Graphene oxide (GO) significantly affects the electrochemical activity of its composite with polyanline titanium dioxide (TiO2). In this work various composites with different GO contents have been successfully synthesized by chemical method to compare not only their material properties but also electrochemical characteristics with each other. The results of an electrochemical impedance study showed that their electrochemical property has been improved due to the presence of GO in a composite matrix. The galvanodynamic polarization explained that among them the composite with GO/Ani ratio in the range of 1–14 exhibits a better performance compared to the other due to yielding a higher current desity (280 μA cm−2). The TEM and SEM images which presented the fibres of a composite bundle with the presence of PANi and TiO2 were examined by IR-spectra and x-ray diffraction, respectively.

Composites based on polyaniline (PANi) and rice husk (RH) were prepared by two methods: the first one was chemical method by combining RH contained in acid medium and aniline using ammonium persulfate as an oxidation agent and the second one was that of soaking RH into PANi solution. The presence of PANi combined with RH to form nanocomposite was clearly demonstrated by infrared (IR) spectra as well as by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. Lead(II) and cadmium(II) ion concentrations in solution before and after adsorption process on those composites were analysed by atomic adsorption spectroscopy. Of the above preparation methods, the soaking one provided a composite onto which the maximum adsorption capacity was higher for lead(II) ion (200 mg g −1 ), but lower for cadmium(II) ion (106.383 mg g −1 ) in comparison with the chemical one. However, their adsorption process occurring on both composites also fitted well into the Langmuir isotherm model.

TiO2-polyaniline (PANI) composites were prepared by thermal oxidation of titanium substrate combined with chemical polymerization of aniline. Their chemical structures were determined by infrared (IR) spectroscopy and x-ray analysis. Their morphological structures were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Their electro- and photoelectrochmical properties were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis. The results showed that their photoelectrochemical behavior was better than that of TiO2 electrode; among them the more PANI existed in composite the higher was the anodic photoelectrochemical current. It was also found that the composite has structure in the range of nanosize.

a b s t r a c tHybrid nanostructured composite by polyaniline (PANi) and maize tree-trunk (MTT) was prepared by chemical polymerization method. Its structural morphology was nano range through SEM and TEM images. The decomposition temperature of PANi-MTT composite for 61.9% was about 341°C, less than that of PANi (about 507°C) for 46.6% through thermal analysis. It means this composite is less thermal stable than pure PANi because of MTT presence in composite matrix. The conductivity of PANi-MTT in salt form was 0.597 mS cm -1 , much smaller than that of pure PANi (35 mS cm -1 ) in the same state. The adsorption isotherm process of lead (II) and Cd (II) on PANi-MTT followed by Freundlich model better than by Langmuir one thanks to higher correlation coefficients (~1). It occurred spontaneously and fitted into the second order reaction. The maximum capacities were 121.951 mg g -1 and 54.645 mg g -1 for Pb 2+ and Cd 2+ ions, respectively.

Polyaniline titanium dioxide (PANi-TiO