Extraction of Copper and Chromium Pollutants with RTILs

• Main Authors: Wei, Yu-Jhe, 魏毓哲
• Other Authors: Huang Hsin-Liang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/29100292677423835904

碩士 === 國立聯合大學 === 環境與安全衛生工程學系碩士班 === 99 === The present work includes the studies of extraction of metal pollutants such as copper on scrap indium tin oxide (ITO) glass and chromium complexes in soil with RTILs (room temperature ionic liquids). Thus, the main objective of this work is to study the speciation of copper and chromium complex pollutants during extracting with RTILs by X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectoscopies, transmission electron microscopy (TEM), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR). By TEM, 80 and 90 nm of nanosize Cu and α-CuI suspend in the a RTIL ([C4mim][PF6], 1-butyl-3-methylimidazolium hexafluorophosphate)-I (I2 + I-) during extraction at 298 K, respectively. By XANES, we found that CuI (64%) and CuI2- (26%) are the main compounds and formed because of reaction of I2, I- and nanosize Cu with grain size of 80 nm, isolating from scrap ITO glass, in the RTIL-I. Moreover, 31P NMR spectra of the RTIL show that interaction of nanoparticles (Cu and CuI) and [PF6]- anions may occur. During extracting, anion of RTIL-I should play an important role to trapping nanoparticles. Experimentally, chromium complexes (chromium chelated with humic acid) in contaminated soils can be extracted with RTILs (1-butyl-3-methylimidazolium chloride ([C4mim][Cl]), 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]), and 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6])). By XANES spectra, the Cr6+-HA (Cr6+ chelated with humic acid) from channels of MCM-41, zeolite Y or ZSM-5 is the main extracted compounds in RTILs. However, it is barely to observe that Cr3+-HA (Cr3+ chelated with humic acid) can be extracted into RTILs. Combined 9F NMR spectra and hydrogen bond basicity of [BF4]-, it seems that Cr6+-HA interacts with [BF4]- by hydrogen bonding. Therefore, high extracted efficiency of Cr6+-HA with RTILs is observed. Furthermore, reduction of Cr6+-HA has also enhanced in RTILs. Interestingly, migration of Cr3+-HA from RTILs into MCM-41, zeolite Y, and ZSM-5 is occured during extraction.