1,4-Dioxane degradation by oxidation and sonication in the presence of different-sized ZVI in open-air system

Abstract

We investigated the effect of particle size during oxidation and the sono-Fenton process in an open-air system (without air supply) containing microscale zero-valent iron (MZVI) and nanoscale zero-valent iron (nZVI) on the degradation of 1,4-dioxane (1,4-D) at neutral pH. Time-dependent concentrations of 1,4-D, H₂O₂, and ionic Fe were measured as a function of MZVI and nZVI loading during oxidation and sono-Fenton (without addition of H₂O₂). The optimal loading of MZVI and nZVI for 1,4-D degradation were determined to be 0.5 g/L during both oxidation and sono-Fenton, and 0.2 and 0.1 g/L during both oxidation and sono-Fenton, respectively. Overall, the optimal loading of MZVI in both the oxidation and sono-Fenton system showed better 1,4-D degradation efficiency compared with the optimal loading of nZVI for 6 h: approximately 60.00 and 76.65% removal efficiencies for MZVI oxidation and sono-Fenton, respectively, while approximately 47.13 and 60.98% removal efficiencies for nZVI oxidation and sono-Fenton, respectively. Consequently, the smaller size of ZVI did not enhance 1,4-D degradation efficiency during the oxidation and sono-Fenton at neutral pH.

Keywords:

• Zero-valent iron
• Size effect
• Oxidation
• Sono-Fenton
• 1,4-Dioxane degradation

Acknowledgments

This work was supported by the Advanced Biomass R&D Center (ABC) of Korea Grant funded by the Ministry of Education, Science and Technology (ABC-2011-K000908). We would also like to thank Dr. Jung Ho Yoo in Measurement and Analysis Team of the National NanoFab Center (NNFC) for fruitful discussions about SEM and TEM imaging.