(2024) Environmental Research_Establishment of circular economy by utilising textile industry waste as an adsorbent for textile dye removal

Kim J.Y.; Kim H.-B.; Kwon D.; Tsang Y.F.; Nam I.-H.; Kwon E.E.

(Academic Press Inc.) Environmental Research ISSN: 139351 Vol.262 Issue. Article No.119987 DOI: 10.1016/j.envres.2024.119987

This study explored the use of waste from the textile industry (silkworm byproducts) as a promising raw feedstock for the production of carbon-based adsorbents (biochar). The silk excreta biochar generated at 600 and 700 °C (referred to as SEB-600 and SEB-700, respectively) were evaluated in terms of their efficacy in adsorbing cationic (methylene blue) and anionic (Congo red) textile dyes. Although the functional groups on the surfaces of SEB-600 and SEB-700 were not significantly different, the specific surface area of SEB-700 was greater than that of SEB-600. The dye adsorption capacity of SEB-700 was higher than that of SEB-600. The adsorption of methylene blue and Congo red on SEB-700 followed Freundlich isotherms (R2 ≥ 0.963) and pseudo-second-order kinetics (R2 = 0.999), indicating chemisorption with multilayer characteristics. The mechanism for the adsorption of methylene blue on SEB-700 may involve interactions with the negatively charged functional groups on the surface and the mesopores of SEB-700. For the adsorption of Congo red, the mesopores in the biochar and the electrostatic interaction between biochar (positively charged because of the dye solution pH < pHzpc) and the anionic dye could affect adsorption. The maximum adsorption capacities of SEB-700 for methylene blue and Congo red were determined to be 168.23 and 185.32 mg g−1, respectively. Utilising the waste generated from the textile industry to remove pollutants will build a sustainable loop in the industry by minimising waste generation and pollutant emissions. © 2024

This work was supported by the Korea Environment Industry & Technology Institute (KEITI) through a project to Aquatic Ecosystem Conservation Research Program, funded by the Korea Ministry of Environment (MOE) (RS-2022-KE002133).