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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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(a) Powder XRD patterns of the Si–C–N porous materials obtained from P3 (PSZ:PDVB:NiCp2  = 1:1:4) at 600, 750, and 1100°C, (b) Raman spectrum of Si–C–N porous materials obtained from P1 (PSZ:PDVB:NiCp2 = :2:0.04) pyrolyzed at 600°C.
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f5: (a) Powder XRD patterns of the Si–C–N porous materials obtained from P3 (PSZ:PDVB:NiCp2 = 1:1:4) at 600, 750, and 1100°C, (b) Raman spectrum of Si–C–N porous materials obtained from P1 (PSZ:PDVB:NiCp2 = :2:0.04) pyrolyzed at 600°C.

Mentions: The powder XRD patterns for porous hybrid materials (PSZ:PDVB:NiCp2 = 1:1:0.04) pyrolyzed at different temperature are displayed in Figure 5a. Pyrolysis at low temperature (600 and 750°C) leads to materials with complete amorphous structures. When the pyrolysis temperature is increased to 1,100°C, distinct crystalline peak is still not observed, indicating the good structural stability of porous Si–C–N materials. The broad diffraction peak at 2θ = 26° indicates the presence of numerous free carbons derived from the residues of PDVB and PSZ. A main feature of PDCs is the possibility to incorporate free carbon into the matrix, which is favorable for the structural stability against crystallization and high-temperature resistance to oxidation37. For example, Mera et al.38 reported that the crystallization depended on the carbon content for different precursors, and the sample with the highest carbon content was less likely to form the β-SiC phase. Herein, it could be concluded that although the incorporation of Ni was helpful for the formation of crystalline phase, the presence of carbon could render the amorphous characteristic at higher temperatures39. Besides, the addition of nickel could catalyze the formation of conjugated carbons (C = C, sp2) similar to polyaromatic-like conjugated structure3640, which might be helpful for the interaction between the porous Si–C–N material and the organic dyes.


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)

(a) Powder XRD patterns of the Si–C–N porous materials obtained from P3 (PSZ:PDVB:NiCp2  = 1:1:4) at 600, 750, and 1100°C, (b) Raman spectrum of Si–C–N porous materials obtained from P1 (PSZ:PDVB:NiCp2 = :2:0.04) pyrolyzed at 600°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: (a) Powder XRD patterns of the Si–C–N porous materials obtained from P3 (PSZ:PDVB:NiCp2 = 1:1:4) at 600, 750, and 1100°C, (b) Raman spectrum of Si–C–N porous materials obtained from P1 (PSZ:PDVB:NiCp2 = :2:0.04) pyrolyzed at 600°C.
Mentions: The powder XRD patterns for porous hybrid materials (PSZ:PDVB:NiCp2 = 1:1:0.04) pyrolyzed at different temperature are displayed in Figure 5a. Pyrolysis at low temperature (600 and 750°C) leads to materials with complete amorphous structures. When the pyrolysis temperature is increased to 1,100°C, distinct crystalline peak is still not observed, indicating the good structural stability of porous Si–C–N materials. The broad diffraction peak at 2θ = 26° indicates the presence of numerous free carbons derived from the residues of PDVB and PSZ. A main feature of PDCs is the possibility to incorporate free carbon into the matrix, which is favorable for the structural stability against crystallization and high-temperature resistance to oxidation37. For example, Mera et al.38 reported that the crystallization depended on the carbon content for different precursors, and the sample with the highest carbon content was less likely to form the β-SiC phase. Herein, it could be concluded that although the incorporation of Ni was helpful for the formation of crystalline phase, the presence of carbon could render the amorphous characteristic at higher temperatures39. Besides, the addition of nickel could catalyze the formation of conjugated carbons (C = C, sp2) similar to polyaromatic-like conjugated structure3640, which might be helpful for the interaction between the porous Si–C–N material and the organic dyes.

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