Micro/nanostructure and directional channel of recyclable carboxylated aerogels from waste cotton for wastewater treatment

• Published in: Cellulose (London) 2024-07, Vol.31 (10), p.6403-6419
• Main Authors: Gong, Shoujia, Zhang, Xiangyu, Chen, Shanwei, Ma, Yimeng, Mao, Zhiping, Ji, Bolin
• Format: Article
• Language: English
• Subjects: adsorbents; Adsorption; Aerogels; Bioorganic Chemistry; carboxylation; Cationic dyes; Cellulose; Ceramics; Chemistry; Chemistry and Materials Science; color; Composites; Cotton; Cutting speed; Dyeing; electrostatic interactions; Fabrics; freeze drying; Glass; High speed machining; Ion concentration; Methylene blue; nanomaterials; Nanostructure; Natural Materials; Organic Chemistry; Original Research; Oxidation; Physical Chemistry; Polymer Sciences; Recyclability; recycled water; Sustainable Development; value added; Waste utilization; wastewater; Wastewater treatment; Water reuse
• ISSN: 0969-0239; 1572-882X
• DOI: 10.1007/s10570-024-05957-y

Developing high value-added utilization of waste cotton provides a promising approach for the sustainable development. Herein, the carboxylated cellulose aerogels (CCAs) featuring in micro/nanostructure and directional channel are fabricated from cotton fabrics via the ingenious combination of selective oxidation, high-speed cutting, and freeze-drying. The as-prepared 2.0-CCA demonstrates not only excellent adsorption capacity for cationic dyes in water but also recyclability due to the abundant carboxyl groups (3.20 mmol/g) and the robust porous structure. And it shows a static maximum adsorption capacity (q m ) of 751 mg/g and a dynamic breakthrough amount more than 700 mg/g for methylene blue (MB), more efficient than most reported cellulose-based adsorbents. In addition, the 2.0-CCA shows a high equilibrium adsorption capacity (q e ) about 680 mg/g for MB at pH = 6 and keeps q e above 600 mg/g even in a broad pH range of 3‒10, indicating a high tolerance to the solution pH value. At an ion concentration lower than 0.25 mol/L, the additional cations such as Na + and K + or anions such as Cl ‒ , SO 4 2‒ , and NO 3 ‒ show a little effect on the q e (higher than 500 mg/g) of 2.0-CCA for MB. The treated dye wastewater can be recycled for fabric dyeing, and there is no significant color difference (∆E) between fabrics dyed with dye liquors prepared with fresh or recycled water. The theoretical study confirms the importance of the electrostatic attraction between carboxyl groups of 2.0-CCA and dye molecules for the efficient adsorption.