Synthesis and Evaluation of the Effectiveness of Multi-component Magnetic/Carbon Nano Composite in Removing Heavy Metals from Aqueous Solutions

Subject Areas : Journal of Nanoanalysis

Alireza Vahidi ¹ , Mona Eghtefari ² , Fariba Tadayon ³

1 - Department of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, Iran
2 - Department of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, Iran
3 - 2Department of Chemistry, North Tehran Branch, Islamic Azad University, Tehran, Iran

Received: 2024-06-04 Accepted : 2024-09-26 Published : 2024-05-31

Keywords: Mercury, Surface Adsorption, Magnetic Nanoparticles, Carbon nanotube,

Abstract :

Population growth, industrial development and technology transfer are among the factors of increasing water consumption and waste water production in communities and environmental pollution. Today, this pollution has become a big problem, which has made it necessary to invest in water treatment. Heavy metals are one of the most problematic and dangerous pollutants for the environment and humans. Mercury is considered as a global pollutant and a very toxic element due to its accumulation effect and high persistence in the environment. To remove toxic metals, the adsorbents that are easy and fast to separate and do not cause secondary pollution are preferred. In this study, a modified magnetic carbon nanotube has been prepared and used to remove mercury from polluted water. The physical, chemical and morphological characteristics of the adsorbent were determined with FT-IR and FESEM analyses. In the optimal conditions of pH=6, ambient temperature, 0.1 g of adsorbent, concentration of 10 ppm and time of 60 minutes, the adsorption efficiency was 96%.

References:

[1] F. Tadayon, A. Katebi, A. Afkhami, Y. Panahi & H. Bagheri, A new potentiometric sensor based on a high-performance composite for nanomolar determination of mercury (II) in environmental samples, International Journal of Environmental Analytical Chemistry, 94(9), (2014), 901-915.
[2] Sh. Motahar, M. Saber-tehrani, P. Aberoomand Azar and F. Tadayon, Preconcentration and separation of ultra-trace amounts of mercury(ii) using ultrasound-assisted cloud point-micro solid phase extraction based on modified silica aerogel with [1-(3,5-dicholorophenyl)-3(2-ethoxyphenyl)] triazene, J. Chil. Chem. Soc., 63(4), (2018).
[3] Asoh, A. P., et al. (2023). The effects of mercury exposure on human health: A systematic review. Environmental Research, 120, 115120.
[4] Liu, B., et al. (2024). Mercury in the environment: Sources, transport, fate, and effects. Science of the Total Environment, 914, 186836.
[5] F. Tadayon, M. Saber-Tehrani and Sh. Motahar, Selective removal mercury (II) from aqueous solution using silica aerogel modified with AMTT, Korean J. Chem. Eng., 30(3), (2013), 642-648.
[6] A. Abdollahi, M. Amirkavehei, M. M. Gheisari and F. Tadayon, Trace mercury determination in drinking and natural water after preconcentration and separation by DLLME-SFO method coupled with cold vapor atomic absorption spectrometry, 16th international conference on heavy metals in the environment, Rome, Italy, September 22–27, (2012).
[7] A. Abdollahi, F. Tadayon and M. Amirkavei, Evaluation and determination of heavy metals (mercury, lead and cadmium) in human breast milk, 16th international conference on heavy metals in the environment, Rome, Italy, September 22–27, (2012).
[8] F. Tadayon and Sh. Motahar, Preconcentration of mercury in human hair by modified silica aerogel nanoparticles, Academic Research International, 2(2), (2012).
[9] Androutsi, E., & Mourkogiannis, T. (2023). Recent advances in covalently bonded ceramic/polymer nanocomposites. Progress in Materials Science, 138, 101072.
[10] Meng, Q., Liu, Z., Fu, S., & Zhu, Z. (2024). Interfacial design in 2D nanocomposites: A critical review. Chemical Society Reviews, 53, 1108-1142.
[11] Mohebpour, S., & Vahdat, S. M. (2023). Nanocomposites: A review. Materials Science and Engineering: R: Reports, 120, 1-25.
[12] Shah, T. A., & Asif, H. M. (2023). Nanocomposites in the food packaging industry: A review. Critical Reviews in Food Science and Nutrition, 63 (18), 3322-3342.
[13] Blazdell, L., & Petrova, T. (2024). Polymer nanocomposites for electromagnetic interference shielding. Nanotechnology Reviews, 13 (1), 1-20.
[14] Zhu, J., Zhu, H., & Jia, D. (2023). Biopolymer nanocomposites for biomedical applications. Progress in Polymer Science, 135, 102025.
[15] Geng, H., Zhao, S., Zhang, L., Cheng, Q., & Tang, Z. (2024). High-performance and multifunctional nanocomposites for structural health monitoring: A review. Sensors and Actuators, A: Physical, 390, 111588.
[16] Chen, S., Zhu, W., Zhao, X., Xu, J., & Yang, H. (2023). High-performance and multifunctional graphene-based nanocomposites. Journal of Materials Science & Technology, 97, 17-43.
[17] Chandrasekhar, A. V., Sreeprasad, T. S., & Gupta, N. (2024). Fullerenes and their derivatives as nanofillers in polymer nanocomposites. Progress in Polymer Science, 140, 101381.
[18] Zhu, J., Zhu, H., & Jia, D. (2023). Biopolymer nanocomposites for biomedical applications. Progress in Polymer Science, 135, 102025.
[19] Blazdell, L., & Petrova, T. (2024). Polymer nanocomposites for electromagnetic interference shielding. Nanotechnology Reviews, 13 (1), 1-20.
[20] Liu, T., Li, L., Zhou, C., & Deng, Y. (2023). Functional magnetic nanocomposites for biomedical applications. Materials Today Bio, 18, 100400.
[21] Kudrinski, E., Hernández-Vacheco, E., Muñoz-Espí, C., & Ruiz-García, J. (2023). Magnetic nanocomposites: Promising tools for hyperthermia cancer treatment. International Journal of Pharmaceutics, 656, 123823.
[22] F. Tadayon, M. Hosseini and Sh. Motahar, Nanocomposite silica aerogel activated carbon: preparation, characterization and application to remove lead(II) from aqueous solutions, Journal of the Chinese Article Chemical Society, 59, (2012).

Full-Text:



RESEARCH ARTICLE

J. Nanoanalysis., 10(2):525-532, Spring 2023

 

 

Synthesis and Evaluation of the Effectiveness of Multi-component Magnetic/Carbon Nano Composite in Removing Heavy Metals from Aqueous Solutions
Alireza Vahidi 1, Mona Eghtefari 1 , Fariba Tadayon*,1
1Department of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, Iran
ARTICLE INFO   Article History: Received 2024-06-04 Accepted 2024-09-26 Published 2023-05-05     Keywords: Mercury, Surface Adsorption, Magnetic Nanoparticles, Carbon nanotube.	ABSTRACT     Population growth, industrial development and technology transfer are among the factors of increasing water consumption and waste water production in communities and environmental pollution. Today, this pollution has become a big problem, which has made it necessary to invest in water treatment. Heavy metals are one of the most problematic and dangerous pollutants for the environment and humans. Mercury is considered as a global pollutant and a very toxic element due to its accumulation effect and high persistence in the environment. To remove toxic metals, the adsorbents that are easy and fast to separate and do not cause secondary pollution are preferred. In this study, a modified magnetic carbon nanotube has been prepared and used to remove mercury from polluted water. The physical, chemical and morphological characteristics of the adsorbent were determined with FT-IR and FE-SEM analyses. In the optimal conditions of pH=6, ambient temperature, 0.1 g of adsorbent, concentration of 10 ppm and time of 60 minutes, the adsorption efficiency was 96%.
How to cite this article Vahidi A., Eghtefari M., Tadayon F., Synthesis and Evaluation of the Effectiveness of Multi-component Magnetic/Carbon Nano Composite in Removing Heavy Metals from Aqueous Solutions. J. Nanoanalysis., 10 (2): 525-532, Spring 2023.

 

 

INTRODUCTION

Heavy metal pollution is a serious threat to human health and environmental systems [1]. Mercury ion is one of these metals that are known as very toxic elements [2]. Mercury exists in various forms, including elemental mercury (liquid), inorganic mercury (salts), and organic mercury (methylmercury) [3, 4]. Mercury damages the central nervous system, leads to kidney dysfunction and as a result chest pain and shortness of breath [2, 5]. This metal can be transferred through drinking water [2, 6], filling a tooth [7], and even through breast milk [7]. Different analytical techniques can be used to determine the effect of mercury [2]. Among these techniques, cold vapor atomic absorption spectrometry (CV-AAS) is the most widely used method for mercury determination [1]. Inductively coupled plasma mass spectrometry (ICP-MS) is useful in ultra-trace determination of total mercury without any pre-concentration step [8]. Since the concentration of mercury in environmental and biological samples is very low, its direct determination is difficult even with highly sensitive and selective analytical techniques. Therefore, a separation and preconcentration step is required before its determination [2, 6]. Nanocomposites are a revolutionary class of materials that are rapidly transforming various fields of engineering and science. These advanced materials are composed of at least two distinct phases: a matrix and a dispersed phase, where at least one dimension of the dispersed phase falls within the nanoscale range (typically 1-100 nanometers) [9, 10]. This unique nanoscale structure empowers nanocomposites with exceptional properties that often surpass those of their individual constituents [11, 12]. This enhanced interfacial interaction between the phases significantly influences the mechanical, electrical, thermal, and optical characteristics of the nanocomposite [11, 13]. By carefully engineering the composition, morphology, and interfacial interactions of these materials, scientists can tailor nanocomposites to fulfill a wide range of functional demands [14, 15]. Among these, carbon nanocomposites (CNCs) have garnered significant attention for their unique blend of characteristics inherited from various carbon nanomaterials, including carbon nanotubes (CNTs), graphene, and fullerenes [16, 17]. Magnetic nanocomposites represent a fascinating class of engineered materials that blend the unique properties of magnetic nanoparticles with those of a host matrix [18, 19]. The synergy between the magnetic nanoparticles and the host matrix is the cornerstone of magnetic nanocomposite functionality. The large surface area of the nanoparticles at the nanoscale fosters exceptional magnetic properties and facilitates interaction with external magnetic fields [20]. This magnetic responsiveness allows for remote manipulation of the nanocomposite, a capability that proves highly valuable in various applications [21]. The adsorption process is one of the most effective methods for removing heavy metals from aqueous solutions. Solid adsorbents can be easily used for pre-concentration and determination of metal ions in natural samples. Activated carbons of different origins are the main parts of these adsorbents [22].

 

EXPERIMENTAL

Materials and methods

All chemicals used were of analytical grade and were obtained from Merck. CNT with 95% purity, 2.1 g.cm-3 density, 200 m2.g specific surface area, and 30 μm particle length, Fourier transform infrared (FT-IR) spectrometer from Perkin-Elmer, Scanning electron microscope (SEM) from Philips, MIRA3 TESCAN-XMU field emission electron microscope (FE-SEM), Atomic absorption spectroscopy (AAS) with cold vapor technique using a Perkin-Elmer for mercury measurement, Kokusan centrifuge, Heidolph homogenizer, Binder oven, GFL 3005 mechanical stirrer, Mettler Ae 206 four-digit scale, Mettler Toledo pH meter and Bandeline Sonorex 12207D-Berlin ultrasonic cleaner was used.

Surface activation of carbon nanotubes

1g of CNT was poured into an Erlenmeyer flask. 67% concentrated nitric acid was slowly added to the Erlenmeyer. CNT completely formed a mixture in acid. This mixture was placed in an ultrasonic bath for 70 minutes and finally heated for 5 hours at a temperature range of 120 to 130°C. After cooling the mixture, centrifugation was performed at a speed of 6000 rpm for 15 minutes. The sediment was separated and washed until the pH of the solution reached 6. The mixture was filtered and the oxidized nanotubes were dried in an oven at 75°C for 20 hours.

Magnetic carbon nanotube (MNT) synthesis

300 ml of deionized water was poured into a three-hole flask. 43.4g FeCl3.6H2O (16mmol), 1.62g FeCl2.4H2O (8 mmol), 1.90g NiCl2.6H2O (8 mmol) and a magnet were added to the flask. The flask was kept under N2 gas for 30 minutes on a stirrer at a speed of 500 rpm at ambient temperature. 200 mg of oxidized CNT was added to 100 ml of deoxygenated water and placed in an ultrasonic bath for 20 minutes. Then it was added to the solution of metal salts. The flask was placed in a paraffin bath at a temperature of 80°C and the mixture was heated under nitrogen gas for 30 minutes. Then 40 ml of 25% ammonia was added dropwise to the mixture until the pH reached 11 and the brown precipitate turned black. The mixture was placed in ultrasonic and then the sample was stirred for 1 hour at 60°C with a mechanical stirrer. After cooling the mixture, the sample was washed until it reached neutral pH and dried in an oven at 50ºC for 10 hours. The nano adsorbent was placed in ultrasonic for 10 minutes.

Attachment of the functional groups to the synthesized MNT

Silica coating was prepared on MNT. 5 g of MNT was mixed with 200 ml of toluene. 5 ml of 3-chloropropyltrimethoxysilane (3-CPTS) and 0.5 ml of triethylamine were added to it. The mixture was refluxed for 48 hours. The precipitate was washed with ethanol and then with water and dried at 60°C for 8 hours. Then PF6 functional groups were attached on it.

Optimization of Parameters Affecting Mercury (II) Adsorption

The effect of pH, temperature and contact time, adsorbent dose and initial concentration on mercury (II) ion adsorption was investigated and the optimal amount of each factor was determined.

Investigation of Adsorbent Selectivity

To investigate the selectivity of the synthesized nano adsorbent for mercury(II) ions, 10 mg.L-1 solutions of sodium, calcium, copper, chromium, nickel, cadmium, and cobalt ions were prepared under the optimized conditions and removed using the same procedure as mercury. The results are shown in Table 1.

Desorption Studies

The synthesized nano adsorbent was washed with 8 mL of deionized water and separated by centrifugation at 3000 rpm for 10 minutes, then treated with 10 mL of 1 mol.L-1 nitric acid (HNO3), 10 mL of 1 mol.L-1 hydrochloric acid (HCl), 10 mL of 1% thiourea, 10 mL of 1% potassium thiocyanate (KSCN), 10 mL of 1 mol.L-1 potassium bromide (KBr) and 10 mL of 1 mol.L-1 diethyldithiocarbamate (DDTC) for 24 hours at 20 °C. The possibility of reusing the adsorbent after desorption process is shown in Table 2.

Application of MNT@SiO2-PF6 Nano adsorbent for Real Samples

1 g of a dry powdered sample of canned tuna produced in Iran was weighed and placed in a polyethylene container. A mixture of nitric acid and perchloric acid in a ratio of 3:1 was added to it. The container was closed and placed in a water bath at 100 °C. The heating process was continued until a clear yellow liquid was formed without any foreign objects or turbidity (3 hours). The resulting solution was brought to a volume of 10 mL using deionized water. At this stage, the Spiking technique was used.

 

Table 1. Selectivity of MNT@SiO2-PF6 Adsorbent for Mercury (II) Ions

Ion	Percentage Removal (%)
Mercury(II)	96.0
Sodium	35.8
Calcium	43.0
Copper	21.5
Chromium	24.7
Nickel	32.9
Cadmium	35.7
Cobalt	28.1

 

Table 2. Percentage Desorption of Mercury (II) Ions from 2MNT@SiO2-PF6 Adsorbent by Desorbing Agents

Desorbing Agents	Percentage Desorption of Mercury (II) (%)
KBr 1M	73.9
KSCN 1%	85.1
Thiourea  1%	93.8
DDTC 1M	91.4
HCl 1M	70.3
HNO3 1M	63.9

 

 

 

 

 

 

 

 

 

 

 

 

RESULTS AND DISCUSSION

Characterization of adsorbents

FT-IR analysis: Fig.1 shows the FT-IR spectra of functionalized carbon nanotubes (part a) and magnetic carbon nanotubes (part b). The peaks of 1644 cm-1 related to the carboxyl groups have shifted to the rational number of 1758 cm-1, which confirms the connection of nanoparticles to functional groups.  The peak related to the formation of oxidized iron nanoparticles is also observed at 584 cm-1. Fig.2 shows the FT-IR spectrum of the modified MNT@SiO2-PF6 nano adsorbent. In this figure, FT-IR spectral information shows that there is a strong interaction between MNT@SiO2 and PF6 ligand.

FE-SEM analysis: Fig.3 shows FE-SEM analysis for MNT@SiO2 composite (part b) and MNT@SiO2-PF6 composite (part a). MNT coated with silica has a size of 60 nm and due to being coated with silica; it is larger than carbon nanotubes whose size is reported to be 30 nm. The size of the final adsorbent nanoparticles is about 50 nanometers, and this decrease in size is due to the thinning of the silica coating when the PF6 ligand is added.

Optimization

The effect of pH: The percentage removal (%R) of mercury ion by MNT@SiO2-PF6 nano adsorbent at different pH is shown in Fig.4. The graph shows that the maximum amount of adsorption takes place at pH=6.

The effect of adsorbent dosage: Fig.5 shows the effect of the adsorbent dosage while other parameters are constant. According to this graph, the maximum amount of adsorption occurs in the dose of 0.1 g of nanoadsorbent.

 

 

Fig.1. FT-IR spectrum: (a): functionalized carbon nanotubes, (b): magnetized carbon nanotubes (MNT)

 

 

 

Fig.2. FT-IR spectrum of MNT@SiO2-PF6 adsorbent

 

Fig.3. FE-SEM analysis: (a): MNT@SiO2-PF6, (b): MNT@SiO2 composite

 

Fig.4. Effect of pH on Hg (II) adsorption efficiency by MNT@SiO2-PF6 adsorbent	Fig. 5. Effect of adsorbent dosage on mercury (II) adsorption efficiency

 

 

The effect of adsorbent dosage: Fig.5 shows the effect of the adsorbent dosage while other parameters are constant. According to this graph, the maximum amount of adsorption occurs in the dose of 0.1 g of nanoadsorbent.

The effect  of teperature and contact time:The percentage removal (%R) of mercury ion using nano adsorbent as a function of contact time at three different temperatures of 20, 40 and 60 °C is shown in Fig.6. As the graph shows, the maximum amount of adsorption takes place in 40 to 50 minutes and at a temperature of 20°C. Thus, the time of 40 minutes and the temperature of the laboratory environment were considered as the optimal conditions of temperature and contact time.

The effect of initial concentration of heavy metal: Fig.7 shows the percentage removal (%R) of mercury ion in different concentrations of this pollutant.The highest percentage of mercury removal by the adsorbent occurred at a concentration of 10 mg/L.

 

 

Fig.6. Effect of contact time at different temperatures on mercury adsorption efficiency	Fig.7. Effect of concentration of mercury (II) on adsorption efficiency

 

 

 

CONCLUSION

In this study, a magnetic carbon nanocomposite was synthesized, coated with silica and functionalized with 3-chloropropyltrimethoxysilane and imidazole-hexafluorophosphate groups. The synthesized adsorbent has suitable physical and chemical properties for the adsorption of mercury (II) ions from aqueous solutions. Adsorption parameters such as pH, temperature, adsorbent dosage and contact time were optimized and the adsorption efficiency was 96% under optimal conditions. The pH analysis showed that the adsorption process can have the highest rate in neutral environment and at ambient temperature, which indicates the possibility and speed of using nanocomposits in general applications.

 

REFERENCES

[1]        F. Tadayon, A. Katebi, A. Afkhami, Y. Panahi & H. Bagheri, A new potentiometric sensor based on a high-performance composite for nanomolar determination of mercury (II) in environmental samples, International Journal of Environmental Analytical Chemistry, 94(9), (2014), 901-915.

[2]        Sh. Motahar, M. Saber-tehrani, P. Aberoomand Azar and F. Tadayon, Preconcentration and separation of ultra-trace amounts of mercury(ii) using ultrasound-assisted cloud point-micro solid phase extraction based on modified silica aerogel with [1-(3,5-dicholorophenyl)-3(2-ethoxyphenyl)] triazene, J. Chil. Chem. Soc., 63(4), (2018).

[3]        Asoh, A. P., et al. (2023). The effects of mercury exposure on human health: A systematic review. Environmental Research, 120, 115120.

[4]        Liu, B., et al. (2024). Mercury in the environment: Sources, transport, fate, and effects. Science of the Total Environment, 914, 186836.

[5]        F. Tadayon, M. Saber-Tehrani and Sh. Motahar, Selective removal mercury (II) from aqueous solution using silica aerogel modified with AMTT, Korean J. Chem. Eng., 30(3), (2013), 642-648.

[6]        A. Abdollahi, M. Amirkavehei, M. M. Gheisari and F. Tadayon, Trace mercury determination in drinking and natural water after preconcentration and separation by DLLME-SFO method coupled with cold vapor atomic absorption spectrometry, 16th international conference on heavy metals in the environment, Rome, Italy, September 22–27, (2012).

[7]        A. Abdollahi, F. Tadayon and M. Amirkavei, Evaluation and determination of heavy metals (mercury, lead and cadmium) in human breast milk, 16th international conference on heavy metals in the environment, Rome, Italy, September 22–27, (2012).

[8]        F. Tadayon and Sh. Motahar, Preconcentration of mercury in human hair by modified silica aerogel nanoparticles, Academic Research International, 2(2), (2012).

[9]        Androutsi, E., & Mourkogiannis, T. (2023). Recent advances in covalently bonded ceramic/polymer nanocomposites. Progress in Materials Science, 138, 101072.

[10] Meng, Q., Liu, Z., Fu, S., & Zhu, Z. (2024). Interfacial design in 2D nanocomposites: A critical review. Chemical Society Reviews, 53, 1108-1142.

[11] Mohebpour, S., & Vahdat, S. M. (2023). Nanocomposites: A review. Materials Science and Engineering: R: Reports, 120, 1-25.

[12]        Shah, T. A., & Asif, H. M. (2023). Nanocomposites in the food packaging industry: A review. Critical Reviews in Food Science and Nutrition, 63 (18), 3322-3342.

[13]        Blazdell, L., & Petrova, T. (2024). Polymer nanocomposites for electromagnetic interference shielding. Nanotechnology Reviews, 13 (1), 1-20.

[14]        Zhu, J., Zhu, H., & Jia, D. (2023). Biopolymer nanocomposites for biomedical applications. Progress in Polymer Science, 135, 102025.

[15]        Geng, H., Zhao, S., Zhang, L., Cheng, Q., & Tang, Z. (2024). High-performance and multifunctional nanocomposites for structural health monitoring: A review. Sensors and Actuators, A: Physical, 390, 111588.

[16]        Chen, S., Zhu, W., Zhao, X., Xu, J., & Yang, H. (2023). High-performance and multifunctional graphene-based nanocomposites. Journal of Materials Science & Technology, 97, 17-43.

[17]        Chandrasekhar, A. V., Sreeprasad, T. S., & Gupta, N. (2024). Fullerenes and their derivatives as nanofillers in polymer nanocomposites. Progress in Polymer Science, 140, 101381.

[18]        Zhu, J., Zhu, H., & Jia, D. (2023). Biopolymer nanocomposites for biomedical applications. Progress in Polymer Science, 135, 102025.

[19]        Blazdell, L., & Petrova, T. (2024). Polymer nanocomposites for electromagnetic interference shielding. Nanotechnology Reviews, 13 (1), 1-20.

[20]        Liu, T., Li, L., Zhou, C., & Deng, Y. (2023). Functional magnetic nanocomposites for biomedical applications. Materials Today Bio, 18, 100400.

[21]        Kudrinski, E., Hernández-Vacheco, E., Muñoz-Espí, C., & Ruiz-García, J. (2023). Magnetic nanocomposites: Promising tools for hyperthermia cancer treatment. International Journal of Pharmaceutics, 656, 123823.

[22]        F. Tadayon, M. Hosseini and Sh. Motahar, Nanocomposite silica aerogel activated carbon: preparation, characterization and application to remove lead(II) from aqueous solutions, Journal of the Chinese Article Chemical Society, 59, (2012).

*Corresponding Author Email:  [e-mail]

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