Environment-friendly Juncus effusus-based adsorbent with a three-dimensional network structure for highly efficient removal of dyes from wastewater

The increasing contamination of water from textile dyes is one of the major environmental problems facing humanity, which has stimulated extensive investigation of fabricating adsorbents with high removal efficiency and excellent adsorption capacity towards textile dyes. Nature has engineered some intriguing high-performance materials that may be excellent sustainable materials for water purification use. Herein, we report a novel Juncus effusus (JE)-based adsorbent with a three-dimensional network structure and interconnected channels for dye removal from wastewater. To further enhance its adsorption capacity towards textile dyes, the biodegradable chitosan (CS) was employed for the chemical modification of the JE fiber. The results showed that the CS–JE fibers exhibited a high adsorption capacity towards three types of anionic dyes at the temperature of 296 K: 526.3 mg g⁻¹ for C.I. Acid Yellow 11 (AY11), 452.5 mg g⁻¹ for C.I. Reactive Red 195 (RR195), and 255.1 mg g⁻¹ for C.I. Direct Blue 15 (DB15), which outperforms most of the reported CS-modified adsorbents. The Langmuir model satisfactorily fitted the equilibrium adsorption curves of the CS–JE fibers. Throughout the kinetics studies, the adsorption fitted well with the pseudo-second-order model and exhibited a two-stage of intraparticle diffusion, indicating the adsorption of the investigated dyes onto the CS-JE fiber is rather complex that both the external surface adsorption and intraparticle diffusion occurred simultaneously. Finally, taking advantage of the specific 3D network structure and interconnect channels of the CS-JE fiber, a vertically oriented CS–JE cake was fabricated using CS–JE fibers for continuous filtration of dyes from wastewater. The cake exhibited high flow flux and rapid filtration performance under continuous flow without requiring additional pressure. The present work confirmed that the CS-JE composite can be a promising candidate for wastewater treatment.