Synthesis of cellulose acetate/chitosan/SWCNT/FeO/TiO composite nanofibers for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions.

The potential of electrospun cellulose acetate/chitosan/single walled carbon nanotubes/ferrite/titanium dioxide (CA/chitosan/SWCNT/FeO/TiO) nanofibers was investigated for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions via the adsorption and photocatalytic reduction processes. The properties of synthesized SWCNT/FeO/TiO and fibers were characterized using TEM, SEM, FTIR, XRD, TGA and BET analysis. In adsorption process, the influence of adsorbent type including SWCNT to FeO ratio, TiO to SWCNT/FeO ratio and SWCNT/FeO/TiO concentration as well as the adsorption parameters including pH, contact time, and initial concentration of adsorbates on the Cr(VI), As(V), Methylene blue and Congo red adsorption in a batch mode was investigated. The reusability of nanofibers was also investigated for five adsorption-desorption cycles. The photocatalytic reduction of Cr(VI), As(V), Methylene blue and Congo red was also investigated using various nanofibrous catalysts. The obtained results indicated that the removal of Cr(VI) and As(V) using CA/chitosan/SWCNT/FeO/TiO nanofibrous adsorbent via adsorption process could be preferred for the lower concentrations of metal ions. The photocatalytic reduction was an effective method for the Cr(VI), As(V) removal at higher concentrations and degradation of Methylene blue and Congo red under both lower and higher concentrations of azo dyes.