Effect of Iron and Aluminum on Adsorption of Fulvic Acids on Norit ROW 0.8 Supra Carbon

摘要

The article presents the results of a study on adsorption of fulvic acids on the activated carbon NORIT ROW 0.8 Supra. Examination of the adsorption process was preceded by an in-depth analysis of the adsorbate and the adsorbent. Effect of the solution pH (3.0, 6.5, and 9.0) as well as aluminum and iron ions (c = 5 mg/dm(3)) on the adsorption process was examined. The highest multiple correlation coefficients were obtained for the Al(III) solution at pH 3.0 and for Freundlich and Langmuir isotherms were equal 0.995 and 0.989, respectively. Values of isotherms coefficients varied depending on the solution pH and the presence of cations. The most effective adsorption for the specific type of carbon was observed in an alkaline environment. Presence of metal ions increased the adsorption efficiency in an acidic environment, while decreased it in an alkaline one. At pH 3.0, the presence of Fe(III) ions increased a(m) from 10.7575 to 22.2794, while k(L) changed from 0.2003 to 0.1360. At pH 9.0, the above coefficients changed as follows: a(m) from 30.707 to 16.0811 and k(L) from 0.0065 to 0.0740. Models of hydroxo complexes formed by ions in an aquatic environment were used to explain how metal ions influenced adsorption. Our results clearly indicate that metal ions back adsorption of FA only when the active carbon surface is positively charged and the solution is acidic.