Facile synthesis of carbon nitride-doped cellulose aerogels with high selective adsorption of cationic dyes from wastewater

Printing and dyeing wastewater, characterized by its complex composition, posing hazards to both the environment and human health. Traditional adsorption and removal methods face challenges in achieving mixed dye separation while being prone to causing secondary pollution. This study delves into the selective adsorption of complex printing and dyeing wastewater using cellulose-derived aerogels through structural design, chemical modification, and selective adsorption performance. Three-dimensional porous carbon nitride-doped cellulose aerogels (CE/CN) were successfully prepared by chemically crosslinking KOH-etched carbon nitride CN) into cellulose aerogels followed by freeze-drying. Excellent thermochemical stability and selectivity to cationic dyes was achieved by doping CE/CN with CN. The aerogel exhibits a 99.07 % selective removal efficiency for cationic dye methylene blue (MB) in mixed dye solutions, with a maximum adsorption capacity of 212.105 mg/g for MB dye. Compared with other types of adsorbents, the uniqueness of aerogel lies in its ability to regenerate under strong alkaline conditions while consistently demonstrating exceptional adsorption performance over six cycles. These findings not only offer an effective theoretical basis and technical support for selectively removing cationic dyes from printing and dyeing wastewater but also hold significant implications for the application of cellulose-based composites in environmental fields.