General Cleanup Technology

Separation of organic contaminants from groundwater by complexation with the macrocyclic ligand Cucurbituril

Cucurbituril is a macrocyclic ligand which is able to remove aromatic compounds from aqueous solutions. In these complexes the hydrocarbons are located inside the hydrophobic cavity of cucurbituril. In the regeneration process ozone destroys the substances included in the cavity of cucurbituril without oxidising the macrocyclic ligand itself. Several charging/regenerating cycles are possible.

Summary

In this project the knowledge base for a new process for the removal of aromatic substance from aqueous solutions with the macrocyclic ligand “Cucurbituril” has been developed.

Procedure:

  1. In the first step the aromatic hydrocarbons are separated from aqueous solutions with the macrocyclic lidand cucurbituril.
  2. Afterwards the charged ligand is regenerated by destroying the included hydrocarbons with ozone. The regenerated ligand can be reused to separate aromatic compounds from aqueous solutions.

Results:

  • Cucurbituril is able to remove BTX-aromatics, chloro- and nitroaromatics, anilines and polynuclear aromatic compounds from aqueous solutions. In these inclusions complexes with 1:1 stoichiometry the aromatic molecule is located inside the hydrophobic cavity of cucurbituril. Salts or humic acids decrease the efficiency of the separation of aromatics from ground- and leak water. By using an excess ratio of cucurbituril to the pollutants the influence of accompanying substances can be ignored.
  • Cucurbituril is fixed on the substrate SiO2 (silicon oxide). This enables a good flow through a filled pillar. Silica gel can easily be modified by cucurbituril. It is also inert against oxidation by ozone and very reasonable.
  • Ozone destroys the substances included in the cavity of cucurbituril without oxidising the macrocyclic ligand itself. Even after several charging/regenerating cycles no decrease in the separation capacity of cucurbituril for aromatics is observed.

More Project Information

Project title: Separation of organic contaminants from groundwater by complexation with the macrocyclic ligand Cucurbituril

Project number: 02WT9730/1

Project period: 1997 - 1999

Project region: Germany (North Rhine-Westphalia)

Project contact:

Herr Dr. Buschmann
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Source: German National Library of Science and Technology Hannover (TIB)