Abstract
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 q(m) value is 142.9 mg g(-1) due to its highly-stabilized nano-structure.