Preparation and characterization of PAni(CA)/Magnetic iron oxide hybrids and evaluation in adsorption/photodegradation of blue methylene dye

•Preparation of PAni(CA)/MOM hybrids by in situ polymerization.•PAni(CA)/MOM hybrids exhibited electrical properties similar to pure PAni(CA).•Hybrid PAni(CA)/MOM nanoparticles exhibited superparamagnetic behavior.•PAni(CA)/MOM reduced the concentration of methylene blue dye by adsorption. In this work hybrids of citric acid doped polyaniline and magnetic iron oxide (MOM) were prepared by in situ chemical polymerization and evaluated in blue methylene dye (MB) adsorption/photodegradation in aqueous medium. The samples were characterized by vibration absorption spectroscopy in the infrared region, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, Mössbauer spectroscopy, vibration sample magnetometry and electrical conductivity measurements using the four-point method. The characterization results showed that magnetic iron oxide consists of magnetite and maghemite phases with superparamagnetic behavior at room temperature. The hybrids materials present magnetic iron oxide particles dispersed in the polymer phase and electrical conductivity of the order of 10−2S cm−1 and showed adsorbent properties. The adsorption process prevails in relation to the photodegradation, but in the hybrids with higher content of MOM an increase in MB removal was observed under UV irradiation, with reduction of 99% of the dye concentration, indicating synergism between the MOM -polymer phases in the photocatalytic action. These results are related to the hybrids morphology. [Display omitted]