Study On Preparation And Properties Of Polypyrrole/FeOOH/Cellulose Fibers Composite Materials

The problems of energy and environment are eternal theme for human beings.In recent years,the efficient and clean devices of electrochemical energy storage(EES)have been a hot topic as a result of the improvement of flexible electronic information technology.The electrode material plays an important role in EES,which not only satisfies high energy density and long cycle life,but also requires green and sustainable the preparation process.Besides,the rapid industrialization during the past few decades results in the generation of large amounts of wastewater with heavy metals such as lead,mercury,cadmium,arsenic,chromium,etc.,which has become an urgent problem to be solved.Cellulose fibers(CFs)material as a typical representative of biomass resources is a natural polymer with the highest reserves on the earth.It is widely used as a carrier of flexible electrode and adsorbent because of its degradability,regeneration and low cost.Hence,this paper focuses on cellulose fibers(CFs)as flexible substrate to prepare the flexible electrode and adsorption material of heavy metal ion for Cr(Ⅵ).Three kinds of FeOOH with different crystal forms and polypyrrole(PPy)were deposited via in situ method on CFs substrate to obtain ternary composite fibers,the conductivity,capacitive performance,and Cr(Ⅵ)removal ability were studied.The main conclusions are as follows:(1)The FeOOH/CFs composites were prepared by adding sodium acetate to promote the oxidative deposition of ferrous ions on the surface of CFs in an open system,and then PPy was deposited on the above composites via in-situ polymerization with FeCl3·6H2O as oxidant.The PPy/FeOOH/CFs(PFC)paper-based electrode material was prepared by wet-forming process.It is found that compared with PPy/CFs,the PFC paper-based electrode deposited with y-FeOOH nanoscale has higher conductivity,specific capacitance,and rate performance.(2)The α-FeOOH,β-FeOOH,and y-FeOOH were synthesized on the surface of CFs under the same iron ion concentration.The removal performance of Cr(Ⅵ)for the three kinds of composite fibers was compared at different pH values.The result shows that all composite fibers possess certain effect on removal of Cr(Ⅵ),and β-FeOOH/CFs exhibits more excellent performance.(3)The PPy was deposited on the surface of α-,β-and γ-FeOOH/CFs via in-situ polymerization method.The results prove that removal efficiency of Cr(VI)for composite fibers was further improved.This is because the composite structure of FeOOH/CFs improves the effective deposition of PPy,and the generation of new open structure is conducive to the removal of Cr(Ⅵ).Among them,the PPy/β-FeOOH/CFs(β-PFC)has the most excellent removal efficiency,and the optimum adsorption conditions were explored.(4)Different crystal types of FeOOH were synthesized in situ on the surface of PPy/CFs composite fibers.It was found that the composite fiber substrate obtained after the pre-deposition of PPy could improve the loading quality of FeOOH,providing an effective way for its high and stable deposition.However,the higher preparation temperature would cause the oxidation of PPy in the PPy/CFs composite fibers,resulting in a reduction in Cr(VI)removal rate.