Abstract:In this paper, modified goethite samples doped with different cations were prepared and characterized. XRD showed that doping cations Mn2+, Cr3+ and Al3+ didn't significantly change the types of crystal structure for α-FeOOH, indicating that the cations were doped into the α-FeOOH lattice, and solid solutions were respectively formed when Fe3+ was partially replaced by Mn2+, Cr3+ and Al3+. The infrared analysis also showed a similar result. The results of TGA-DTA and TEM exhibited that these metal cations had entered the goethite lattice. By UV-vis diffuse reflection spectrum analysis, it was found that the band gaps of goethite doped with Mn2+ and Cr3+ were 2.18 and 2.24 eV, respectively, lower than the band gap of pure goethite (2.28 eV); in contrast, the band gap of goethite doped with Al3+ was increased to 2.34 eV. In addition, the reductive effects of different complex systems of Fe(Ⅱ) combined with pure goethite and its counterparts doped with above three different cations on 2-NP reduction were investigated, and it was found that the 2-nitrophenol (2-NP) reductive transformation followed the pseudo-first-order kinetics under the condition pH=6 and temperature 25℃. The system Fe(Ⅱ)/goethite doped with Al3+ showed the best degradation of 2-NP with a removal efficiency of 100% within 120 min. However, the reductive rate of 2-NP transformation was clearly reduced with the initial concentrations of 2-NP increasing to a certain extent. Moreover, the rate constant (k) of the system doped with Al3+ was increased with the increment of the solution pH value.