Copolymerization of aniline with m-nitroaniline and removal of m-nitroaniline from aqueous solutions using a polyaniline-modified electrode: A comparative study

摘要

Although m-nitroaniline does not homopolymerize, copolymers of aniline with m-nitroaniline (poly(aniline-co-m-nitroaniline)) were readily synthesized in various molar ratios of co-monomers by chemical and electrochemical polymerization. The copolymerization rate decreased with an increasing ratio of m-nitroaniline in the monomer. The prepared copolymers were characterized by UV-vis spectra and FTIR spectra. Due to the presence of electron-withdrawing groups (-NO_2), two main adsorption bands of UV-vis spectra had an obvious blue shift, and the characterized peaks of nitro groups were found in FTIR spectra. The data verified the successful copolymerization of aniline with m-nitroaniline. Besides, m-nitroaniline could polymerize on a polyaniline-modified electrode to generate the polyaniline/poly(mnitroaniline) composite using potential cycling. The formation of the composite was proven by the increase of redox current for the polymerization of m-nitroaniline. FTIR spectra and EDX spectra demonstrated its polymerization. The content of m-nitroaniline polymerized on polyaniline was calculated to be 22.7% of the composite after 50 cycles through XPS analysis. Hence, based on the polymerization of m-nitroaniline on polyaniline, it can be used to remove m-nitroaniline from aqueous solutions.