| Organic/inorganic composite materials have attracted more and more attention in the field of new materials because of the resultant materials combining the advantages of both the organic and inorganic components. Moreover, as an electronic-ion mixed conductor, electroactive organic/inorganic materials may be widely used in new technologys. In the past few years, much interest has been drawn in the study of the ion exchange behavior of the electroactive materials. With the development of research, a novel ion separation method called electrochemically switched ion exchange (ESIX) was obtained, which is an environmentally benign way to separate ions via reversible electrochemical modulation of the matrix charge density. As its clean and safe character, the technology has gradually become a hot topic among researches. For this reason we have carried on the preliminary discussion and the research of the synthesis and ESIX property of an electroactive composite material ’polyaniline/a-zirconium phosphate (PANI/a-ZrP)’.Electroactive PANI/a-ZrP films with diferent a-ZrP synthesised via reflux and hydrothermal method were prepared on the platinum by unipolar pulse deposition(UPD). On the basis of the previous researches, we studied the doping mechanism, structure, ESIX schematic of the materials. The electroactive of films was tested by cyclic voltammetry (CV). X-ray diffraction (XRD) was used to investigate the crystal structures of zirconium phosphate (ZrP) and PANI/α-ZrP. The morphologies and componenents of materials were characterized by scanning electron microscope (SEM) and fourier transform infrared spectrometer (FTIR). Energy dispersive X-ray spectroscopy (EDS) combined with X-ray photoelectron spectroscopy (XPS) were used to analyzed the elementary composition of PANI/α-ZrP films in oxidation and reduction state. The results showed that:Electroactive PANI/α-ZrP composite materials can be prepared by UPD. The electrostatic attraction between PANI and α-ZrP promotes the composite process. PANI/α-ZrP films have reversible electrochemical activity in aqueous solution containing Ni2+. By comparison, when α-ZrP was synthesised by reflux method, the PANI/α-ZrP are higly oriented films and display perfect electrochemical properties. What’s more, the synthetic route of reflux method is much simpler and the yield is more higher. For these reasons, α-ZrP synthesised by reflux method is more suitable to be used as the original material of PANI/α-ZrP composite films.Based on the above research, electroactive PANI/α-ZrP with α-ZrP obtained via reflux method composite films were synthesized by UPD through controlling the polymeric parameters in the process of deposition. The preparation factors to the electrochemical behavior and dynamics performance of PANI/α-ZrP films were tested by CV. FTIR and XRD were used to study the componenents and crystal structures of the films with different concentrations of aniline. The ESIX properties in aqueous solution containing Ni2+were investigated by electrochemical quartz crystal microbalance (EQCM) technique, XPS were used to analyzed the elementary composition of PANI/α-ZrP films in oxidation and reduction state. Experimental results indicated that:PANI/α-ZrP composite films prepared under the3.5V pulse potential,700pulse number,0.02mol/L aniline have high ion exchange capacity and excellent electronic-ion transfer properties. Moreover, by modulating the potential of PANI/α-ZrP films, Ni2+uptake or elution from film can be controlled. The reduction and oxidation state of PANI/α-ZrP correspond to Ni2+enter or release from the film, respectively. The composite film can be used to separate Ni2+from aqueous solutions. Compared with the traditional ion exchange process, the adsorption amount of Ni2+by PANI/α-ZrP film with potential can be up to75%in shortening of40%time, meanwhile, the removal rate of Ni2+is significantly improved. |
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