DISSOLUTION OF Cu(OH)2 BY A NOVEL CHELATING SURFACTANT N-LAUROYL ETHYLENEDIAMINE TRIACETATE

摘要

The chelation performance of a novel chelating surfactant (i.e., sodium Hauroyl ethylenediamine triacetate (jV-LED3A)) was evaluated by dissolving Cu(OH)2 in this surfactant. The optimum dissolution equilibrium time was determined to be 120 minutes. The effects of the initial ^-LED3A concentration, temperature, pH and coexisting ions (i.e., Ca(II) and Mg(II)) on Cu(OH)2 dissolution by ^-LED3A were investigated. The ^-LED3A solution significantly enhanced the water solubility of Cu(OH)2via a ligand-promoted hydroxide dissolution mechanism to form a water-soluble chelate complex (^-LED3A-Cu). The mechanism of interaction between Cu(II) and ^-LED3A was further confirmed by Fourier transform infrared spectroscopy (FTIR). The dissolved Cu(II) concentration in the ^-LED3A solution was promoted by increasing the temperature or ^-LED3A concentration. The chelation capacity of ^-LED3 A micelles was stronger than that of monomers. The dissolved Cu(II) concentration was highly dependent on the initial pH of ^-LED3 A. Coexisting Ca(II) or Mg(II) weakened the dissolution of Cu(OH)2 due to competition for ^-LED3A. These results indicate that ^-LED3 A has a strong ability to chelate with heavy metals and form stable water-soluble complexes. The results imply that ^-LED3A was a potential washing agent for heavy metal contaminated soils.