Extraction of various metal ions by open-chain crown ether bridged diphosphates in supercritical carbon dioxide

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Various toxic metal ions were successfully removed from solid matrix into supercritical CO2 (scCO2) by open-chain crown ether bridged diphosphates at 313.15 K and 20 MPa, these diphosphates with different ester side chains and different length of ethylene oxide bridge group are highly soluble in supercritical CO2. The extraction efficiency (E%) of heavy metals is between 55 and 89%. Mulliken charge distribution of ligand’s P=O coordination group was calculated to indicate the stability of metal complex. The ligand structure effects and the rationale for different selectivity were discussed. In addition, binding property of these diphosphates towards the alkaline earth metals was further studied following the same extraction procedures. Alkaline earth metal ions Ca2+, Sr2+ and Ba2+ were extracted with E% at 49–74%, 50–73% and 16–64%, respectively. DFT calculations were performed to investigate the interaction energy of the complexes and the correlation with the E% was discussed.
Funding Information
  • Zhejiang Provincial Key R&D Program (2018C00136)
  • Young Innovative Talents Program of Educational Commission of Guangdong Province (2019GKQNCX057)
  • National Natural Science Foundation of China (21436010 and 21776240)
  • Jieyang Science and Technology Project (2017xm017)

This publication has 28 references indexed in Scilit: