| Abstrakt: |
The desorption test was conducted to evaluate the desorption behavior of Pb(II) and Cd(II) using citric acid. The influential factors that were considered included initial Pb(II), Cd(II) contamination levels in soil, concentration of citric acid, reaction time, soil pH value and ionic strength. The test results indicated that the desorption was a rapid reaction (less than 6 h), and the removal percentages of Cd(II) and Pb(II) increased with the increasing contamination levels, concentration of citric acid and the addition of Na, Ca, Cl. However, the desorption of Pb(II) and Cd(II) decreased with the addition of SO because of the precipitation in the form of MSO(s). The high pH condition indicated a negative effect on Pb(II) desorption. The removal percentage decreased from 71.39% to 10.9% as pH increased from 2 to 10.8. The desorption behavior predicted by Visual MINTEQ was in good agreement with the experimental testing result. The results of X-ray diffraction (XRD), X-ray fluorescence (XRF) and N2-BET adsorption test demonstrated that the desorption behavior of heavy metals (i.e., Pb(II) and Cd(II)) was controlled by the affinity of sorption sites for heavy metals, the competition of H, Ca, Na, Cl and the chelating of organic ligands. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink