Synthesis and Characterization of Nano-Conducting Copolymer Composites: Efficient Sorbents for Organic Pollutants

Nano-conducting copolymers of aniline (ANI) and pyrrole (Py) with silica of different starting monomer ratios are prepared by oxidative chemical polymerization. X-ray diffraction (XRD) data showed that polyaniline (PANI) is the predominant phase in copolymer composites with a higher starting ANI monomer ratio while polypyrrole (PPy) is the major phase for other prepared samples. Transmission and scanning electron microscope images ascertained XRD results where hexagonal-shaped particles are assigned to PANI/SiO2 and poly(9ANI-co-1Py)/SiO2 samples; the cauliflower morphology can be observed for PPy/SiO2, poly(1ANI-co-9Py)/SiO2, poly(1ANI-co-2Py)/SiO2, and poly(1ANI-co-1Py)/SiO2 samples. One-dimensional nano-fibers can be obtained by using a starting monomer ratio of 2ANI:1Py during synthesis. Thermal analysis showed that copolymerization increases the thermal stability as compared with PANI/SiO2 and PPy/SiO2 composites. All prepared samples were applied as sorbents for Congo red dye from aqueous solutions. It was found that the sorption capacity value was affected by the starting monomer ratio; poly(2ANI-co-1Py)/SiO2 has the highest sorption capacity; the qm value is 142.9 mg g−1 due to its highly-stabilized nano-structure