Employing click chemistry in the preparation of β-cyclodextrin-grafted cellulose nanofibers for crystal violet removal from aqueous solutions

<h2>Abstract</h2> Addressing dye effluent removal via adsorption remains a key issue, with ongoing advancements in developing polymeric materials. This study presents β-cyclodextrin grafted regenerated cellulose (β-CD-g-RC) electrospun nanofibers as an efficient adsorbent for removing crystal violet (CV) dye from water-based solutions. The successful synthesis of β-CD-g-RC, with a graft percentage of 11.1%, is validated through analyses of functional groups, elemental composition, surface area, as well as morphological and topographical features. SEM results show that the β-CD-g-RC nanofibers maintain their uniform fibrous morphology with an average fiber diameter of 398 nm after several modification steps. Batch adsorption experiments reveal a CV removal efficiency of 92% under the following conditions: adsorbent dose 14 mg, pH 9, contact time 360 min, initial concentration 4 mg L⁻¹, and temperature 25 °C. The kinetic data fit the pseudo-second-order model, while equilibrium data correlate with the Langmuir isotherm, demonstrating monolayer maximum adsorption capacities of 28.61 mg g⁻¹ and 56.93 mg g⁻¹ at temperatures of 25 °C and 75 °C. Thermodynamic analysis confirms a spontaneous, endothermic, and physisorption-dominated process, as indicated by ΔH° = 20.31 kJ mol⁻¹. The interpretation of the mechanism, along with comparative adsorption studies, demonstrate that electrostatic interactions significantly contribute to the uptake of cationic dyes onto the surface of the nanofibers. The adsorbent exhibits satisfactory reusability, with an 18% efficiency reduction after five cycles. These findings highlight β-CD-g-RC nanofibrous adsorbent as a promising candidate for the decontamination of wastewater from CV.