Preparation and characterization of β-cyclodextrin grafted chitosan nanofibers via electrospinning for dye removal

Considering the gradual depletion of water resources, wastewater treatment is important for protecting the ecosystem and the efficient use of water resources. In this study, beta-cyclodextrin (beta-CD) was grafted onto chitosan (CS) backbone to form beta-cyclodextrin grafted chitosan (beta-CD-g-CS). The success of graft copolymerization was characterized using FT-IR, H-1 NMR, TGA, XRD, and EDX analysis. beta-CD-g-CS inherits the cumulative effects of both beta-CD and CS, which was further improved by developing nanofibers. Blend nanofibers of beta-CD-g-CS and polyvinyl alcohol (PVA) were fabricated by electrospinning and monitored by SEM. The optimum conditions for beta-CD-g-CS/PVA nanofibers were determined with the concentration of beta-CD-g-CS 3% w/w, the mass ratio of beta-CD-g-CS/PVA 30:70, applied voltage of 20 kV, solution flow rate of 0.1 mL h(-1), and with the nozzle tip-to-collector distance (TCD) of about 12 cm. Furthermore, the molecular filter performance of the beta-CD-g-CS/PVA(nfm) was investigated using Acid Blue 26 as a model organic molecule. The effects of initial dye concentration, beta-CD-g-CS/PVA(nfm) dosages, optimum pH, time, and interference with other dye molecules were studied. The sorption capacity of the matrix was found to be equal to 296.5 mg g(-1) for Acid Blue 26. In this study, the Langmuir isotherm provided a better fit with experimental data when compared to Freundlich isotherm. The kinetic data for the adsorption of Acid Blue 26 follow the pseudo-second-order kinetic model. These findings indicate the potential application of beta-CD-g-CS/PVA(nfm) as molecular filter to remove the hazardous materials found in wastewater so that the water becomes acceptable for re-use.

Automated summary

Considering the depletion of water resources, wastewater treatment is important for protecting the ecosystem and efficient use of water resources. In this study, beta-cyclodextrin was grafted onto chitosan to form beta-cyclodextrin grafted chitosan, which was further improved by developing nanofibers. The blend nanofibers were fabricated by electrospinning and their performance as molecular filters for removing hazardous materials from wastewater was investigated.