Porous cage-like microfiber of fly ash magnetic powder (CMS)/polyaniline (PANI) composites with absorption properties

Abstract

In order to recycling adsorbent of wastewater, magnetic adsorbents with recycling properties were prepared by fly ash magnetic powder (CMS)-doped polyaniline microfiber composites (CMS/PANI microfiber). The cheap fly ash magnetic powder is obtained from industrial solid waste fly ash. XRD patterns of CMS/PANI microfiber shows that the peaks at 30° are corresponding to the magnetite in CMS. SEM images shows that CMS/PANI fibrous winding structures forming a porous cage, where microfiber have the diameter of 60 nm and the length of 2–3 um. EDS spectra indicated that the magnetic dots monodispersed on the surface of every root of microfiber. BET surface areas of PANI microfiber and CMS/PANI microfiber are 36.42 m2 g−1 and 25.75 m2 g−1, respectively. The different wastewater samples has been used including congo red(CR), methyl orange(MO) and halogenated element ions solutions. The maximum adsorption amounts of CR and MO were 324.68 mg g−1 and 212.3 mg g−1, respectively. Interestingly, the CMS/PANI nanofibre material still adsorbs very well to other ionic wastewaters. The magnetic adsorbent achieves a sorption rate of 70% for Ca2+ containing wastewater under certain conditions. The magnetic adsorbent exhibited 48% adsorption of Cl− and over 90% adsorption of F−, Br− and I−. After six cycles of magnetic separation, the adsorption rate was still above 96%. The adsorption curves and equation fits show that the adsorption process is consistent with the langmuir isotherm model and the quasi-secondary kinetic model.