Facile green synthesis of functional nanoscale zero-valent iron and studies of its activity toward ultrasound-enhanced decolorization of cationic dyes.
For the first time, an integrated green technology by coupling functional nanoscale zero-valent iron (NZVI) with ultrasound (US) was innovatively developed for the enhanced decolorization of malachite green (MG) and methylene blue (MB). The functional NZVI (TP-Fe) was successfully fabricated via a facile, one-step and environmentally-benign approach by directly introducing high pure tea polyphenol (TP), where TP contenting abundant epicatechin was employed as reductant, dispersant and capping agent. Note that neither additional extraction procedure nor protection gas was needed during the entire synthesis process. Affecting factors (including US frequency, initial pH, dye concentration, and reaction temperature) were investigated. Results show that TP-Fe exhibited enhanced activity, antioxidizability and stability over the reaction course, which could be attributed to the functionalization of TP on NZVI and the invigorating effect of US (i.e., improving the mass transfer rate, breaking up the aggregates of TP-Fe nanoparticles, and maintaining the TP-Fe surface activity). The kinetics for MG and MB decolorization by the TP-Fe/US system could be well described by a two-parameter pseudo-first-order decay model, and the activation energies of MG and MB decolorization in this new system were determined to be 21 kJ mol-1and 24 kJ mol-1, respectively. In addition, according to the identified reaction products, a possible mechanism associated with MG and MB decolorization with the TP-Fe/US system was proposed.
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China. Electronic address: imusthlee2014@sina.com.
Xiangyu
X
Wang
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China. Electronic address: 18487133554@163.com.
Anqi
A
Wang
School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin, 150090, China. Electronic address: majunhit@126.com.
Jun
J
Ma
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. Electronic address: mlfu@iue.ac.cn.
Minglai
M
Fu
D000975:Antioxidants / Q000737:chemistry; D002412:Cations; D004396:Coloring Agents / Q000737:chemistry*; D055772:Green Chemistry Technology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008751:Methylene Blue / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry; D059808:Polyphenols / Q000737:chemistry; D012394:Rosaniline Dyes / Q000737:chemistry*; D013662:Tea; D013696:Temperature; D014465:Ultrasonics
D000975:Antioxidants; D002412:Cations; D004396:Coloring Agents; D059808:Polyphenols; D012394:Rosaniline Dyes; D013662:Tea; C005095:malachite green; D007501:Iron; D008751:Methylene Blue
Cationic dye; Functionalization; Nanoscale zero-valent iron; One-step green synthesis; Tea polyphenol; Ultrasound