الفهرس 
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Abstract
The interactions between humic acid and clay are important for modeling the geochemical fate and transport of pollutants in soil upon changes of environmental parameters. br Humic acid was -#99;-#104;-#97;-#114;acterized using elemental analysis and FT-IR spectroscopy to obtain more information on the chemical structure and function groups of the macromolecule. Kaolinite and hematite were used as example for clay. They were -#99;-#104;-#97;-#114;acterized using elemental analysis, BET surface area value and determining particle radius. The rate and the amount of adsorbed humic acid onto clay increased with increasing ionic strength, decreasing pH and in the presence of Ca2+ as background electrolyte. The adsorption equilibrium data showed that HA adsorption could be described more reasonably by Freundlich adsorption isotherm than Langmiur adsorption isotherm. Also, the results explained that humic acid adsorption on hematite and kaolinite was more conforming with pseudo second -#111;-#114;-#100;-#101;-#114; kinetics. br Kinetics of Cu2+ and Zn2+ ions adsorption on kaolinite and hematite in the absence and presence of humic acid have been investigated under various conditions in -#111;-#114;-#100;-#101;-#114; to evaluate the influence of HA. The rate and the amount of adsorbed Cu2+ and Zn2+ ions on clay in the absence and presence of humic acid increased with decreasing ionic strength, increasing pH and in the presence of the background electrolyte K+ rather than Ca2+. In addition, humic acid enhanced the rate and the amount of adsorbed Cu2+ and Zn2+ onto clay. The adsorption equilibrium data showed that adsorption behavior of Cu2+ and Zn2+could be described more reasonably by Langmiur adsorption isotherm than Freundlich isotherm and more conforming to pseudo second -#111;-#114;-#100;-#101;-#114; kinetics.in the absence and presence of humic acid.