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Significantly enhanced dye removal performance of hollow tin oxide nanoparticles via carbon coating in dark environment and study of its mechanism.

Yang S, Wu Z, Huang L, Zhou B, Lei M, Sun L, Tian Q, Pan J, Wu W, Zhang H - Nanoscale Res Lett (2014)

Bottom Line: The resulting products were characterized in terms of morphology, composition, and surface property by various analytical techniques.Moreover, the SnO2@C hollow nanoparticles are shown to be effective adsorbents for removing four different dyes from aqueous solutions, which is superior to the pure hollow SnO2 nanoparticles and commercial SnO2.The enhanced mechanism has also been discussed, which can be attributed to the high specific surface areas after carbon coating.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, People's Republic of China ; Laboratory of Printable Functional Nanomaterials and Printed Electronics, School of Printing and Packaging, Wuhan University, Wuhan 430072, People's Republic of China.

ABSTRACT
Understanding the correlation between physicochemical properties and morphology of nanostructures is a prerequisite for widespread applications of nanomaterials in environmental application areas. Herein, we illustrated that the uniform-sized SnO2@C hollow nanoparticles were large-scale synthesized by a facile hydrothermal method. The size of the core-shell hollow nanoparticles was about 56 nm, and the shell was composed of a solid carbon layer with a thickness of 2 ~ 3 nm. The resulting products were characterized in terms of morphology, composition, and surface property by various analytical techniques. Moreover, the SnO2@C hollow nanoparticles are shown to be effective adsorbents for removing four different dyes from aqueous solutions, which is superior to the pure hollow SnO2 nanoparticles and commercial SnO2. The enhanced mechanism has also been discussed, which can be attributed to the high specific surface areas after carbon coating.

No MeSH data available.


Nitrogen adsorption-desorption isotherms and pore size distribution. (a) Nitrogen adsorption-desorption isotherms of the as-synthesized SnO2 and hollow SnO2@C nanoparticles. (b) The pore size distribution of the hollow SnO2@C nanoparticles.
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Figure 7: Nitrogen adsorption-desorption isotherms and pore size distribution. (a) Nitrogen adsorption-desorption isotherms of the as-synthesized SnO2 and hollow SnO2@C nanoparticles. (b) The pore size distribution of the hollow SnO2@C nanoparticles.

Mentions: To avoid the photocatalytic effect of SnO2 and SnO2@C nanoparticles, the dye removal tests are carried out in a dark environment. And the results reveal that the carbon coating can enhance the absorption abilities. To illustrate the reason, the nitrogen adsorption isotherms of the hollow SnO2 and SnO2@C nanoparticles have been measured and shown in Figure 7. The BET surface areas of the hollow SnO2 and SnO2@C nanoparticles are 60.59 and 168.33 m2/g, respectively. Both samples exhibit the type IV isotherms with a distinct hysteresis loop at the relative pressure P/P0 ranging from 0.5 to 0.8. Clearly, the carbon coating will greatly enhance the surface area, which can be the main reason of significant enhanced dye removal performance of hollow SnO2@C nanoparticles. The large number and array of different functional groups on the carbon layers (e.g., carboxylic, hydroxyl, carbonyl) implied the existence of many types of adsorbent-solute interaction [22]. Additionally, carbon coating has made the covalent bond interaction with hexagonal structure, which has a -π structure properties of aromatic ring, easy to interact with conjugated double bonds. And some of the dye structure have conjugated double bonds and easy to be adsorbed by the coating carbon [23]. As shown in Figure 8, the hollow SnO2@C nanoparticles can capture more dye molecules due to the introduced carbon layer. Indeed, relatively larger amount of water and hydroxyl groups can be adsorbed on the surface by hydrothermal process [24]. The surface chemistry of the adsorbents plays a major role in the adsorption. The adsorption of the reactive dye on carbon is favored, mainly due to the dispersive interactions between the delocalized π electrons of the carbon materials and the free electrons of the dye molecules [20]. The functional groups on the hollow SnO2@C nanoparticles' surface acted as a negative potential that provides a weak electrostatic interaction between the organic dyes and the hollow SnO2@C nanoparticles.


Significantly enhanced dye removal performance of hollow tin oxide nanoparticles via carbon coating in dark environment and study of its mechanism.

Yang S, Wu Z, Huang L, Zhou B, Lei M, Sun L, Tian Q, Pan J, Wu W, Zhang H - Nanoscale Res Lett (2014)

Nitrogen adsorption-desorption isotherms and pore size distribution. (a) Nitrogen adsorption-desorption isotherms of the as-synthesized SnO2 and hollow SnO2@C nanoparticles. (b) The pore size distribution of the hollow SnO2@C nanoparticles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4150862&req=5

Figure 7: Nitrogen adsorption-desorption isotherms and pore size distribution. (a) Nitrogen adsorption-desorption isotherms of the as-synthesized SnO2 and hollow SnO2@C nanoparticles. (b) The pore size distribution of the hollow SnO2@C nanoparticles.
Mentions: To avoid the photocatalytic effect of SnO2 and SnO2@C nanoparticles, the dye removal tests are carried out in a dark environment. And the results reveal that the carbon coating can enhance the absorption abilities. To illustrate the reason, the nitrogen adsorption isotherms of the hollow SnO2 and SnO2@C nanoparticles have been measured and shown in Figure 7. The BET surface areas of the hollow SnO2 and SnO2@C nanoparticles are 60.59 and 168.33 m2/g, respectively. Both samples exhibit the type IV isotherms with a distinct hysteresis loop at the relative pressure P/P0 ranging from 0.5 to 0.8. Clearly, the carbon coating will greatly enhance the surface area, which can be the main reason of significant enhanced dye removal performance of hollow SnO2@C nanoparticles. The large number and array of different functional groups on the carbon layers (e.g., carboxylic, hydroxyl, carbonyl) implied the existence of many types of adsorbent-solute interaction [22]. Additionally, carbon coating has made the covalent bond interaction with hexagonal structure, which has a -π structure properties of aromatic ring, easy to interact with conjugated double bonds. And some of the dye structure have conjugated double bonds and easy to be adsorbed by the coating carbon [23]. As shown in Figure 8, the hollow SnO2@C nanoparticles can capture more dye molecules due to the introduced carbon layer. Indeed, relatively larger amount of water and hydroxyl groups can be adsorbed on the surface by hydrothermal process [24]. The surface chemistry of the adsorbents plays a major role in the adsorption. The adsorption of the reactive dye on carbon is favored, mainly due to the dispersive interactions between the delocalized π electrons of the carbon materials and the free electrons of the dye molecules [20]. The functional groups on the hollow SnO2@C nanoparticles' surface acted as a negative potential that provides a weak electrostatic interaction between the organic dyes and the hollow SnO2@C nanoparticles.

Bottom Line: The resulting products were characterized in terms of morphology, composition, and surface property by various analytical techniques.Moreover, the SnO2@C hollow nanoparticles are shown to be effective adsorbents for removing four different dyes from aqueous solutions, which is superior to the pure hollow SnO2 nanoparticles and commercial SnO2.The enhanced mechanism has also been discussed, which can be attributed to the high specific surface areas after carbon coating.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, People's Republic of China ; Laboratory of Printable Functional Nanomaterials and Printed Electronics, School of Printing and Packaging, Wuhan University, Wuhan 430072, People's Republic of China.

ABSTRACT
Understanding the correlation between physicochemical properties and morphology of nanostructures is a prerequisite for widespread applications of nanomaterials in environmental application areas. Herein, we illustrated that the uniform-sized SnO2@C hollow nanoparticles were large-scale synthesized by a facile hydrothermal method. The size of the core-shell hollow nanoparticles was about 56 nm, and the shell was composed of a solid carbon layer with a thickness of 2 ~ 3 nm. The resulting products were characterized in terms of morphology, composition, and surface property by various analytical techniques. Moreover, the SnO2@C hollow nanoparticles are shown to be effective adsorbents for removing four different dyes from aqueous solutions, which is superior to the pure hollow SnO2 nanoparticles and commercial SnO2. The enhanced mechanism has also been discussed, which can be attributed to the high specific surface areas after carbon coating.

No MeSH data available.