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On-line micro column preconcentration system based on amino bimodal mesoporous silica nanoparticles as a novel adsorbent for removal and speciation of chromium (III, VI) in environmental samples.

Shirkhanloo H, Khaligh A, Golbabaei F, Sadeghi Z, Vahid A, Rashidi A - J Environ Health Sci Eng (2015)

Bottom Line: TEM, XRD, and SEM results confirmed the beneficial properties of NH2-UVM-7 as the adsorbent for chromium extraction.The efficiency of nanoadsorbent for preconcentration and extraction of Cr (VI) was 96 %, whereas it was less than 5 % for Cr (III).Good recoveries, with low detection limits and good preconcentration factors are the main advantages of this procedure.

View Article: PubMed Central - PubMed

Affiliation: Occupational and Environmental Health Research Center (OEHRC), Iranian Petroleum Industry Health Research Institute (IPIHRI-PIHO), Tehran, 1485733111 Iran ; Research Institute of Petroleum Industry (RIPI), Tehran, 14665-1137 Iran.

ABSTRACT

Background: Chromium (VI) has toxic and carcinogenic effects. So, determination and speciation of chromium in environmental samples is very important in view of health hazards. In this study, solid phase extraction (SPE) based on bulky amine-functionalized bimodal mesoporous silica nanoparticles (NH2-UVM-7) as a novel nanoadsorbent was applied for preconcentration and speciation of chromium (III, VI) in water samples.

Methods: UVM-7 was synthesized via atrane route and subsequently functionalized with amino silane via grafting method. In SPE procedure, polymer tubing as a micro-column was filled with NH2-UVM-7 adsorbent. Preconcentration and speciation of Cr (III) and Cr (VI) ions with NH2-UVM-7 were obtained in water samples due to the fact that only Cr (VI) ions can be complexed with-NH2 groups at optimized pH. Finally, chromium concentration was determined by flame atomic absorption spectrometry (F-AAS).

Results: TEM, XRD, and SEM results confirmed the beneficial properties of NH2-UVM-7 as the adsorbent for chromium extraction. Under the optimal conditions, linear calibration curve, detection limit and preconcentration factor were obtained 6-320 μg/ L, 1.2 μg/L and 66.7, respectively (RSD < 5 %). The efficiency of nanoadsorbent for preconcentration and extraction of Cr (VI) was 96 %, whereas it was less than 5 % for Cr (III).

Conclusions: The developed NH2-UVM7-based SPE/F-AAS method has enough sensitively and simplicity for speciation and determination of Cr (VI) and Cr (III) ions in real water samples. Good recoveries, with low detection limits and good preconcentration factors are the main advantages of this procedure.

No MeSH data available.


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Langmuir plot for chromium adsorption by NH2-UVM-7 at different temperatures
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Fig9: Langmuir plot for chromium adsorption by NH2-UVM-7 at different temperatures

Mentions: Where Ce is the equilibrium concentration of metal ions in solution phase (mg/L) and qe is the amount of metal ions adsorbed at equilibrium (mg/g), Qmax is maximum adsorption capacity (mg/g) on unit mass of adsorbent, and b is the Langmuir constant (L/mg), related to the free energy of adsorption. The Langmuir model provided a good fit throughout the concentration range. The applicability of the isotherm models and the high values of the correlation coefficients (R2 = 0.9958) for Cr (VI) suggest favourable adsorption by NH2-UVM7 at 45 °C. The value of Qmax in Langmuir plots was 192 mg/g for Cr (VI) ions at 45 °C. The values of Qmax and effective time for flow rate are depended on temperature of solution. According to the results, the maximum capacity of adsorbent in column condition due to the shorter contact time is 5 % less than batch system, which is apparently quite expected. The Langmuir isotherm plots at different temperatures and the value of model constants were shown in Fig. 9 and Table 7, respectively.Fig. 9


On-line micro column preconcentration system based on amino bimodal mesoporous silica nanoparticles as a novel adsorbent for removal and speciation of chromium (III, VI) in environmental samples.

Shirkhanloo H, Khaligh A, Golbabaei F, Sadeghi Z, Vahid A, Rashidi A - J Environ Health Sci Eng (2015)

Langmuir plot for chromium adsorption by NH2-UVM-7 at different temperatures
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4940767&req=5

Fig9: Langmuir plot for chromium adsorption by NH2-UVM-7 at different temperatures
Mentions: Where Ce is the equilibrium concentration of metal ions in solution phase (mg/L) and qe is the amount of metal ions adsorbed at equilibrium (mg/g), Qmax is maximum adsorption capacity (mg/g) on unit mass of adsorbent, and b is the Langmuir constant (L/mg), related to the free energy of adsorption. The Langmuir model provided a good fit throughout the concentration range. The applicability of the isotherm models and the high values of the correlation coefficients (R2 = 0.9958) for Cr (VI) suggest favourable adsorption by NH2-UVM7 at 45 °C. The value of Qmax in Langmuir plots was 192 mg/g for Cr (VI) ions at 45 °C. The values of Qmax and effective time for flow rate are depended on temperature of solution. According to the results, the maximum capacity of adsorbent in column condition due to the shorter contact time is 5 % less than batch system, which is apparently quite expected. The Langmuir isotherm plots at different temperatures and the value of model constants were shown in Fig. 9 and Table 7, respectively.Fig. 9

Bottom Line: TEM, XRD, and SEM results confirmed the beneficial properties of NH2-UVM-7 as the adsorbent for chromium extraction.The efficiency of nanoadsorbent for preconcentration and extraction of Cr (VI) was 96 %, whereas it was less than 5 % for Cr (III).Good recoveries, with low detection limits and good preconcentration factors are the main advantages of this procedure.

View Article: PubMed Central - PubMed

Affiliation: Occupational and Environmental Health Research Center (OEHRC), Iranian Petroleum Industry Health Research Institute (IPIHRI-PIHO), Tehran, 1485733111 Iran ; Research Institute of Petroleum Industry (RIPI), Tehran, 14665-1137 Iran.

ABSTRACT

Background: Chromium (VI) has toxic and carcinogenic effects. So, determination and speciation of chromium in environmental samples is very important in view of health hazards. In this study, solid phase extraction (SPE) based on bulky amine-functionalized bimodal mesoporous silica nanoparticles (NH2-UVM-7) as a novel nanoadsorbent was applied for preconcentration and speciation of chromium (III, VI) in water samples.

Methods: UVM-7 was synthesized via atrane route and subsequently functionalized with amino silane via grafting method. In SPE procedure, polymer tubing as a micro-column was filled with NH2-UVM-7 adsorbent. Preconcentration and speciation of Cr (III) and Cr (VI) ions with NH2-UVM-7 were obtained in water samples due to the fact that only Cr (VI) ions can be complexed with-NH2 groups at optimized pH. Finally, chromium concentration was determined by flame atomic absorption spectrometry (F-AAS).

Results: TEM, XRD, and SEM results confirmed the beneficial properties of NH2-UVM-7 as the adsorbent for chromium extraction. Under the optimal conditions, linear calibration curve, detection limit and preconcentration factor were obtained 6-320 μg/ L, 1.2 μg/L and 66.7, respectively (RSD < 5 %). The efficiency of nanoadsorbent for preconcentration and extraction of Cr (VI) was 96 %, whereas it was less than 5 % for Cr (III).

Conclusions: The developed NH2-UVM7-based SPE/F-AAS method has enough sensitively and simplicity for speciation and determination of Cr (VI) and Cr (III) ions in real water samples. Good recoveries, with low detection limits and good preconcentration factors are the main advantages of this procedure.

No MeSH data available.


Related in: MedlinePlus