Limits...
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.

Show MeSH
Removal percentages of MB in five recycle runs using regenerated C1 (initial concentration: 200 mg·L−1).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4300473&req=5

f16: Removal percentages of MB in five recycle runs using regenerated C1 (initial concentration: 200 mg·L−1).

Mentions: The selective adsorption experiments were performed on several other dyes with different molecular structures as presented in Figure 14 and Figure 15. The results exhibit that the porous Si–C–N hybrid material also shows totally selective adsorption property, i.e. high adsorption capacity for MG, MV and BF and no adsorption for MO, MR and CR. It seems to be that all dyes with bulky triphenyl structure can be absorbed by C1, however, the dyes with azo benzene (MO, MR, CR) cannot be absorbed. The repeatability is also important for an adsorbent for its feasible and practical application. The hybrid material could be easily regenerated by sintering because of its resistance to high temperature. In this study, MB was used as the model dye to investigate the recyclability of porous Si–C–N hybrid material. Figure 16 shows the removal percentages of MB in five recycle runs using regenerated C1. It was observed that the removal efficiency was 96.94 and 96.11% in the first two runs and decreased slightly to 94.33% and 93.56% in the fourth and fifth runs, respectively. The good repeatability was attributed to the stability of sp2 hybridized carbons as well as good structural stability of amorphous Si-C-N framework at the temperature below 600°C, which ensured enough adsorption sites for five recycling process to treat the low concentration dye solution (C0 = 200 mg·L−1). Moreover, Figure S6 shows the XPS analysis performed on the sample C1 recycled after five runs (C1-five). Compared to the original C1, the surface elemental composition of C1-five underwent some modifications. The results of the calculations revealed that the relative content of silicon and nitrogen decreased, however the relative content of carbon and oxygen increased dramatically compared to the composition of C1. However, the adsorption efficiency did not change significantly, indicating the good adsorption properties. Therefore, it was expected that this material was promising in the practical application of adsorption of dyes from wastewater.


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)

Removal percentages of MB in five recycle runs using regenerated C1 (initial concentration: 200 mg·L−1).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f16: Removal percentages of MB in five recycle runs using regenerated C1 (initial concentration: 200 mg·L−1).
Mentions: The selective adsorption experiments were performed on several other dyes with different molecular structures as presented in Figure 14 and Figure 15. The results exhibit that the porous Si–C–N hybrid material also shows totally selective adsorption property, i.e. high adsorption capacity for MG, MV and BF and no adsorption for MO, MR and CR. It seems to be that all dyes with bulky triphenyl structure can be absorbed by C1, however, the dyes with azo benzene (MO, MR, CR) cannot be absorbed. The repeatability is also important for an adsorbent for its feasible and practical application. The hybrid material could be easily regenerated by sintering because of its resistance to high temperature. In this study, MB was used as the model dye to investigate the recyclability of porous Si–C–N hybrid material. Figure 16 shows the removal percentages of MB in five recycle runs using regenerated C1. It was observed that the removal efficiency was 96.94 and 96.11% in the first two runs and decreased slightly to 94.33% and 93.56% in the fourth and fifth runs, respectively. The good repeatability was attributed to the stability of sp2 hybridized carbons as well as good structural stability of amorphous Si-C-N framework at the temperature below 600°C, which ensured enough adsorption sites for five recycling process to treat the low concentration dye solution (C0 = 200 mg·L−1). Moreover, Figure S6 shows the XPS analysis performed on the sample C1 recycled after five runs (C1-five). Compared to the original C1, the surface elemental composition of C1-five underwent some modifications. The results of the calculations revealed that the relative content of silicon and nitrogen decreased, however the relative content of carbon and oxygen increased dramatically compared to the composition of C1. However, the adsorption efficiency did not change significantly, indicating the good adsorption properties. Therefore, it was expected that this material was promising in the practical application of adsorption of dyes from wastewater.

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