Coordination of Modified PAN Fibers with Fe3+ and Catalytic Activity of Their Complexes for Dye Degradation

The amidoximated PAN fiber(denoted as AO-PAN) and the mix-modified PAN fiber(denoted as M-PAN) were prepared with hydroxylamine and its mixture with hydrazine, and then used to coordinate with Fe3+ respectively, to produce two Fe-modified PAN fiber complexes (denoted as Fe-AO-PAN and Fe-M-PAN, respectively). Coordinating kinetics of both modified PAN fibers with Fe3+ was mainly studied, and effect of temperature and Fe3+ initial concentration on coordinating kinetics were also examined. The catalytic activities of both Fe-modified PAN fiber complexes were investigated in the oxidative degradation of an azo dye (Reactive Red 195) by DRS and ESR methods. The results indicated that within the observed temperature and concentration range, equilibrium data for the coordination of Fe3+ with two modified PAN fibers were obtained and correlated with Langmuir and Freundlich isotherm equations, and coordination kinetics showed better agreement with the Lagergren second order equation. Fe coordinating capacity and reaction rate constant of AO-PAN to Fe3+ were higher than those of M-PAN to Fe at the same conditions, indicating that AO-PAN reacted with Fe3+ more easily than M-PAN. Two Fe-modified PAN fibers complexes have the significant catalytic effect on dye degradation, and Fe-AO-PAN showed the stronger catalytic performance than Fe-M-PAN in the dark. Moreover, catalytic ability of the Fe-modified PAN fiber complexes, especially Fe-AO-PAN was remarkably enhanced by light irradiation.