Study of photocatalytic degradation of dyeing wastewater with CdS nanoparticles anchored on cotton short staple-based carbon aerogels

The photocatalytic technology is widely recognized as an effective solution for both the energy crisis and environmental issues. Developing cost-effective alternatives to noble metal-based photocatalytic catalysts is crucial for the degradation of organic pollutants in dye wastewater; however, it remains a challenging task. In this study, a novel approach was presented, wherein a cotton-based carbon aerogel was synthesized using short staple cotton cellulose as the raw material. CdS nanoparticles were then anchored onto the three-dimensional porous structure of the carbon aerogel. The resulting materials were thoroughly characterized and analyzed using various techniques, including XRD, SEM, Mapping, XPS, BET, and UV-Vis spectroscopy, and their performance was extensively assessed. Experimental results indicated that the degradation efficiency of 20 ml (15 mg/L) methylene blue solution reached 95.7 % within 90 min, achieving near-complete degradation within 120 min using 10 mg catalyst material. Furthermore, photocatalytic degradation experiments were conducted on commonly used reactive red dye (K-type) and reactive yellow dye (M-type) that are typically employed in textile dyeing and finishing processes. For 20 ml of waste liquid, after 90 min, the degradation rates of the reactive red and yellow dyes reached 91.4 % and 94.4 %, respectively, with complete degradation achieved within 120 min. Free radical quenching experiments demonstrated that hydroxyl radicals (•OH) and superoxide radicals (•O 2 - ) played a central role in mediating the photocatalytic degradation of organic pollutants using the CdS/carbon aerogel (CdS/CA) composite material. Overall, the research findings suggest that the CdS/CA composite material exhibited highly desirable attributes, effectively adsorbing and photodegrading methylene blue as well as organic dyes in dye wastewater. These results provide valuable insights for the development of cost-effective photocatalytic materials and the efficient degradation of dyes. • The composite carbon aerogel has a very high specific surface area. • The aerogel, as a carrier, can protect the photocatalyst nanoparticles from aggregating or deactivating during the photocatalytic reaction. • The composite carbon aerogel has the following advantages compared to the single CdS nanoparticles, it can promote the effective separation of photogenerated electrons and holes.