ZnO Nanofiber Derived from Zinc Loaded Chitosan Nanofiber as an Efficient Adsorbent for Congo Red from Aqueous Solution

In this study, uniform Zn²⁺ incorporated chitosan nanofibers were first prepared by electrospinning with PEO as the cospinning agent and ZnO as the Zn²⁺ source. Then, these composite nanofibers were carbonized at 600 ^oC under argon atmosphere to achieve ZnO embedded carbon (Zn@C) nanofibers. Afterward, these ZnO@C nanofibers were annealed at 400 ^oC under air atmosphere to prepare ZnO nanofibers. SEM, XPS and TEM results confirmed the successful preparation of ZnO nanofibers. The BET analysis shows that the surface area of ZnO nanofibers was up to 154.5 m²/g. These ZnO nanofibers exhibited excellent adsorption performance for Congo red with adsorption capacity of up to 224.2 mg/g. After adsorption, the ZnO nanofibers could be readily recovered by removal of the solution and regenerated by calcination at 400 ^oC for 1.0 h. Due to the fusion of ZnO nanofiber in the regeneration process, the adsorption capacity of ZnO nanofiber was a little reduced after regeneration. The ZnO nanofiber could be reused three times with satisfied adsorption capacity.