Abstract

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Batch removal of hexavalent chromium from aqueous solutions via grape leaf powder (GLP) and carbon (GLC) as adsorbent, was investigated in this paper. Some experiments were conducted in order to study the adsorption of metal species and effect of different pH values, contact time, metal concentration, adsorbent weight and temperature on Cr (VI) removal. Freundlich, Langmuir and Temkin isotherm models have been utilized to describe the adsorption behavior, so that the experimental results implied that they all followed Langmuir model perfectly (R² = 0.99). The results indicated that the absorption of chromium significantly depends on the pH values of the solution that is, the most proper pH value which may optimize the adsorbent, was found to be pH= 1.5. The optimal time for grape leaves powdered (GLP) was about 60 minutes while it was 90 minutes for carbon (GLC) at the same circumstances. The optimum concentration of grape leaves powder (GLP) was measured about 25 milligrams per liter; however it was 50 grams per liter for carbon (GLC). The adsorbent weight of grape leaves powdered (GLP) and carbon (GLC) were 0.3 g and 0.5g respectively. It should be mentioned that the temperature of carbon (GLC) was 40 C°. Consequently, the results implied that Grape leaf powder (GLP) is stronger adsorbent in comparison with carbon (GLC) to remove hexavalent chromium from wastewater.

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