title: Enhanced decolorization of methyl orange using zero-valent copper nanoparticles under assistance of hydrodynamic cavitation.
abstract: The rate of reduction reactions of zero-valent metal nanoparticles is restricted by their agglomeration. Hydrodynamic cavitation was used to overcome the disadvantage in this study. Experiments for decolorization of methyl orange azo dye by zero-valent copper nanoparticles were carried out in aqueous solution with and without hydrodynamic cavitation. The results showed that hydrodynamic cavitation greatly accelerated the decolorization rate of methyl orange. The size of nanoparticles was decreased after hydrodynamic cavitation treatment. The effects of important operating parameters such as discharge pressure, initial solution pH, and copper nanoparticle concentration on the degradation rates were studied. It was observed that there was an optimum discharge pressure to get best decolorization performance. Lower solution pH were favorable for the decolorization. The pseudo-first-order kinetic constant for the degradation of methyl orange increased linearly with the copper dose. UV-vis spectroscopic and Fourier transform infrared (FT-IR) analyses confirmed that many degradation intermediates were formed. The results indicated hydroxyl radicals played a key role in the decolorization process. Therefore, the enhancement of decolorization by hydrodynamic cavitation could due to the deagglomeration of nanoparticles as well as the oxidation by the in situ generated hydroxyl radicals. These findings greatly increase the potential of the Cu(0)/hydrodynamic cavitation technique for use in the field of treatment of wastewater containing hazardous materials.
authors.affiliation: School of Environmental Science and Engineering, State Key Laboratory of Control and Resource Reuse, the Collaborative Innovation Center of Advanced Technology and Equipment for Water Pollution Control and the Collaborative Innovation Center for Regional Environmental Quality, Tongji University, 1239 Siping Road, Shanghai, PR China.
authors.forename: Pan
authors.initials: P
authors.lastname: Li
authors.affiliation: School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Song
authors.affiliation: School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, PR China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Dong Hua University, 2999 Renmin Road North, Songjiang District, Shanghai 201620, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Tao
authors.affiliation: School of Environmental Science and Engineering, State Key Laboratory of Control and Resource Reuse, the Collaborative Innovation Center of Advanced Technology and Equipment for Water Pollution Control and the Collaborative Innovation Center for Regional Environmental Quality, Tongji University, 1239 Siping Road, Shanghai, PR China. Electronic address: ysl@tongji.edu.cn.
authors.forename: Shuili
authors.initials: S
authors.lastname: Yu
authors.affiliation: School of Environmental Science and Engineering, Dong Hua University, 2999 Renmin Road North, Songjiang District, Shanghai 201620, PR China. Electronic address: liuyanan@dhu.edu.cn.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Liu
keywords: Agglomeration; Azo dye; Hydrodynamic cavitation; Hydroxyl radicals; Nanoparticle; Zero-valent copper