Synthesis and characterization of a conducting polyaniline/α-Fe₂O₃ magnetic composite powder via one-step in situ polymerization for use as an adsorbent material for cationic dyes

The methylene blue is a cationic dye that's major harmful to the water. A simple, cost-effective solution is to use conductive polyaniline/metal oxide composites to remove it through adsorption. A one-step in-situ polymerization technique was used to fabricate the polyaniline (PAni) composites, utilizing iron oxide (hematite α-Fe₂O₃) particles as precursors. The characterization of the as-prepared PAni/α-Fe₂O₃ composites was conducted using various complementary techniques, including Fourier-transform infrared spectroscopy, UV/vis spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), X-ray diffraction, conductivity measurements, vibrating sample magnetometer (VSM), and cyclic voltammetry. The catalytic potential of both PAni and PAni/α-Fe₂O₃ composites was evaluated in the context of MB dye degradation, highlighting the influence of varying weight percentages of α-Fe₂O₃ in the composite. All composites have contained Fe₂O₃ material (as confirmed by XRD) with enhanced crystal size by increasing Fe₂O₃ percentage. This presence has strengthened by the SEM and AFM images, which vividly confirmed the presence of Fe₂O₃ particles on the polyaniline surface. Optical spectra, and VSM analyses have affirmed the interaction between polyaniline and Fe₂O₃ particles. Remarkably, the PAni/α-Fe₂O₃ composite with 40 % α-Fe₂O₃ exhibited impressive degradation efficiency, achieving 95.16 % removal rate of methylene blue. This outcome underscores the high catalytic performance of the composite and its potential as an efficient catalyst for the removal of MB dye, particularly under conditions without UV irradiation.