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Hierarchically porous silicon-carbon-nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes.

Meng L, Zhang X, Tang Y, Su K, Kong J - Sci Rep (2015)

Bottom Line: The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates.On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red.Thus, the hierarchically porous Si-C-N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants.

View Article: PubMed Central - PubMed

Affiliation: MOE Key Laboratory of Space Applied Physics and Chemistry, Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi'an, 710072, P. R. China.

ABSTRACT
The hierarchically macro/micro-porous silicon-carbon-nitrogen (Si-C-N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg·g(-1) and 1084.5 mg·g(-1) for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si-C-N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants.

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Plots of Ln(Qe/Ce) vs. Qe for the calculation of thermodynamic parameters.
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f13: Plots of Ln(Qe/Ce) vs. Qe for the calculation of thermodynamic parameters.

Mentions: where as is the activity of adsorbed dye, ae is the activity of dye in solution at equilibrium, Qe is the amount of dye adsorbed by per unit mass of adsorbent (mg·g−1), vs is the activity coefficient of the adsorbed dye, and ve is the activity coefficient of dye in solution. The concentration of dye in the solution decreases and reaches zero; therefore, K0 can be obtained by plotting Ln(Qe/Ce) vs. Qe and extrapolating Qe to zero, as shown in Figure 13. The value of R2 obtained from a linear regression analysis is 0.90267 and 0.86085 for MB and AF, respectively. The value of K0 from the straight line intercept with the vertical axis is 6.09 for MB and 5.32 for AF. Accordingly, the ΔG0 values are −4.48 kJ·mol−1 for MB and −4.14 kJ·mol−1 for AF. It confirms that the adsorption of dyes onto C1 is spontaneous and thermodynamically favorable.


Hierarchically porous silicon-carbon-nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes.

Meng L, Zhang X, Tang Y, Su K, Kong J - Sci Rep (2015)

Plots of Ln(Qe/Ce) vs. Qe for the calculation of thermodynamic parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4300473&req=5

f13: Plots of Ln(Qe/Ce) vs. Qe for the calculation of thermodynamic parameters.
Mentions: where as is the activity of adsorbed dye, ae is the activity of dye in solution at equilibrium, Qe is the amount of dye adsorbed by per unit mass of adsorbent (mg·g−1), vs is the activity coefficient of the adsorbed dye, and ve is the activity coefficient of dye in solution. The concentration of dye in the solution decreases and reaches zero; therefore, K0 can be obtained by plotting Ln(Qe/Ce) vs. Qe and extrapolating Qe to zero, as shown in Figure 13. The value of R2 obtained from a linear regression analysis is 0.90267 and 0.86085 for MB and AF, respectively. The value of K0 from the straight line intercept with the vertical axis is 6.09 for MB and 5.32 for AF. Accordingly, the ΔG0 values are −4.48 kJ·mol−1 for MB and −4.14 kJ·mol−1 for AF. It confirms that the adsorption of dyes onto C1 is spontaneous and thermodynamically favorable.

Bottom Line: The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates.On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red.Thus, the hierarchically porous Si-C-N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants.

View Article: PubMed Central - PubMed

Affiliation: MOE Key Laboratory of Space Applied Physics and Chemistry, Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi'an, 710072, P. R. China.

ABSTRACT
The hierarchically macro/micro-porous silicon-carbon-nitrogen (Si-C-N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg·g(-1) and 1084.5 mg·g(-1) for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si-C-N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants.

Show MeSH