Removal of chromium (VI) from aqueous environments using composites of polyaniline-cherry leaves

Composites of Polyaniline (PANI)-prune, peach, cherry, grape, fig and walnut leaves were synthesized under various conditions and were used to remove chromium (VI) from aqueous environments in discontinuous experiments. The results showed that the highest percentage of Cr (VI) removal (40.3%) belonged to the composite consisting of cherry leaves and PANI. Synthesis conditions of this composite were then studied to increase Cr (VI) removal. The results of the experiment on the various solvents are used in the synthesis of the composite of PANI-cherry leaves indicated that the best solvent (with 40.93% Crn(VI) removal) was water. The effects of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) as additives on the synthesis of the composite PANI-cherry leaves were studied and it was revealed that the best-synthesized composite (with 51.64% Cr removal) was produced in presence of PVA (2 g/L), and the optimum pH and contact time were 2 and 30 min, respectively. Moreover, the adsorption process followed Langmuir and Freundlich adsorption isotherms, and the maximum Cr adsorption capacity was 33.01 mg/g. The results of the FTIR and XRD tests and SEM images for this composite were studied. The SEM images demonstrated that the addition of PVA reduced the size of the particles and made them more uniform. The XRD test indicated that the synthesized composite was amorphous, and the FTIR test confirmed the synthesis of the composite.