Polymer‐derived ceramic aerogels as sorbent materials for the removal of organic dyes from aqueous solutions

Abstract

Polymer‐derived SiC and SiOC aerogels have been synthesized and characterized both from the microstructural point of view and as sorbent materials for removing organic dyes (Methylene Blue, MB, and Rhodamine B, RB) from water solutions. Their adsorbent behavior has been compared with a polymer‐derived SiC foam and a commercial mesoporous silica. The aerogels can efficiently remove MB and RB from water solution and their capacity is higher compared to the SiC foams due to the higher surface area. The SiOC aerogel remains monolithic after the water treatment (allowing for an easy removal without the need of a filtration step) and its maximum capacity for removing MB is 42.2 mg/g, which is higher compared to the studied mesoporous silica and many C‐based porous adsorbents reported in the literature. The reason for this high adsorption capacity has been related to the unique structure of the polymer‐derived SiOC, which consists of an amorphous silicon oxycarbide network and a free carbon phase.

Polymer‐derived ceramic adsorbent for pollutant removal from water

“…However, it is still possible to extract information from silica‐based materials. Comparison done with high surface area (SSA of 757 m 2 /g) mesoporous silica having 113 mg/g capacity, with composite made of SiOC+wood (463.1 m 2 /g) having 173.5 mg/g capacity, and with SiOC aerogel (163 m 2 /g) having 42.2 mg/g capacity (all tested with MB) indicates that the both W and W‐HF showed consistent results with literature. Sample W having surface area of ~120 m 2 /g and W‐HF with ~660 m 2 /g resulted in the MB adsorption capacity of 49.3 mg/g and 104.3 mg/g, respectively.…”

“…While further studies required to reveal the observations related with FTIR data, it is known that the C=C and C‐N aromatic bonds associated with MB, RB, and CV appear in the range of 1000‐1600 cm −1 (see Figure A). 4 9‐51 As can be seen from Figure B while there are no peaks visible in the data for the sample W‐HF in such range, the sample after dye adsorption evidently demonstrates new bonds indicating that dyes were effectively loaded on the surface of the W‐HF sample …”

“…It is possible to state that the pronounced adsorption for dyes compared with that of metal ions can be attributed to Si‐OH bonds (available in SiOC and more in HF‐treated SiOC) and free carbon both of which may interact with the organic dyes through (a) Van der Waals forces between the dyes and the sp2 hybridized carbon, and (b) the electrostatic interaction between Si‐OH and/or the carbon‐oxygen complexes present.…”

“…[49][50][51] As can be seen from Figure 3B while there are no peaks visible in the data for the sample W-HF in such range, the sample after dye adsorption evidently demonstrates new bonds indicating that dyes were effectively loaded on the surface of the W-HF sample. 41 The micrographs show before (Figures 4A) and after ( Figure 4B-C-D) dye adsorption on W-HF. From the low magnification SEM image (see Figure S3(a)) irregular particles of around 200 lm can be seen.…”

Facile preparation of ultralight polymer‐derived SiOCN ceramic aerogels with hierarchical pore structure

“…It is seen that the properties of both FD and SD materials are comparable. However, SD technique requires rigorous experimental conditions to create supercritical state of CO 2 , extreme long time (~4 days) and complicated operation procedures. Therefore, compared to SD method, FD technique provides a low‐cost, timesaving (~16 hours), facile process and safe operation method to prepare polymer‐derived ceramic aerogels.…”