关键词: 灯心草, 活性炭, 印染废水, 罗丹明B, 染料吸附, 多孔材料, 生物质材料

Abstract:

Objective Addressing the detrimental impact of textile printing and dyeing wastewater is crucial for the sustainable development of the textile industry and essential for mitigating the damage to water ecosystems, advancing ecological protection, and promoting the sustainable use of water resources. Adsorption technology, owing to its simplicity, flexibility, and efficiency in water purification, offers a promising solution to this issue. However, the powdered form of activated carbon - an effective dye adsorbent - poses challenges in both practical applications and disposal following dye adsorption.

Method Herein, activated carbon-Juncus effusus (AC-JE), a natural cellulose-based adsorbent, was employed for the treatment of dyeing and printing wastewater. Juncus effusus was immersed in a dilute alkaline solution to enhance its hydrophilicity, followed by immersion in an activated carbon dispersion to uniformly load the activated carbon and obtain AC-JE. The adsorption effects were evaluated under varying conditions utilizing rhodamine B as the dye model. Micromorphology, absorption properties, thermal stability properties, and pore structure were analyzed. The adsorption effect was investigated for different AC-JE masses, adsorption times, and initial Rhodamine B solution concentrations.

Results The results indicated that the dye adsorption removal rate increased as the adsorbent input increased. After determining the mass of the adsorbent, the adsorption sites gradually became saturated as the adsorption time increased, and the adsorption capacity increased until equilibrium was reached. This 50 mg mass of AC-JE was used to adsorb 20 mg/L of Rhodamine B stain, and saturation of adsorption was reached after 60 min. The adsorption involved an initial binding of the dye to the adsorption sites of the activated carbon, followed by adsorption of the dye onto the available adsorption sites of Juncus effusus until all the cavities in both the activated carbon and macropores of Juncus effusus were filled. This 100 mg mass of AC-JE was used to filter 20 mL of Rhodamine B stain and can continue to be used to filter the next stain. After five filtration cycles, the dye removal rate was 99.06%, and after seven filtraction cycles, the removal rate remained at 85.57%.

Conclusion The AC-JE composite fiber combines the macroporous structure of Juncus effusus with the microporous and mesoporous structures of activated carbon, thereby providing additional adsorption sites and increasing the contact area between the adsorbent and dye molecules. This material provides a reliable solution for wastewater treatment. The adsorption of Rhodamine B by Juncus effusus reached saturation at 3.37 mg/g, whereas the adsorption capacity of AC-JE remained stable at 3.99 mg/g, with a removal rate of 99.97%. The adsorption process followed a pseudo-second-order kinetic equation and the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 142.43 mg/g. The dye removal rate was 85.57% even after seven filtration cycles, validating its recyclability and efficiency. As a natural cellulose-based adsorbent, AC-JE holds significant potential for widespread applications in industrial wastewater treatment, providing valuable insights for the development of more efficient and environment-friendly adsorbents.

Key words: Juncus effusus, activated carbon, printing and dyeing wastewater, Rhodamine B, dye adsorption, porous material, biomass material