Evaluating the performance of citric acid as stabilizer and doping agent in an environment friendly approach to prepare electromagnetic nanocomposite particles

Abstract

The objective of this investigation is to find a less‐expensive and less‐toxic environmentally benign route for the preparation of magnetic PANI nanocomposite particles. For this citric acid, a weak organic tricarboxylic acid has been used during seeded chemical oxidative polymerization of aniline in presence of variable amounts of Fe3O4 nanoparticles. Nanosized Fe3O4 particles are first prepared by co‐precipitation of Fe2+ and Fe3+ from their alkaline solutions. Then in the second step, magnetic nanocomposite particles—named as Fe3O4/PANI—are prepared by seeded chemical oxidative polymerization of aniline using ammonium persulfate (APS) as oxidant. Independent of Fe3O4 content, Fe3O4/PANI nanocomposite particles possessed comparable high electrical conductivity having the same magnitude as HCl‐doped PANI particles (2.13 × 10−3 S/cm). This result suggested that addition of citric acid during seeded chemical oxidative polymerization not only promoted solubilization of aniline but also functioned as stabilizer and doping agent. Iron oxide content critically influenced the stability, morphology, and magnetic properties of the produced nanocomposite particles. The saturation magnetization and magnetic susceptibility increased with the increase of Fe3O4 content. The nanocomposite particles prepared with core/shell ratio of 0.6/1 (w/w) exhibited the strongest paramagnetism and aligned into fiber‐like structure. The analysis of electromagnetic properties and spectral data from FTIR, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and thermogravimetry (TG) confirmed the complete coverage of Fe3O4 nanoparticles by PANI layer. POLYM. COMPOS., 39:4628–4636, 2018. © 2017 Society of Plastics Engineers

Single step modification of micrometer‐sized polystyrene particles by electromagnetic polyaniline and sorption of chromium(VI) metal ions from water

“…The stability of PS/PANi–Fe 3 O 4 composite particles was further checked by recording XRD patterns of composite particles before adsorption and after desorption of adsorbed Cr(VI). Figure (b) shows that characteristic diffraction signals of Fe 3 O 4 in composite particles are retained after desorption of Cr(VI) ions . Hence, after first time adsorption, the composite particles remained almost as active as they were before adsorption.…”

“…The residual mass left in PANi–Fe 3 O 4 composite particles suggests the inclusion of around 10% inorganic Fe 3 O 4 . This residual mass of inorganic Fe 3 O 4 is based on the assumption that organic PANi burned off completely at 600 °C, as observed in our previous work . Compared to PANi–Fe 3 O 4 composite particles, the residual mass left in PS/PANi–Fe 3 O 4 composite particles is higher at 600 °C and reached around 17.6 and 39% prepared with lower (1/0.2) and higher (1/0.5) aniline contents.…”

“…Nanosized Fe 3 O 4 particles were prepared according to our previous work . Briefly, simultaneous coprecipitation of Fe 2+ (2.850 g) and Fe 3+ (3.127 g) was carried out from their aqueous solutions containing 25% NH 3 solution (54.0 g).…”

“…So the resulting composite particles having PANi–Fe 3 O 4 shell would possess both electroconducting and magnetic properties. Here, p ‐toluenesulfonic acid ( p ‐TSA) was used as a dopant and citric acid, a weak and easily available organic acid, was used as a stabilizer and solubilizing agent for aniline . The morphology, size distribution, surface composition, and magnetic property of composite particles were analyzed by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR), X‐ray photoelectron spectroscopy (XPS), thermogravimetry analyzer (TGA), and vibrating sample magnetometer (VSM).…”

“…Here, p-toluenesulfonic acid (p-TSA) was used as a dopant and citric acid, a weak and easily available organic acid, was used as a stabilizer and solubilizing agent for aniline. 33 The morphology, size distribution, surface composition, and magnetic property of composite particles were analyzed by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetry analyzer (TGA), and vibrating sample magnetometer (VSM). The utility of micrometer-sized PS/PANi-Fe 3 O 4 composite particles was then analyzed as adsorbent for the removal of toxic Cr(VI) ions from water.…”