O4/activated carbon for Acid Orange II removal. This composite showed higher adsorption capacity with no considerable decrease in the microporosity and surface area due to the presence of copper ferrite. The same result was obtained by Ai et al.,17 who used AC/CoFe2O4 composite to remove malachite green dye from wastewater. Luo et al.18 used maghemite (γ-Fe2O3) nanoparticles to study adsorption and Received: October 8, 2017 Accepted: January 12, 2018

A

DOI: 10.1021/acs.jced.7b00881 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 1. Removal of Different Compounds Using Magnetic Activated Carbona compounds

concentration

kinetic model

1.23−6.16 g/L

maximum adsorption capacity (mg/g)

1

isonicotinic acid

2 3 4

Pb(II) chromium(VI) acid orange II

5 6

malachite green organic dyes

Langmuir for AC and Temkin for pseudo-second-order MAC 20−250 mg/L Langmuir pseudo-second-order 100−1000 mg/L Freundlich pseudo-second-order 500−1000 mg/L Langmuir for AC and Freundlich for composite 100 mg/L Langmuir pseudo-second-order 0.2−2 mmol/L Langmuir pseudo-second-order

7

aniline

50−300 mg/L

Freundlich

pseudo-second-order

8

methyl orange

100−700 mg/L

Langmuir

pseudo-second-order

182.2

9

trinitrophenol

23−228 mg/L

Sips for ASAC and MASAC, Langmuir for F 400 Langmuir

pseudo-first and -second-order pseudo-second-order

327.85

Langmuir for RACF and Langmuir−Freundlich for MACF Freundlich

pseudo-second-order

8.74

Langmuir

pseudo-second-order

62.94

Langmuir

pseudo-second-order

108.69

pseudo-second-order

321 67.82

10 methyl orange

500 mg/L

11 arsenic

2 mg/L

12 arsenate (AsO43−)

10−40 mg/L

13 Congo red 10−70 mg/L (C32H22N6Na2O6S2) 14 basic dye (Alizarin red S) 50−150 mg/L 15 methylene blue 16 cyanide a

equilibrium isotherm model

Langmuir 500−1000 mg/L Langmuir and Redlich−Peterson

pseudo-second-order

393.7 104.2 57.37 654 89.29 2.41 90.91

384.62

204.2

optimum condition

ref

T = 323 K, t* = 2 h, w# = 4 g/L pH 5.2, T = 333 K, t* = 20 h pH 2, w# = 1 g/L pH 5.2, t* = 24 h, w# = 2 g/L

present study 14 15 16

pH 5, t* = 20 min, w# = 2 g/L pH 6.7,T = 298 K, t* = 180 min pH 6.5, T = 293 K, t* = 5 h, w# = 1 g/L pH 3, T = 303 K, t* = 30 min, w# = 0.3 g/L pH 2, t* = 48 h, w# = 3 g/L

17 18 19 20 21

T = 303 K, t* = 180 min, w# = 22 0.1 g/L pH 4, T = 300 K, t* = 24 h, w# 23 = 0.7 g/L pH 8,T = 313 K, t* = 6 h, w# = 0.2 g/L pH 4,T = 298 K, t* = 10 h, w# = 1.0 g/L pH 2, T = 298 K, t* = 4 h, w# = 0.02 g/L T = 298 K, t* = 5 h pH 7.5, T = 298 K, t* = 72 h, w# = 1.5 g/L

38 39 40 41 42

t* = equilibrium time, T = equilibrium temperature, w# = adsorbent dosage.

Figure 1. Magnetized activated carbon.

Figure 2. FTIR plot of activated carbon and magnetic activated carbon. Symbols: thin line, AC; bold line, MAC.

desorption of methyl orange and methylene blue. The adsorption on the surface of adsorbent was mainly driven by the Van der Wall’s force. Aniline separation using synthesized MAC was performed by Kakavandi et al.19 They found a better removal of aniline at near neutral pH (6) with maximum adsorption capacity of 90.91 mg/g. In another study by Jiang et al.,20 synthesized magnetic AC/NiFe2O4 was used for removing methyl orange. The adsorption efficiency reached to 93% in first 2 min and 99% in 30 min. The adsorbent could be reused six times for the separation of methyl orange. Mohan et al.21 prepared low cost MAC from almond shell to separate 2,4,6trinitrophenol. Do et al.22 conducted experiments for the adsorption of methyl orange from water. They proposed that Fe3O4 nanoparticles could be important in achieving high regeneration efficiency for MAC using hydrogen peroxide. Zhang et al.23 compared the adsorption characteristics of modified

Figure 3. TGA plot of activated carbon and magnetic activated carbon. Symbols: thin line, AC; bold line, MAC. B



Article

Figure 4. FE-SEM images of (a) AC and (b) MAC.

activated carbon fiber (ACF) with raw ACF for the removal of As(V). Modified ACF revealed better adsorption capacity (almost eight times) than that of raw ACF. From the kinetics of adsorption, they found that diffusion of As(V) in the pores was faster in modified ACF as compared to in raw ACF. Carboxylic acids are products of high commercial importance in various industries and hence need to be separated from their fermentation broths. Pyridine carboxylic acids (picolinic, nicotinic, and isonicotinic acids) are widely used in the fields of

medicine (pharmaceutical industry), foods, and petrochemicals. Picolinic acid can make chelates with metals such as Fe, Zn, Pb, Cr, and Mo inside the human body24 and are hence used as supplements for food and better metabolism for controlling type 2 diabetes.25 Isonicotinic acid plays an important role in the formation of the steroid hormones as well as DNA repair. Any insufficiency in the body can lead to the slower metabolism, causing decreased immunity to the cold. A serious deficiency in the nicotinic acid may result in pellagra. This acid also C



Article

Figure 5. EDS images of (a) AC and (b) MAC. D



Article

Figure 6. Kinetic data for the removal of isonicotinic acid (6.16 g/L) 100 N ⎛ |qexp − qcal| ⎞ ⎟ by activated carbon (20 g/L) at 298 K. % APE = N ∑i = 1 ⎜ q ⎝ exp ⎠ N = number of data points PFO (line, % APE = 0.570%); PSO (---, % APE = 1.184%); IPD (···, % APE = 14.369%); ■, experimental.

Figure 7. Kinetic data for the removal (6.16 g/L) by magnetic activated carbon 100 N ⎛ |qexp − qcal| ⎞ ⎟ N = number % APE = N ∑i = 1 ⎜ q ⎝ exp ⎠ (line, % APE = 17.258%); PSO (---, % APE = APE = 10.607%); ■, experimental.

Figure 8. Equilibrium isotherms for the removal of isonicotinic acid by 100 N ⎛ |qexp − qcal| ⎞ ⎟ N = AC (20 g/L) at T = 298 K. % APE = N ∑i = 1 ⎜ q ⎝ exp ⎠ number of data points; Langmuir (line, % APE = 1.878%); Freundlich (---, % APE = 2.673%); Temkin ···, % APE = 9.454%); ■, experimental.

Figure 9. Equilibrium isotherms for the removal of isonicotinic acid by magnetic activated carbon (20 g/L) at T = 298 K. 100 N ⎛ |qexp − qcal| ⎞ ⎟ N = number of data points; Langmuir %APE = N ∑i = 1 ⎜ q ⎝ exp ⎠ (line, % APE = 6.966%); Freundlich (---, % APE = 3.897%); Temkin (···, % APE = 2.769%); ■, experimental.

of isonicotinic acid (4 g/L) at 298 K. of data points PFO 13.612%); IPD (···, %

plays a vital role in the production of anti-tuberculosis (TB) drugs, serving as a key intermediate in the process. Pyridine carboxylic acid is mainly obtained by chemical synthesis at high temperature and pressure conditions. To obtain a good quality of products with desired chemical properties, a complicated process of chemical synthesis must be followed. Nowadays, a fermentation path is also being followed to produce pyridine carboxylic acids, but this process is not able to compete with the chemical synthesis method if a concentrated amount of acid is required. In this study, AC and MAC were used as adsorbents to remove iNA from aqueous solution. To determine the suitable condition for adsorption, various parameters such as time of contact, adsorbent concentration, iNA concentration, and temperature were varied to obtain experimental data. The experimental data were then fitted using various models as follows: equilibrium data were fitted using Langmuir, Freundlich, and Temkin isotherm

Table 2. Effect of Adsorption Dosage for the Removal of Isonicotinic Acid (6.16 g/L) at 298 K adsorbent dosage (g/25 mL) 0.3 0.5 0.6 1 0.1 0.5 1 2

adsorption capacity (g/g) AC 0.250 0.190 0.169 0.121 MAC 0.474 0.211 0.128 0.065

percentage removal (%) 45.69 58.05 61.80 74.16 28.84 64.42 77.90 85.20 E



Article

Table 3. Isotherm Parameters for Activated Carbon and Magnetic Activated Carbon Langmuir

1 qe

=

1 KLqmCe

+

1 48 qm

1

Freundlich ln qe = ln KF + n ln Ce 49

Temkin qe = qm ln(KT) + qm ln(Ce)50

parameter

AC value

MAC value

parameter

AC value

MAC value

parameter

AC value

MAC value

qm (g/g) KL (L/g) R2

0.406 0.264 0.999

0.175 6.542 0.982

KF [(g/g) (L/g)1/n] n R2

0.082 1.288 0.996

0.146 2.962 0.989

qm (g/g) KT (L/g) R2

0.071 3.777 0.969

0.037 4.080 0.993

models, and the kinetic data were fitted using pseudo-first-order (PFO), pseudo-second-order (PSO), and intraparticle diffusion models (IPD) to evaluate the best fit condition.

in an inert atmosphere. The FE-SEM + EDS images are obtained by Nova Nano FE-SEM 450 (PerkinElmer). 2.2.3. Adsorption Experiments. Batch equilibrium technique was used to perform adsorption experiments in a temperature controlled water shaker bath (Remi Lab, India). Kinetic study was done for both AC (20 g/L) and MAC (4 g/L) with 6.16 g/L initial concentration of isonicotinic acid solution up to 180 min of time. The effect of adsorbent dosage was investigated in the range of 12−40 g/L for , and 4− 80 g/L for MAC in 25 mL of aqueous solution of 6.16 g/L isonicotinic acid at 298 K. For isotherm study, the concentration range of isonicotinic acid was chosen as 1.23−6.16 g/L with dosage of 20 g/L AC and 4 g/L MAC for a total time of 120 min. To study the effect of temperature on adsorption, experiments were carried out at 298, 313, 323, and 333 K. The concentrations of isonicotinic acid solutions were determined by titration against 0.01 N NaOH. The equilibrium concentration of isonicotinic acid in the aqueous phase was also determined by using a UV spectrophotometer (Shimadzu, UV-1800, Japan) at 262 nm. It was observed that when titration was used, the deviation in the quantification of acid concentration in the aqueous phase is less than 1%. Also, in the titration, a very dilute solution of NaOH (0.01 N) was used to minimize the analytical error in determining the equilibrium aqueous phase concentration of isonicotinic acid. Therefore, titration was considered to measure the concentration of acid in the aqueous phase at equilibrium. The adsorption capacity (qe) in g/g of adsorbent was calculated by eq 2.

2. MATERIALS AND METHODS 2.1. Materials. Activated carbon (powdered, 300 mesh) was obtained from Central Drug House (P) Ltd., sodium hydroxide and iron(III) chloride (anhydrous) (purity = 96%) from Qualigens Fine Chemicals, iron(II) sulfate heptahydrate (purity = 98%) and nitric acid (69%) from Merck Specialties Pvt. Ltd., and isonicotinic (purity = 99%) from Spectrochem Pvt. Ltd., India. Ethanol (purity >99%) was procured from Merck, Germany and was used for washing of prepared MAC. 2.2. Method. 2.2.1. Preparation of MAC. The preparation of MAC was done using the previously reported method.26 It involved series of steps which could be broadly classified into washing/oxidation, impregnation of iron oxides on the surface, and then drying of MAC. Initially, 10 g of AC was taken and then was treated with 50 mL of HNO3 (20%) at 343 K for 6 h under constant stirring using a magnetic stirrer (Remi Lab, India, Model 2 MLH) maintained at 400 rpm. In the next step, the pH of the solution was brought back to neutral by washing with deionized water. The sample was then dried in a hot air oven (SONAR OPS-9096-250, Associated Scientific Technologies, India) at a temperature of 383 K. For the impregnation of iron oxides, a mixed solution of 0.01 M anhydrous iron(III) chloride (FeCl3) and 0.05 M iron(II) sulfate heptahydrate (FeSO4·7H2O) was prepared in a mole ratio of Fe2+:Fe3+ as 1:2. The mass ratio of the (Fe2+ + Fe3+):AC was kept at 4:1, and the solution was stirred for about 2 h. The reaction involved in the process is given below as eq 1. Fe 2 + + 2Fe3 + + 8OH− → Fe3O4 ↓ +4H 2O

qe =

(C0 − Ce)V m

(2)

where C0 (g/L) is the initial concentration of acid and Ce (g/L) is the equilibrium concentration of the acid. V (in L) is the volume of the solution, and m (g) is the amount of adsorbent. The removal efficiency was calculated by eq 3.

(1)

The precipitation of Fe3O4 occurs when the pH is maintained between 10 and 12.26,27 In this study, pH was maintained at 11. The sample was then aged for about 4 h at 343 K. After aging, the solution was allowed to cool. The magnetized AC was then separated by a magnet. The final treatment of the MAC was completed by washing it with deionized water and then treating it with ethanol. The prepared MAC was kept for drying at 353 K for 4 h in the hot air oven (SONAR OPS-9096-250, Associated Scientific Technologies, India). The magnetic property developed in the MAC was confirmed by using a magnet, as shown in Figure 1. 2.2.2. Characterization. Characterization of AC and MAC was done by using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and field-emission scanning electron microscopy−electron diffraction spectroscopy (FE-SEM + EDS). FTIR data were taken in a range of 4000−400 cm−1 by FT-IR Spectrum 2 (PerkinElmer, United States). Different peaks of percentage transmission were studied and analyzed. TGA study was done by STA 6000 (PerkinElmer) for analyzing the decrease in the weight percent in the temperature range of 30 to 1000 °C at a scanning speed of 10 °C/min

% removal =

(C0 − Ce) × 100 C0

(3)

3. RESULTS AND DISCUSSION 3.1. Characterization. Characterization of AC and MAC was done using FTIR, TGA, and FE-SEM + EDS techniques to confirm the embedding of magnetic properties in raw AC. 3.1.1. Fourier Transform Infrared Spectroscopy. The FTIR plots of AC and MAC showing percent transmission with respect to wavelength are given in Figure 2. The peak between 3500− 3200 cm−1 in the plot of MAC is indicative of the presence of more alcoholic groups in MAC as compared to AC. This addition might have taken place during the magnetization process. The appearance of absorption bands between 1300−1000 cm−1 is indicative of the presence of both hydroxyl and ether type groups in AC. The peaks at 1536.70 and 1571.37 cm−1 in AC and MAC, respectively, indicate the presence of C−O functional groups present in AC.28 Also, a peak at 1709.46 cm−1 F



Article

pertains to the presence of Fe−O stretching.30 Additional band at around 578 cm−1 in MAC depicts the presence of iron oxide in the sample.31 3.1.2. Thermogravimetric Analysis. TGA plots of AC and MAC are shown in Figure 3, showing a decrease of approximately 10 and 15 wt % for AC and MAC, respectively, at temperatures below 100 °C, which can be attributed to dehydration and elimination of oxygen containing functional groups from the surface.31 A continuous decrease in weight percentage with the rise in temperature was observed, which can be understood as burning of carbon particles. The tail at higher temperature shows some of the impurities present in the adsorbate. A sudden decrease, seen in the TGA plot for MAC between 650 and 700 °C, is the point where complete burning of the activated carbon has taken place. After the burning of carbon from the sample, Fe2O3 is the major compound remaining in the sample along with some impurities.32 A further decrease can again be seen in the tail, showing combustion of the leftover compounds. 3.1.3. Field Emission Scanning Electron Microscopy and Electron Dispersion X-ray Spectroscopy. The morphology of AC and MAC was analyzed by FE-SEM (Figures 4a for AC and b for MAC), and their elemental composition was determined with the help of EDS (Figures 5a for AC and 5b for MAC). Figure 4a shows that the surface is rough with pores, and sites are available for adsorption of iNA. Again, from Figure 4b, it can be observed that Fe3O4 particles agglomerate on the surface of AC.33 The EDS images confirm that there is a peak of iron in MAC, which shows the presence of 25.67 wt % iron on the surface of MAC. Furthermore, a decrease in weight % of carbon is also observed in MAC compared to that of AC.34 3.2. Effect of Contact Time. The dynamic behavior of the adsorption of isonicotinic acid molecules onto AC and MAC is shown in Figures 6 and 7, respectively. At initial times, a faster removal rate of adsorption of acid molecules from aqueous phase to solid phase was observed. This was due to the high availability number of vacant sites on the adsorbate, which becomes occupied by isonicotinic acid molecules with the passage of time. This is explained by the experimental plots. After sufficient contact time, equilibrium between adsorption and desorption was established, and no net mass transfer takes place. This was because of existence of repulsive force between the solute molecule present on the adsorbent and in the bulk aqueous phase. The removal efficiency of acid molecules was found to be 58.05% with 20 g/L of AC and 25.82% with 4 g/L of MAC with 6.16 g/L of acid after 120 min. Hence, it is observed that after 120 min, a steady state is established. 3.3. Effect of Adsorbent Amount. To observe the effect of adsorbent amount, the concentrations of AC were 12, 20, 24, and 40 g/L, and the concentrations of MAC were 4, 20, 40, and 80 g/L with 6.16 g/L isonicotinic acid, and the data are shown in Table 2. The effect of variation in AC and MAC dosage was seen in terms of adsorption capacity (qe) and percentage removal of isonicotinic acid. With MAC, it is observed that the percent removal increased from 28.84 to 85.20%, and the adsorption capacity decreased from 0.474 to 0.065 g/g with increase in the adsorbent dosage. With AC, the percent removal increased from 45.69 to 74.16%, and the adsorption capacity decreased from 0.250 to 0.121 g/g. 3.4. Effect of Initial Isonicotinic Acid Concentration. To observe the effect of initial isonicotinic acid concentration on the adsorption process, solutions having initial isonicotinic concentrations of 1.23, 2.46, 3.69, 4.92, and 6.16 g/L were prepared with 20 g/L of MAC and AC separately. The

Figure 10. Determination of the (a) Langmuir, (b) Freundlich, and (c) Temkin model parameters for the adsorption of isonicotinic acid on adsorbents (■, AC; ●, MAC; line, linear fit) with a concentration of 6.16 g/L at 298 K.

is assigned to stretching vibration of ketones, aldehydes, lactones, or carboxyl groups.29 The peak at 1348.41 cm−1 in MAC G



Article

Table 4. Kinetic Model Parameters for Activated Carbon and Magnetic Activated Carbon q ⎞ ⎛ PFO ln⎜1 − q t ⎟ = − k1t 43,44 ⎝ m⎠ parameter AC value MAC value

qm (g/g) k1 (min−1) R2

0.191 0.074 0.992

0.388 0.060 0.625

PSO

t qt

=

1 2 k 2qm

+

t 44,45 qm

IPD qt = kint0.5 + c46,47

parameter

AC value

MAC value

parameter

AC value

MAC value

qm (g/g) k2 (g/g/min) R2

0.192 4.128 0.999

0.394 0.279 0.960

kin c R2

0.013 0.046 0.718

0.030 0.056 0.902

equilibrium isotherms between isonicotinic acid concentration in the solid phase and aqueous phase were plotted as shown in Figures 8 and 9 for AC and MAC, respectively. The curve shows that the percent removal decreased from 66 to 55.20%, and the adsorption capacity increased from 0.040 to 0.176 g/g for AC. For MAC, the percent removal decreased from 94 to 61.6%, and the adsorption capacity increased from 0.057 to 0.167 g/g. This happened due to saturation of active sites on adsorbent with the solute molecules. 3.5. Equilibrium and Kinetic Adsorption Models. The equilibrium modeling of adsorption of isonicotinic acid molecules on the adsorbents, AC, and MAC was carried out by using Langmuir, Freundlich, and Temkin isotherm models. According to equations given in Table 3, a plot was made between 1 qe

versus

1 Ce

for fitting the data to the Langmuir isotherm. In the

Freundlich model, a straight line is plotted between lnqe versus lnCe. In the Temkin model, a straight line is plotted between qe versus lnCe. The plots are shown in Figure 10. From the plots, it can be deduced that for AC, the Langmuir isotherm demonstrated the best fit with R2 equal to 0.999. For MAC, the Temkin isotherm represented the best fit with R2 equal to 0.993. The adsorption of isonicotinic acid showed almost linear relationship between qe and Ce with AC. As the initial concentration of acid is low in the aqueous phase, the Langmuir isotherm best fitted the data for AC. In case of MAC, the nonlinear nature of the data represented the most favorable conditions for type I adsorption as even at low concentrations the surface of adsorbent may be loaded with high amounts of materials. Type I isotherm may be seen for very small pores or microporous adsorbents, and the adsorption occurs by filling of the micropores. The adsorbate uptake rate depends on the accessible micropore volume rather than total internal surface area. Figure 9 for MAC depicts a monolayer type of adsorption which can also be easily explained using Langmuir adsorption isotherm. Kinetic modeling to determine the rate of adsorption was studied by using PFO, PSO, and IPD models. Kinetic parameters as evaluated from the kinetic models are shown in Table 4. It can be observed from the table that for both adsorbents (AC and MAC), PSO model was found to be most suitable. For AC and MCA, the values of R2 are 0.999 and 0.960, respectively. 3.6. Effect of Temperature on the Adsorption. The effect of temperature on the adsorption of isonicotinic acid molecules on AC and MAC is shown in Figures 11 and 12, respectively. The solution was prepared taking 6.16 g/L isonicotinic acid with 20 g/L of AC and MAC separately. The results show that with the increase of temperature from 298 to 323 K, the percent removal had increased from 62 to 72.40% with MAC and 55.20 to 63.80% with AC. This can be explained by the opening of the pores due to the rise in temperature of the adsorbent sites allowing more adsorption. The second reason for this could be due to the reduction in the laminar boundary concentration layer which results in decrease in the mass

Figure 11. Effect of solution temperature on the adsorption capacity (●, g/g) and percentage removal (■) of isonicotinic acid (6.16 g/L) using activated carbon (20 g/L) at 298 K.

Figure 12. Effect of solution temperature on the adsorption capacity (●, g/g) and percentage removal (■) of isonicotinic acid (6.16 g/L) using magnetic activated carbon (20 g/L) at 298 K.

transfer resistance and increase in sorption capacity. But with further increase in temperature from 323 to 333 K, the percentage removal decreased in both the cases from 53.8 to 58.4% with AC and 70.4 to 68.0% with MAC. This may be due to the reduction in the attraction forces between the adsorbate and adsorbent caused as a result of increase in the temperature.35 It is also well-known that increase in the temperature results in weakening of the bonds. This factor dominates when the temperature increases significantly. 3.7. Adsorption Thermodynamics: Gibb’s Free Energy Model. A change in the standard Gibb’s free energy (ΔG°) at different temperatures can be determined using eqs 4 and 5. H


Journal of Chemical & Engineering Data ⎛q ⎞ ΔG° = −RT ln⎜ e ⎟ ⎝ Ce ⎠

(4)

ΔG° = ΔH ° − T ΔS°

(5)

■

*E-mail: [email protected]. ORCID

Dipaloy Datta: 0000-0002-2048-9064 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS We would like to thank the Material Research Centre Laboratory of Malaviya National Institute of Technology, Jaipur for providing the necessary facilities to characterize the samples using FTIR, TGA, and FE-SEM along with EDS.

■

Table 5. Thermodynamic Parameters for the Adsorption Process for Both Activated Carbon and Magnetic Activated Carbon ΔH° (J/mol)

ΔS° (J/mol/K)

11 287.8 11 698.5

72.19 75.77

REFERENCES

(1) Mohan, D.; Pittman, C. U. Arsenic Removal from Water/ wastewater Using Adsorbents-A Critical Review. J. Hazard. Mater. 2007, 142, 1−53. (2) Mohan, D.; Pittman, C. U. Activated Carbons and Low Cost Adsorbents for Remediation of Tri- and Hexavalent Chromium from Water. J. Hazard. Mater. 2006, 137, 762−811. (3) Muliwa, A. M.; Leswifi, T. Y.; Onyango, M. S.; Maity, A. Magnetic Adsorption Separation (MAS) Process: An Alternative Method of Extracting Cr(VI) from Aqueous Solution Using Polypyrrole Coated Fe3O4 Nanocomposites. Sep. Purif. Technol. 2016, 158, 250−258. (4) Gopi Kiran, M.; Pakshirajan, K.; Das, G. A New Application of Anaerobic Rotating Biological Contactor Reactor for Heavy Metal Removal under Sulfate Reducing Condition. Chem. Eng. J. 2017, 321, 67−75. (5) Ortega, A.; Oliva, I.; Contreras, K. E.; González, I.; Cruz-Díaz, M. R.; Rivero, E. P. Arsenic Removal from Water by Hybrid ElectroRegenerated Anion Exchange Resin/electrodialysis Process. Sep. Purif. Technol. 2017, 184, 319−326. (6) Yoshikawa, N.; Mikoshiba, S.; Sumi, T.; Taniguchi, S. Model Experimental Study on Cs Removal from Clay Minerals by Ion Exchange under Microwave Irradiation. Chem. Eng. Process. 2017, 115, 56−62. (7) Heberer, T.; Feldmann, D.; Reddersen, K.; Altmann, H.-J.; Zimmermann, T. Production of Drinking Water from Highly Contaminated Surface Waters: Removal of Organic, Inorganic, and Microbial Contaminants Applying Mobile Membrane Filtration Units. Acta Hydrochim. Hydrobiol. 2002, 30, 24−33. (8) Folens, K.; Huysman, S.; Van Hulle, S.; Du Laing, G. Chemical and Economic Optimization of the Coagulation-Flocculation Process for Silver Removal and Recovery from Industrial Wastewater. Sep. Purif. Technol. 2017, 179, 145−151. (9) Sundarapandiyan, S.; Renitha, T. S.; Sridevi, J.; Saravanan, P.; Chandrasekaran, B.; Raju, G. B. Photocatalytic Degradation of Highly Refractive Phenolic Polymer − Mechanistic Insights as Revealed by Electron Spin Resonance (ESR) and Solid-State 13C NMR Spectroscopy. Chem. Eng. J. 2017, 313, 1112−1121. (10) Dipa Ghosh, K. G. B. Adsorption of Methylene Blue on Kaolinite. Appl. Clay Sci. 2002, 20, 295−300. (11) Akarslan, F.; Demiralay, H. Effects of Textile Materials Harmful to Human Health. Acta Phys. Pol., A 2015, 128, 407−408. (12) Jones, K. C. K. C.; de Voogt, P. Persistent Organic Pollutants (POPs): State of the Science. Environ. Pollut. 1999, 100, 209−221. (13) Faulconer, E. K.; von Reitzenstein, N. V. H.; Mazyck, D. W. Optimization of Magnetic Powdered Activated Carbon for Aqueous Hg(II) Removal and Magnetic Recovery. J. Hazard. Mater. 2012, 199− 200, 9−14. (14) Fu, R.; Liu, Y.; Lou, Z.; Wang, Z.; Baig, S. A.; Xu, X. Adsorptive Removal of Pb(II) by Magnetic Activated Carbon Incorporated with Amino Groups from Aqueous Solutions. J. Taiwan Inst. Chem. Eng. 2016, 62, 247−258.

Figure 13. Plot of ΔG versus temperature for activated carbon (■) and magnetic activated carbon (●).

AC MAC

AUTHOR INFORMATION

Corresponding Author

R is the universal gas constant (8.314 J/mol/K), and T is the temperature in K. To determine the values of standard enthalpy (ΔH°) and entropy (ΔS°), a plot between ΔG° and temperature T (Figure 13) was drawn by using eq 5. Values of ΔH° and ΔS° are shown in Table 5.

adsorbent

Article

A positive value of ΔH° (11 287.80 and 11 698.50 J/mol for AC and MAC, respectively) indicated that the adsorption process is endothermic in nature, and the positive value of ΔS° (72.19 and 75.77 J/mol/K for AC and MAC, respectively) showed that there is an increase in the randomness in the adsorption system.27 The positive value of ΔS° indicated an increase in the randomness at the adsorbent−solution interface. Also, it reflects the affinity of adsorbate toward the adsorbent.36,37

■

CONCLUSION A study of separation of iNA from aqueous phase was conducted by adsorbing it on two kinds of adsorbent: AC and MAC. Equilibrium time for both the adsorbents was observed as 120 min. Percent removal was found to increase with increase in adsorbent dosage and initial iNA concentration. Their values were increased at first and then decreased with an increase in the temperature. The adsorption equilibrium is best fitted with the Langmuir isotherm for AC, and with the Temkin isotherm for MAC. Pseudo-second-order fitted kinetic data for both AC and MAC. The impregnation of Fe3O4 ensures easy separation of adsorbent after its use in the separation process. I



Article

(15) Nethaji, S.; Sivasamy, A.; Mandal, A. B. Preparation and Characterization of Corn Cob Activated Carbon Coated with NanoSized Magnetite Particles for the Removal of Cr(VI). Bioresour. Technol. 2013, 134, 94−100. (16) Zhang, G.; Qu, J.; Liu, H.; Cooper, A. T.; Wu, R. CuFe2O4/ activated Carbon Composite: A Novel Magnetic Adsorbent for the Removal of Acid Orange II and Catalytic Regeneration. Chemosphere 2007, 68, 1058−1066. (17) Ai, L.; Huang, H.; Chen, Z.; Wei, X.; Jiang, J. Activated carbon/ CoFe2O4 Composites: Facile Synthesis, Magnetic Performance and Their Potential Application for the Removal of Malachite Green from Water. Chem. Eng. J. 2010, 156, 243−249. (18) Luo, X.; Zhang, L. High Effective Adsorption of Organic Dyes on Magnetic Cellulose Beads Entrapping Activated Carbon. J. Hazard. Mater. 2009, 171, 340−347. (19) Kakavandi, B.; Jonidi, A.; Rezaei, R.; Nasseri, S.; Ameri, A.; Esrafily, A. Synthesis and Properties of Fe3O4-Activated Carbon Magnetic Nanoparticles for Removal of Aniline from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies. Iran. J. Environ. Health Sci. Eng. 2013, 10, 19. (20) Jiang, T.; Liang, Y. D.; He, Y. J.; Wang, Q. Activated carbon/ NiFe2O4Magnetic Composite: A Magnetic Adsorbent for the Adsorption of Methyl Orange. J. Environ. Chem. Eng. 2015, 3, 1740−1751. (21) Mohan, D.; Sarswat, A.; Singh, V. K.; Alexandre-Franco, M.; Pittman, C. U. Development of Magnetic Activated Carbon from Almond Shells for Trinitrophenol Removal from Water. Chem. Eng. J. 2011, 172, 1111−1125. (22) Do, M. H.; Phan, N. H.; Nguyen, T. D.; Pham, T. T. S.; Nguyen, V. K.; Vu, T. T. T.; Nguyen, T. K. P. Activated carbon/ Fe3O4 Nanoparticle Composite: Fabrication, Methyl Orange Removal and Regeneration by Hydrogen Peroxide. Chemosphere 2011, 85, 1269−1276. (23) Zhang, S.; Li, X.-Y.; Chen, J. P. Preparation and Evaluation of a Magnetite-Doped Activated Carbon Fiber for Enhanced Arsenic Removal. Carbon 2010, 48, 60−67. (24) Suzuki, K.; Yasuda, M.; Yamasaki, K. Stability Constants of Picolinic and Quinaldic Acid Chelates of Bivalent Metals. J. Phys. Chem. 1957, 61, 229−231. (25) Broadhurst, L.; Domenico, P Diabetes Technol. Ther. 2006, 8, 677. (26) Datta, D.; Sah, S.; Rawat, N.; Kumar, R. Application of Magnetically Activated Carbon for the Separation of Nicotinic Acid from Aqueous Solution. J. Chem. Eng. Data 2017, 62, 712−719. (27) Datta, D.; Kuyumcu, Ö . K.; Bayazit, Ş. S.; Salam, M. A. Adsorptive Removal of Malachite Green and Rhodamine B Dyes on Fe3O4/Activated Carbon Composite. J. Dispersion Sci. Technol. 2017, 38, 1556−1562. (28) Anyika, C.; Asri, N. A. M.; Majid, Z. A.; Yahya, A.; Jaafar, J. Synthesis and Characterization of Magnetic Activated Carbon Developed from Palm Kernel Shells. Nanotechnol. Environ. Eng. 2017, 2, Article 16, 1−25. (29) Islam, S.; Ang, B. C.; Gharehkhani, S.; Afifi, A. B. M. Adsorption Capability of Activated Carbon Synthesized from Coconut Shell 2016, 20, 1−9. (30) Park, H.; Reddy, J.; Choo, K.; Lee, B. J. Hazard. Mater. 2015, 286, 315−324. (31) Reza, R. A.; Ahmaruzzaman, M. A Novel Synthesis of Fe2Oc3 @ activated Carbon Composite and Its Exploitation for the Elimination of Carcinogenic Textile Dye from an Aqueous Phase. RSC Adv. 2015, 5, 10575−10586. (32) Li, C.; Lu, J.; Li, S.; Tong, Y.; Ye, B. Synthesis of Magnetic Microspheres with Sodium Alginate and Activated Carbon for Removal of Methylene Blue. Materials 2017, 10, 1−14. (33) Oliveira, L. C. A.; Rios, R. V. R. A.; Fabris, J. D.; Garg, V.; Sapag, K.; Lago, R. M. Activated Carbon/iron Oxide Magnetic Composites for the Adsorption of Contaminants in Water. Carbon 2002, 40, 2177−2183.

(34) Ríos-Hurtado, J. C.; Múzquiz-Ramos, E. M.; Zugasti-Cruz, A.; Cortés-Hernández, D. A. Mechanosynthesis as a Simple Method to Obtain a Magnetic Composite (Activated Carbon/Fe3O4) for Hyperthermia Treatment. J. Biomater. Nanobiotechnol. 2016, 7, 19−28. (35) Mohanty, S.; Bal, B.; Das, A.P. Adsorption of Hexavalent Chromium onto Activated Carbon. Austin Journal of Biothechnology and Bioendineering 2014, 1, 1−5. (36) Ahmad, M. A.; Ahmad Puad, N. A.; Bello, O. S. Kinetic, Equilibrium and Thermodynamic Studies of Synthetic Dye Removal Using Pomegranate Peel Activated Carbon Prepared by MicrowaveInduced KOH Activation. Water Resour. Ind. 2014, 6, 18−35. (37) Al-Rashed, S. M.; Al-Gaid, A. A. Kinetic and Thermodynamic Studies on the Adsorption Behavior of Rhodamine B Dye on Duolite C-20 Resin. J. Saudi Chem. Soc. 2012, 16, 209−215. (38) Liu, Z.; Zhang, F.-S.; Sasai, R. Arsenate Removal from Water Using Fe3O4-Loaded Activated Carbon Prepared from Waste Biomass. Chem. Eng. J. 2010, 160, 57−62. (39) Zhu, H. Y.; Fu, Y. Q.; Jiang, R.; Jiang, J. H.; Xiao, L.; Zeng, G. M.; Zhao, S. L.; Wang, Y. Adsorption Removal of Congo Red onto Magnetic cellulose/Fe3O4/activated Carbon Composite: Equilibrium, Kinetic and Thermodynamic Studies. Chem. Eng. J. 2011, 173, 494− 502. (40) Fayazi, M.; Ghanei-Motlagh, M.; Taher, M. A. The Adsorption of Basic Dye (Alizarin Red S) from Aqueous Solution onto Activated Carbon/γ-Fe2O3 Nano-Composite: Kinetic and Equilibrium Studies. Mater. Sci. Semicond. Process. 2015, 40, 35−43. (41) Yang, N.; Zhu, S.; Zhang, D.; Xu, S. Synthesis and Properties of Magnetic Fe3O4-Activated Carbon Nanocomposite Particles for Dye Removal. Mater. Lett. 2008, 62, 645−647. (42) Depci, T. Comparison of Activated Carbon and Iron Impregnated Activated Carbon Derived from Golbasi Lignite to Remove Cyanide from Water. Chem. Eng. J. 2012, 181−182, 467−478. (43) Lagergren, S. Zur Theorie Der Sogenannten Adsorption Geloster Stoffe. Chem. Eng. J. 1898, 24, 1−39. (44) Ho, Y. S.; McKay, G. Pseudo-Second Order Model for Sorption Processes. Process Biochem. 1999, 34, 451−465. (45) Azizian, S. Kinetic Models of Sorption: A Theoretical Analysis. J. Colloid Interface Sci. 2004, 276, 47−52. (46) Findon, A.; McKay, G.; Blair, H. S. Transport Studies for the Sorption of Copper Ions by Chitosan. J. Environ. Sci. Health, Part A: Environ. Sci. Eng. Toxic Hazard. Subst. Control 1993, 28, 173−185. (47) Jansson-Charrier, M.; Guibal, E.; Roussy, J.; Delanghe, B.; Le Cloirec, P. Vanadium (IV) Sorption by Chitosan: Kinetics and Equilibrium. Water Res. 1996, 30, 465−475. (48) Clarke, F. W.; Irving Langmuir, B. Constitution of Solids and Liquids. J. Am. Chem. Soc. 1916, 38, 2221−2295. (49) Freundlich, H. M. F. Ü ber Die Absorption in Lösungen. Z. Phys. Chem. 1906, 57, 385−470. (50) Temkin, M. I. Adsorption Equilibrium and the Kinetics of Processes on Nonhomogeneous Surfaces and in the Interaction between Adsorbed Molecules. Zh. Fiz. Khim. 1941, 15, 296−332.

J


Adsorption Study for the Separation of Isonicotinic Acid from Aqueous

Recommend Documents