Perchlorate degradation in aqueous solution using chitosan-stabilized zero-valent iron nanoparticles

As an emerging contaminant, perchlorate has been detected in groundwater, surface water, soil and food worldwide. Perchlorate has good solubility and chemical stability, thus its degradation in water is challenging. Chitosan-stabilized nano Zero-valent Iron (CS-nZVI) was synthesized and tested to degrade perchlorate in water. Chitosan could improve the dispersive property of nZVI, and thus improve its reactivity. Compared with ZVI and nZVI, CS-nZVI exhibited better and faster removal of perchlorate. CS-nZVI exhibited excellent degradation of perchlorate, especially in high-concentration (similar to 200 mg L-1) perchlorate polluted water. The initial solution pH (3-11) and salinity (0.1-30 g L-1) of the solution did not have a significant influence on perchlorate degradation by CS-nZVI after 8 h reaction. Increasing the temperature could enhance the removal efficiency of perchlorate, and the removal rate reached to 96.1% at 92 degrees C with the initial perchlorate of 10 mg L-1. A low activation energy (E-a) of 41.55 +/- 1.93 kJ mol(-1) in the reaction was observed, which was lower than that in other relevant studies. The degradation of per chlorate by CS-nZVI was completed by the interaction of initial adsorption and subsequent reduction. After 8 h reaction, most of the perchlorate (>73%) was completely reduced to chloride with very little byproduct at relatively high reaction temperatures (>85 degrees C). Therefore, this research provides an effective method for perchlorate degradation in contaminated water with high concentrations or high salinity. (C) 2016 Elsevier B.V. All rights reserved.