Experimental
Reagents and instruments
All reagents used were of analytical reagent grades and were purchased from the Merck company (Darmstadt, Germany). All the solutions were prepared with double- distilled water with zero levels of dissolved oxygen. Iron stock solution was prepared by (NH4)2Fe(SO4)2·6H2O. The stock solution was diluted further to obtain the standard solutions. Ortho-phenanthroline solution was prepared by dissolving 1 g of 1,10-phenanthroline mono- hydrate in water and diluting to 1,000 mL. Buffer solu- tion (pH = 6) was prepared by dissolving appropriate amounts of ammonium acetate in acetic acid. Iron con- centration was obtained from absorbance measurement by a Jenway spectrophotometer model 6505 (Jenway, England, UK). Measurements of pH were made with a Jenway 3510 pH meter using a combined glass electrode.
Conclusion
In this study, pomegranate peel carbon biosorbent was applied successfully for the biosorption of Fe(II) from aqueous solution. The kinetic studies proved that the first- order kinetic was the best applicable model. The isotherm equilibrium studies confirmed that the Langmuir form and generalized models were the highest fitted models for the adsorption process. The maximum adsorption poten- tial of pomegranate peel adsorbent for Fe(II) removal was ca. 18.5 mg g−1. Thermodynamic parameters showed that the adsorption process was exothermic and spontaneous. The comparison of this study with the previous studies shows that the new biosorbent has more ability than the other waste biomasses for removing Fe(II).