Kinetics of reductive degradation of Orange II in aqueous solution by zero‐valent iron

The reductive degradation of Orange II in aqueous solution by zero‐valent iron was investigated. The degradation of Orange II followed pseudo‐first‐order kinetics at various pH values and initial Orange II levels, but the formation of sodium sulfanilate, a major reductive product of Orange II, followed zero‐order kinetics. Copyright © 2004 Society of Chemical Industry     

Application of nickel (II) complex of dithiocarbamate‐modified starch for anionic dyes removal from aqueous solutions

The work presents the synthesis of nickel (II) complex of dithiocarbamate‐modified starch (DTCSNi). It is characterized by elemental analysis, infrared spectrum, and thermogravimetry methods. A batch system was applied to study the adsorption of DTCSNi for four anionic dyes removals. The adsorption with respect to the pH was investigated. It is found that the capacity of DTCSNi for each dye is pH dependent, and the adsorption is governed by coordination. At the suitable pH 4, two kinetic models, that is, pseudo‐first‐ and pseudo‐second‐order, were tested to investigate the adsorption process. The kinetic parameters of the models were calculated and discussed. The results suggest that the best fit model is the pseudo‐second‐order equation. The Langmuir–Freundlich model agrees very well with experimental data and the maximum adsorption capacity sequence is AO7 > AG25 > AR18 > AO10. The Fourier transform infrared spectra and thermogravimetric analysis verified the chelating molecular mechanism. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012