Fast Removal of Methylene Blue from Aqueous

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Aug 23, 2013 - pound, which have a variety of scientific and industrial applications. 20. (Ding et ...... hazardous dye, erythrosine, over hen feathers.” J. Colloid ...
Fast Removal of Methylene Blue from Aqueous Solution using Magnetic-Modified Fe3O4 Nanoparticles

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Shiva Dehghan Abkenar 1; Mehdi Khoobi 2; Roghayeh Tarasi 3; Morteza Hosseini 4; Abbas Shafiee 5; and Mohammad R. Ganjali 6

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Abstract: Tannic acid modified super paramagnetic Fe3 O4 nanoparticles (Fe3 O4 -TAN) were synthesized by a simple strategy and were used as adsorbents for removal of methylene blue (MB) from water solution. The prepared magnetic nanoparticles (MNPs) were characterized by Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), thermogravimetric (TGA), and X-ray diffraction (XRD) analyses. The effects of pH, contact time, dye concentration, and temperature on adsorption were determined. The experimental data were analyzed using the Langmuir adsorption model. The data fitted well to the model with maximum adsorption capacities 90.9 mg=g under pH ¼ 10.5. Also, the adsorption kinetics and thermodynamic parameters were studied and evaluated. Adsorption of the MB to nanoparticles reached equilibrium after 25 min. In addition, the external magnetic field could easily separate nanoparticles from water with high separation efficiency. Desorption process of the adsorbed dyes was also investigated. DOI: 10.1061/(ASCE)EE.1943-7870.0000878. © 2014 American Society of Civil Engineers.

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Author keywords: Magnetic separation; Removal; Adsorption; Methylene blue.

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Introduction

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The synthetic dyes represent a relatively large group of organic chemicals that are involved in daily life. The cationic dyes such as methylene blue (MB) are an important group of organic compound, which have a variety of scientific and industrial applications (Ding et al. 2006; Ghica and Brett 2009; Long et al. 2004; Dow et al. 2009). So it would be likely that such chemicals have some undesirable effects on humans as well as on the environment. In order to minimize the potentially harmful effect on humans and the environment arising from the production and applications of cationic dyes, many studies were carried out around the world. Currently, several physical or chemical processes are used to treat dye-laden wastewaters, such as adsorption (Gad and El-Sayed 2009; Ferrero 2010; Li et al. 2010; Mittal et al 2008; Gupta et al 2006), chemical oxidation (Chang et al. 2009), electrochemical oxidation (Zhao et al. 2010), and photocatalytic oxidation

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(Rajeev et al. 2007). Most of dyes are stable to photodegradation, biodegradation, and oxidizing agents (Malik et al. 2007). Therefore, the adsorption process is one of the highly efficient and low-cost methods to remove dyes from water. So far several attempts have been made to lower the concentration of cationic dyes in wastewater, which include using ion exchange membranes (Wu et al. 2008), activated carbon (Karaca et al. 2008), clay (Tahir and Rauf 2006; Weng and Pan 2007), zeolite (Alpat et al. 2008), and other natural materials (Noroozi et al. 2007; Tsai et al. 2007; Mittal et al. 2010). But it is very difficult to purify wastewater due to inefficient adsorption of cationic dyes by adsorbents, high cost of regeneration (Wu et al. 2008), low flow rate (Karaca et al. 2008), and difficulties related to the separation of absorbent from wastewater (Noroozi et al. 2007). Because of these obstacles, nanotechnology is being considered as an attractive and alternative approach to overcome these problems. Magnetic nanoparticles (MNPs) are recognized as efficient adsorbent with large specific surface area and small diffusion resistance (Gupta et al. 2011; Afkhami and Norooz-Asl 2009; Ngomsik et al. 2005). Also, magnetic nanoparticles are suitable for removal of dyes because they can be simply recollected from water with magnetic separation. Magnetic nanoparticles are susceptible to air oxidation (Maity and Agrawal 2007) and easily aggregated in aqueous systems. Recently, some organic substances such as oleic acid (OA), ethylendiaminetetraaceticacid (EDTA) (Warner et al. 2010) and humic acid (HA) (Peng et al. 2012) have been used as iron oxides (such as Fe3 O4 ) core shell to improve the stability of these nanoparticles. The functional groups of the coated particles also have adsorptive effects. In this paper, the authors prepared magnetic sorbent material by direct covalent linkage of magnetite nanoparticles to tannic acid and then these modified nanoparticles were applied to remove methylene blue from the aqueous solution. Tannic acid coating of Fe3 O4 nanoparticles enhances the absorption of methylene blue because of the negative charge of tannic acid. The applicability of these modified nanoparticles was evaluated in view of the effects of solution pH, adsorbent dosage, the sorption kinetic, and thermodynamic.

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Assistant Professor, Dept. of Chemistry, Islamic Azad Univ., Savadkooh Branch, Mazandaran, Iran (corresponding author). E-mail: [email protected] 2 Assistant Professor, Dept. of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran Univ. of Medical Sciences, Tehran 14176, Iran. E-mail: mehdi.khoobi@gmail .com 3 Ph.D. Student, Chemistry Dept., Zanjan Univ., P.O. Box 45195-313, Zanjan, Iran. E-mail: [email protected] 4 Assistant Professor, Dept. of Life Science Engineering, Faculty of New Sciences and Technologies, Univ. of Tehran, Tehran, Iran. E-mail: [email protected] 5 Professor, Dept. of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran Univ. of Medical Sciences, Tehran 14176, Iran. E-mail: [email protected] 6 Professor, Center of Excellence in Electrochemistry, Faculty of Chemistry, Univ. of Tehran, Tehran, Iran. E-mail: [email protected] Note. This manuscript was submitted on August 23, 2013; approved on June 23, 2014No Epub Date. Discussion period open until 0, 0; separate discussions must be submitted for individual papers. This paper is part of the Journal of Environmental Engineering, © ASCE, ISSN 0733-9372/ (0)/$25.00. © ASCE

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Experimental

Synthesis of Magnetic-Modified Nanoparticles

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Instrumentation

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The pH was controlled by Metrohm pH meter Model 713, and Shimadzoλ 25 double beam spectrophotometer was used for the detection of dye concentration in the solution. The infrared (IR) spectra was taken using a Nicolet Fourier transform IR (FT-IR) Magna 550 spectrographs (KBr disks) (Nicolet, Madison, Wisconsin) within 400–4,000 cm−1 . An EM208 Philips Company transmission electron microscopy (TEM) was used for TEM analysis. Samples were prepared by placing a droplet (1 μL) of nanocomposite dispersion latex, along with a droplet of water, on a copper grid covered by Formvar foil (200 mesh), then dried and analyzed. Thermogravimetric analysis (TGA) was performed using a TGA Q50 thermogravimetric analyzer of a TA instrument with a heating ramp of 10°C min−1 under argon flow from room temperature to 800°C. The morphological analysis by X-ray diffraction (XRD) was performed on XPert MPD advanced diffractometer using Cu (K α ) radiation (wavelength: 1.5406 A°) at room temperature in the range of 2θ from 4 to 120° with a scanning rate of 0.02° s−1 .

Preparation of Fe3 O4 MNPs Fe3 O4 nanoparticles were synthesized via the coprecipitation of Fe2þ and Fe3þ ions (molar ratio 1∶2) in alkali solution. FeCl3 · 6H2 O (4.32 gr) and FeCl2 · 4H2 O (1.60 g) were dissolved in deionized (DI) water (20 mL) under a nitrogen atmosphere with vigorous stirring using a mechanical stirrer. NH3 · H2 O (28% by weight, 25 mL) was subsequently added dropwise to the solution under vigorous stirring as the solution was heated to 70°C to obtain a black precipitate of Fe3 O4 .The reaction was continuously stirred for 1 h at room temperature and then heated to 80°C for 2 h. During the reaction process, the pH was maintained at approximately 10 and oxygen was removed from the solution by blowing N2 gas through the reaction medium. The black powder obtained was separated by applying an external magnet and washed several times with DI water and ethanol to remove any excess ions and salts from the suspension, and then dried at 70°C in vacuum for 24 h (Mu et al. 2010).

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Reagents and Solutions

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All chemicals were reagent grade and purchased from Fluka and Merck chemical companies. Double distilled water (DDW) was used throughout the study. The pipettes and vessels used for trace analysis were kept in dilute nitric acid for at least 24 h and subsequently washed four times with DDW before use. The stock solution of dye was prepared by dissolving dye powder in DDW and diluted to prepare the desired concentration of dye solutions.

Grafting of Tannic Acid onto the Fe3 O4 MNPs The procedure for preparation of tannic acid modified super paramagnetic Fe3 O4 nanoparticles (Fe3 O4 -TAN) is illustrated in Fig. 1. TAN (10 mmol, 3.58 g) was added to the as-prepared Fe3 O4 MNPs (2 g), which well dispersed in dry toluene (20 mL), and the mixture was refluxed at boiling temperature of toluene (110°C) for 24 h. Fe3 O4 -TAN were separated by an external magnet and washed with toluene and acetone repeatedly and drying at 80°C in vacuum for 24 h (Gu et al. 2005; Zhou et al. 2012).

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For each experimental run, 10 mg of magnetic nanoparticles was added to 20 mL of 20 mg L−1 of cationic dye MB solutions with predetermined concentration. The pH was adjusted at 10.5 with

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Dyes Removal Experiment

Fig. 1. Schematic illustration of preparation of Fe3 O4 -TAN

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ðCo − Ce ÞV m

ð2Þ

where Co and Ce = initial and equilibrium concentrations of dye (mgL−1 ); m = mass of composite (g); and V = volume of solution (L).

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Results and Discussion

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Adsorbent Characterization

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The TAN grafted onto the magnetic nanospheres was studied using FT-IR spectroscopy [Figs. 2(a–c)]. As can be seen from Fig. 2(a), the spectrum of the Fe3 O4 MNPs shows a peak at 584 cm−1 , which is attributed to the Fe─O vibration and the strong OH band at approximately 3,450 cm−1, which is assigned to the stretching

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Fig. 2. IR spectra of (a) Fe3 O4 ; (b) tannic acid; (c) Fe3 O4 -TAN © ASCE

Fig. 3. TEM image of Fe3 O4 -TAN

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vibrations of Fe─OH groups absorbed on the surface of Fe3 O4 MNPs and the water that was not removed from the surface of the MNPs. The IR curve of free TAN shows C═O stretching vibrations at 1,711 cm−1 , broad peak at approximately 3,433 cm−1 , which is attributed to the OH group. Moreover, bonds at 1,610, 1,540, and 1,450 cm−1 are stretch vibrations absorption of C═C in benzene. A similar pattern could also be observed in the spectrum of Fe3 O4 -TAN [Fig. 2(c)], which indicates that the TAN was successfully grafted onto the Fe3 O4 MNPs. The TEM (Fig. 3) images show that the Fe3 O4 -TAN are monocrystalline with spherical shapes and nearly uniform distribution of particle size less than 50 nm. TGA was used to confirm the coating formation efficiency by grafted TAN in synthesis steps [Fig. 4(a)]. The weight loss during heating from 50 to approximately 200°C is attributed to the loss of loosely bound water and organic solvent. Comparison between the TGA results of Fe3 O4 MNPs and Fe3 O4 -TAN clearly show the percentage of TAN grafting density is approximately 13.43%. The crystalline structures of the obtained Fe3 O4 -TAN were determined by XRD analysis [Fig. 4(b)]. The position and relative intensity of all the diffraction peaks correctly were accordance with those of standard Fe3 O4 (Zeng et al. 2007). XRD analysis shows that Fe3 O4 -TAN MNPs are in the form of inverse spinel Fe3 O4 with a face-centered cubic structure, and the sample has a cubic crystal system. Meanwhile, no characteristic peaks of impurities were observed in the XRD spectrum.

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Co and Ct represent the initial and final (after adsorption) concentration of dye (mgL−1 ), respectively. All the experiments were performed at room temperature. The effects of pH, contact time, dye concentration, and temperature on adsorption were investigated. The adsorption kinetic was determined by analyzing adsorption capacity of the aqueous solution at different time intervals. For adsorption isotherm, the dye solution of different concentration in the range of 10–100 mgL−1 was agitated until the equilibrium was achieved. The effect of temperature on the adsorption characteristics was studied by determining the adsorption isotherms at 298, 318, 338, and 343 K. The adsorbed amounts (q) of dye were calculated by the following equation:

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0.1 mol L−1 NaOH solutions. The mixed solution was gently shaken at room temperature for 15 min. Subsequently, the magnetic nanoparticles with adsorbed dyes were separated from the mixture via a permanent handheld magnet. The residual amounts of dye in the solution were determined spectrophotometrically at 665 for MB. The adsorption percentage for dye, i.e., the dye removal efficiency, was determined using the following:   ðCo − Ct Þ × 100 ð1Þ %R ¼ Co

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Effect of pH

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The effect of pH on the adsorption of dye is shown in Fig. 5 from pH 3.0 to 11.0. The pH was adjusted by HCl and NaOH and measured by digital pH meter. The pH may affect both aqueous chemistry and surface binding sites of the adsorbent. The adsorption of MB was increased at higher pH values. Hence, pH ¼ 10.5 was chosen for subsequent experiments. This phenomenon can be explained on the basis of added negative charges on the nanoparticles surface, which could enhance the electrostatic interaction of nanoparticles and cationic dye MB.

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Effect of the Amount of Adsorbent

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The effect of the amount of modified nanoparticles as adsorbent on the removal of MB was determined at room temperature and at pH 10.5 by varying the adsorbent amount from 0.006 to 0.03 g in 10 mL solution of 20 mgL−1 of MB. The results show (Fig. 6) that the removal efficiency of MB was increased by increasing the amount of absorbent due to the availability of higher adsorption sites. The 0.015 g modified nanoparticles had a removal efficiency

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Fig. 6. Percentage of dye removal using different amount of modified nanoparticles for MB

Fig. 4. (a) TGA spectra; (b) XRD spectra of Fe3 O4 -TAN

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of 95% and the adsorption reached a maximum with 0.02 g of adsorbent with maximum percentage removal approximately 97%.

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Adsorption Kinetics

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The effect of contact time on the amount of adsorbed MB was investigated at the initial concentration of 20 mgL−1 at pH 10.5 at room temperature. The concentration of MB was measured using © ASCE

Fig. 7. Effect of contact time on the adsorption of MB on modified nanoparticles

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spectrophotometer. The nanoparticles adsorption was measured periodically at 5, 10, 15, 25, and 40 min. Fig. 7 shows the effect of contact time on the adsorption capacity of MB by the modified nanoparticles. It is clear that the adsorption capacity increases rapidly during the initial adsorption stage and then continues to increase at a relatively slow speed with contact time and reaches equilibrium point after 25 min. To investigate the adsorption mechanism of MB for modified nanoparticles, two kinetic models, pseudo-first-order kinetic model and pseudo-second-order kinetic model, were considered to find the best fitted model for the experimental data. The pseudo-first-order Lagergren equation is given by (Lagergren 1898)

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logðqe − qt Þ ¼ log qe −

Fig. 5. Effect of pH on the adsorption of MB onto the modified nanoparticles

k1 t 2.303

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where k1 = pseudo-first-order rate constant (min−1 ); and qe and qt = amounts of dye adsorbed (mg g−1 ) at equilibrium and at time t (min). The pseudo-second-order model can be expressed as (Ho and McKay 1998)

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t 1 t ¼ þ 2 q t k2 q e q e

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where k2 (g mg−1 min−1 ) = rate constant of the pseudo-secondorder adsorption. 4

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Fig. 8. (a) Pseudo-first-order kinetics; (b) pseudo-second-order kinetics of adsorption MB on the modified nanoparticles

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Kinetic constants obtained by linear regression for the two models (Fig. 8). The results are listed in Table 1. The correlation coefficients (R2 ) for the pseudo-first-order kinetic model are relatively low and the calculated qe values (qe;cal ) from the pseudo-first-order kinetic model do not agree with the experimental data (qe;exp ), suggesting the adsorption of MB onto the nanoparticles cannot be applied to a first-order model. For the pseudosecond-order kinetic model, the R2 value is 0.999 for MB and the qe;cal values agreed with the qe;exp values very well. This indicates the applicability of the second-order model to describe the adsorption process of MB onto the modified nanoparticles.

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Fig. 9. Langmuir adsorption isotherm of MB for modified nanoparticles

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In order to optimize the use of modified nanoparticles, it is important to establish the most appropriate adsorption isotherm. The adsorption capacities of the as-obtained modified nanoparticles to dye were measured individually at pH 10.5 with varied MB concentration. The amounts of dyes in the solution were determined after equilibration. The result is shown in Fig. 9. The data of the dye adsorbed at equilibrium (qe , mg=g) and the equilibrium dye concentration (Ce , mg=L) were fitted to the linear form of Langmuir adsorption model (Langmuir 1916)

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Ce 1 C ¼ þ e qe bqm qm

Fig. 10. van‘t Hoff plot of ln K d versus 1=T

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where qm = maximum adsorption capacity corresponding to complete monolayer coverage; and b = equilibrium constant (L=mg). The data fit well to the model with correlation coefficients (R2 ) of 0.990, and the maximum adsorption capacity in the studied concentration range is 90.9 mg=g.

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Adsorption Thermodynamic

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Thermodynamic parameters, such as changes in Gibbs free energy (ΔG°, kJ mol−1 ), enthalpy (ΔH°, kJ mol−1 ), and entropy (ΔS°, J mol−1 K−1 ) are the actual indicators for practical applications. Adsorption thermodynamic was evaluated with respect to different temperatures (298, 318, 338, and 343 K). The results are shown in Fig. 10. To obtain the thermodynamic parameters of dyes adsorption, the values of K d were calculated at different temperature according to the van‘t Hoff equation (Giles et al. 1960) as follows:

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ð6Þ

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Table 1. Adsorption Kinetic Parameters of MB Adsorption onto the Modified Nanoparticles

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Pseudo-first-order −1

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Pseudo-second-order −1

qe;cal (g mg

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Experimental data −1

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0.999

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ΔG° (kJ mol−1 )

ΔH° (kj mol−1 )

ΔS° (J mol−1 K1 )

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Acetone Ethanol Acetonitrile Ethyl acetate

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ln K d ¼

ΔS° ΔH° − R RT

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where K d = distribution coefficient; T = temperature (K); R = gas constant (8.3145 J mol−1 K−1 ); and Ce and qe = equilibrium concentration in aqueous phase (mg L−1 ) and the amount of dyes adsorbed per unit mass of the adsorbent (mg g−1 ), respectively. The calculated results are listed in Table 2. The negative values of ΔG° indicate that the adsorption process is a spontaneous reaction. The positive values of enthalpy change confirm the endothermic nature of the adsorption process and the positive values of ΔS° reflect an increase in randomness at the solid-solution interface during the adsorption of MB onto the modified nanoparticles.

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Desorption and Reuse Study

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The reusability of adsorbent is of great importance as a costeffective process in water treatment. So the potential regeneration of the adsorbent is also investigated by washing the loaded dyes on the modified nanoparticles using 10.0 mL of acetone, ethanol, acetonitrile, and ethyl acetate. After extraction except with ethyl acetate, the adsorbent could be regenerated and reused in dye adsorption. The results are given in Table 3. The equilibrium of desorption was achieved rapidly within approximately 10 min,

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Capacity factor (mg g−1 )

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Fe3 O4 -TAN Fe3 O4 @C

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Magnetic-modified multiwalled carbon nanotubes Magnetic multiwalled carbon nanotubes Magnetic multiwalled carbon nanotubes (filled with Fe2 O3 ) Magnetic grapheme-carbon nanotube composite Tea waste Fe(III)/Cr(III) hydroxide

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Proposed work Zhang and Kong (2011) Ai et al. (2011) Madrakian et al. (2011)

15.87

Gong et al. (2009)

42.3

Qu et al. (2008)

65.79

Wang et al. (2014)

85.16 22.8

Uddin et al. (2009) Namasivayam and Sumithra (2005)

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References

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Acknowledgments

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The financial support of this work by the Iran National Science Foundation (INSF 91002199) is gratefully acknowledged.

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References

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Afkhami, A., and Norooz-Asl, R. (2009). “Removal, preconcentration and determination of Mo(VI) from water and wastewater samples using magnetite nanoparticles.” Colloids. Surf. A, 346(1–3), 52–57. Ai, L., Zhou, Y., and Jiang, J. (2011). “Removal of methylene blue from aqueous solution by montmorillonite/CoFe2 O4 composite with magnetic separation performance.” Desalination, 266(1–3), 72–77. Alpat, K. S., Ozbayrak, O., Alpat, S., and Akcay, H. (2008). “The adsorption kinetics and removal of cationic dye, Toluidine Blue O, from aqueous solution with Turkish zeolite.” J. Hazard. Mater., 151(1), 213–220. Chang, S. H., Wang, K. S., Li, H. C., We, M. Y., and Chou, J. D. (2009). “Enhancement of Rhodamine B removal by low-cost fly ash sorption with Fenton pre-oxidation.” J. Hazard. Mater., 172(2–3), 1131–1136. Ding, Y., Zhang, X., Liu, X., and Guo, R. (2006). “Adsorption characteristics of thionine on gold nanoparticles.” Langmuir, 22(5), 2292–2298. Dow, W. P., et al. (2009). “Microvia filling by copper electroplating using diazine black as a leveler.” Electrochim. Acta, 54(24), 5894–5901. Ferrero, F. (2010). “Adsorption of methylene blue on magnesium silicate: Kinetics, equilibria and comparison with other adsorbents.” J. Environ. Sci., 22(3), 467–473. Gad, H. M. H., and El-Sayed, A. A. (2009). “Activated carbon from agricultural by-products for the removal of Rhodamine- B from aqueous solution.” J. Hazard. Mater., 168(2–3), 1070–1081. Ghica, M. E., and Brett, C. M. A. (2009). “Poly (brilliant cresyl blue) modified glassy carbon electrodes: Electrosynthesized, characterization and application in biosensors.” J. Electroanal. Chem., 629(1–2), 35–42. Giles, C. H., Macewan, T. H., Nakhwa, S. N., and Smith, D. (1960). “Studies in adsorption. Part XI. A system of classification of solution adsorption isotherms, and its use in diagnosis of adsorption mechanisms

Table 4. Comparison of the Maximum Capacity Factor of MB onto Various Adsorbents

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Conclusions

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In this study, a low-cost super magnetic adsorbent, Fe3 O4 -TAN nanoparticles, was prepared by a coprecipitation procedure with cheap and environmentally friendly iron salt and tannic acid. The prepared nanoparticles could be well dispersed in the aqueous solution and easily separated from the solution using an external magnet after adsorption. The adsorbent was very effective in removing dye and the adsorption of dyes to nanoparticles was fast and agreed well with the Langmuir adsorption model with maximum adsorption capacities of 90.9 mg=g. Table 4 compares the adsorption capacities of the adsorbent in this work with different adsorbents previously used for removal of MB. It can be seen form Table 4 that the adsorption capacity of Fe3 O4 -TAN is higher than that of many other previously reported adsorbents. Further, the cost of magnetic nanoparticle preparation is very low, the functionalization is easy available, and the process of purifying water pollution is clean and safe using magnetic nanomaterials. Hence, this methodology can be suitable for the large-scale removal of the pollutant dyes from water.

Table 3. Effect of Type of Eluting Agent on Recovery Percent for Dye Adsorbed on the Modified Nanoparticles (N ¼ 3)

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similar to the adsorption equilibrium. After the elution of the adsorbed dyes, the adsorbent was washed with DDW and dried under vacuum at 25°C and reused for dye removal. The reusability of the sorbent was greater than three cycles without any loss of sorption capacity. Therefore, the modified nanoparticles can be a good reusable and economical sorbent.

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Table 2. Values of Thermodynamic Parameters of Adsorption of MB Adsorption onto the Modified Nanoparticles

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Namasivayam, C., and Sumithra, S. (2005). “Removal of direct red 12B and methylene blue from water by adsorption onto Fe (III)/Cr (III) hydroxide, an industrial solid waste.” J. Environ. Manage., 74(3), 207–215. Ngomsik, A. F., Bee, A., Draye, M., Cote, G., and Cabuil, V. (2005). “Magnetic nano- and microparticles for metal removal and environmental applications: A review.” C.R. Chim., 8(6–7), 963–970. Noroozi, B., Sorial, G. A., Bahrami, H., and Arami, M. (2007). “Equilibrium and kinetic adsorption study of a cationic dye by a natural adsorbent—Silkworm pupa.” J. Hazard. Mater., 139(1), 167–174. Peng, L., et al. (2012). “Modifying Fe3 O4 nanoparticles with humic acid for removal of Rhodamine B in water.” J. Hazard. Mater., 209–210, 193–198. Qu, S., Huang, F., Yu, S., Chen, G., and Kong, J. (2008). “Magnetic removal of dyes from aqueous solution using multi-walled carbon nanotubes filled with Fe2 O3 particles.” J. Hazard. Mater., 160(2–3), 643–647. Rajeev, J., Megha, M., Shalini, S., and Alok, M. (2007). “Removal of the hazardous dye Rhodamine B through photocatalytic and adsorption treatments.” J. Environ. Manage., 85(4), 956–964. Tahir, S. S., and Rauf, N. (2006). “Removal of a cationic dye from aqueous solutions by adsorption onto bentonite clay.” Chemosphere, 63(11), 1842–1848. Tsai, W. T., Hsub, H. C., Su, T. Y., Lin, K. Y., Lin, C. M., and Dai, T. H. (2007). “The adsorption of cationic dye from aqueous solution onto acid-activated andesite.” J. Hazard. Mater., 147(3), 1056–1062. Uddin, M. T., Islam, M. A., Mahmud, S., and Rukanuzzaman, M. (2009). “Adsorptive removal of methylene blue by tea waste.” J. Hazard. Mater., 164(1), 53–60. Wang, P., Cao, M., Wang, C., Ao, Y., Hou, J., and Qian, J. (2014). “Kinetics and thermodynamics of adsorption of methylene blue by a magnetic graphene-carbon nanotube composite.” Appl. Surf. Sci., 290, 116–124. Warner, C. L., et al. (2010). “High-performance, superparamagnetic, nanoparticle-based heavy metal sorbents for removal of contaminants from natural waters.” Chem. Sus. Chem., 3(6), 749–757. Weng, C. H., and Pan, Y. F. (2007). “Adsorption of a cationic dye (methylene blue) onto spent activated clay.” J. Hazard. Mater., 144(1–2), 355–362. Wu, J. S., Liu, C. H., Chu, K. H., and Suen, S. Y. (2008). “Removal of cationic dye methyl violet 2B from water by cation exchange membranes.” J. Membr. Sci., 309(1–2), 239–245. Zeng, H., Lai, Q., Liu, X., Wen, D., and Ji, X. (2007). “Factors influencing magnetic polymer microspheres prepared by dispersion polymerization.” J. Appl. Polym. Sci., 106(5), 3474–3480. Zhang, Z., and Kong, J. (2011). “Novel magnetic Fe3 O4 @C nanoparticles as adsorbents for removal of organic dyes from aqueous solution.” J. Hazard. Mater., 193, 325–329. Zhao, K., Zhao, G., Li, P., Gao, J., Lv, B., and Li, D. (2010). “A novel method for photodegradation of high–chroma dye wastewater via electrochemical pre-oxidation.” Chemosphere, 80(4), 410–415. Zhou, L., Zheng, L., Yuan, J., and Wu, S. (2012). “Synthesis and characterization of thermo-sensitive magnetite-Au nanocomposites.” Mater. Lett., 78, 166–169.

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and in measurement of specific surface areas of solids.” J. Chem. Soc., 10, 3973–3993. Gong, J. L., et al. (2009). “Removal of cationic dyes from aqueous solution using magnetic multi-wall carbon nanotube nanocomposite as adsorbent.” J. Hazard. Mater., 164(2–3), 1517–1522. Gu, H. W., Xu, K. M., Yang, Z. M., Chang, C. K., and Xu, B. (2005). “Synthesis and cellular uptake of porphyrin decorated iron oxide nanoparticles—A potential candidate for bimodal anticancer therapy.” Chem. Commun., 42(34), 4270–4272. Gupta, V. K., Agarwal, S., and Saleh, T. A. (2011). “Chromium removal by combining the magnetic properties of iron oxide with adsorption properties of carbon nanotubes.” Water Res., 45(6), 2207–2212. Gupta, V. K., Mittal, A., Kurup, L., and Mittal, J. (2006). “Adsorption of a hazardous dye, erythrosine, over hen feathers.” J. Colloid Interface Sci., 304(1), 52–57. Ho, Y. S., and McKay, G. (1998). “Sorption of dye from aqueous solution by peat.” Chem. Eng. J., 70(2), 115–124. Karaca, S., Gurses, A., Acıkyıldız, M., and Ejder, M. (2008). “Adsorption of cationic dye from aqueous solutions by activated carbon.” Microp. Mesop. Mater., 115(3), 376–382. Lagergren, S. (1898). “Zurtheorie der sogenannten adsorption gel.osterstoffe. KungligaSvenskaVetens-kapsakademiens.” Handlingar, 24(4), 1–39. Langmuir, I. (1916). “The constitution and fundamental properties of solids and liquids.” JACS, 38(11), 2221–2295. Li, L., Liu, S., and Zhu, T. (2010). “Application of activated carbon derived from scrap tires for adsorption of Rhodamine B.” J. Environ. Sci., 22(8), 1273–1280. Long, X., Bi, S., Tao, X., Wang, Y., and Zhao, H. (2004). “Resonance Rayleigh scattering study of the reaction of nucleic acids with thionine and its analytical application.” Spectrochem. Acta A, 60(1–2), 455–462. Madrakian, T., Afkhami, A., Ahmadi, M., and Bagheri, H. (2011). “Removal of some cationic dyes from aqueous solutions using magnetic-modified multi-walled carbon nanotubes.” J. Hazard. Mater., 196, 109–114. Maity, D., and Agrawal, D. C. (2007). “Synthesis of iron oxide nanoparticles under oxidizing environment and their stabilization in aqueous and non-aqueous media.” J. Magn. Magn. Mater., 308(1), 46–55. Malik, R., Ramteke, D. R., and Wate, S. R. (2007). “Adsorption of malachite green on ground nut shell waste based powdered activated carbon.” Waste Manage., 27(9), 1129–1138. Mittal, A., Gupta, V. K., Malviya, A., and Mittal, J. (2008). “Process development for the batch and bulk removal and recovery of a hazardous, water-soluble azo dye (Metanil Yellow) by adsorption over waste materials (bottom ash and de-oiled soya).” J. Hazard. Mater., 151(2–3), 821–832. Mittal, A., Mittal, J., Malviya, A., Kaur, D., and Gupta, V. K. (2010). “Adsorption of hazardous dye crystal violet from wastewater by waste materials.” J. Colloid Interface Sci., 343(2), 463–473. Mu, B., Liu, P., Dong, Y., Lu, C., and Wu, X. (2010). “Superparamagnetic pH-sensitive multilayer hybrid hollow microspheres for targeted controlled release.” J. Polym. Sci. Part A: Polym. Chem., 48(14), 3135–3144.

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Queries 1. Please provide the ASCE Membership Grades for the authors who are members.

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2. Please provide the poastal code for all the affiliation except second and fifth affiliations. 3. “Iran” was added to the first author’s affiliation. Please verify if this is correct.

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4. NEW! ASCE Open Access: Authors may choose to publish their papers through ASCE Open Access, making the paper freely available to all readers via the ASCE Library website. ASCE Open Access papers will be published under the Creative CommonsAttribution Only (CC-BY) License. The fee for this service is $1750, and must be paid prior to publication. If you indicate Yes, you will receive a follow-up message with payment instructions. If you indicate No, your paper will be published in the typical subscribed-access section of the Journal.

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5. “FT-IR,” “TEM,” “TGA,” and “XRD” have been written out as “Fourier transform infrared,” “transmission electron microscopy,” “thermogravimetric,” and “X-ray diffraction,” respectively. Please verify if these are correct. 6. Please write out “TA” in “TA instrument” 7. Please write out “MPD”

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8. “0.02° S^-1” has been changed to “0.02° s^-1.” Please verify if this is correct. 9. “TAN” was written out as “Tannic Acid.” Please verify if this is correct.

10. “ : : : in vacuum for 24” has been changed to “in vacuum for 24 h.” Please verify if this is correct. 11. Display equations have been numbered. Please confirm.

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12. “3,433” has been changed to “3,433 cm^-1.” Please verify if this is correct. 13. Issue number '1-3' has been inserted in Ai et al. (2011) Please check and confirm the edit made here.

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14. A check of online databases revealed a possible error in Ding et al. (2006). The issue has been changed from '1' to '5'. Please confirm this is correct. 15. Please provide the issue number for Ref. Giles et al. (1960). 16. Issue number '2-3' has been inserted in Gong et al. (2009). Please check and confirm the edit made here.

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17. Issue number '6' has been inserted in Gupta et al. (2011). Please check and confirm the edit made here. 18. Issue number '1' has been inserted in Gupta et al. (2006). Please check and confirm the edit made here. 19. Please translate Lagergren (1898) into English.

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20. Please provide the issue number for Ref. Madrakian et al. (2011). 21. Issue number '2-3' has been inserted in Mittal et al. (2008). Please check and confirm the edit made here. 22. Issue number '2' has been inserted in Mittal et al. (2010). Please check and confirm the edit made here.

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23. Issue number '3' has been inserted in Namasivayam and Sumithra (2005). Please check and confirm the edit made here. 24. Please provide the issue number for Peng et al. (2012). 25. Issue number '2-3' has been inserted in Qu et al. (2008). Please check and confirm the edit made here. 26. Issue number '1' has been inserted in Uddin et al. (2009). Please check and confirm the edit made here. 27. Please provide the issue number for Ref. Wang et al. (2014). © ASCE

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28. Please provide the issue number for Ref. Zhang and Kong (2011).

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29. A check of online databases revealed a possible error in Zhang and Kong (2011). The last page number has been changed from '362' to '329'. Please confirm this is correct.

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30. Please provide the issue number for Ref. Zhou et al. (2012).

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