Removal of Toxic Hexavalent Chromium From Aqueous Solutions Using Polyaniline Modified Pine Cone

Growing industrial development and population explosion in the world resulted in an increasing amount of different pollutants daily discharged into the environment. Some pollutants, such as heavy metals, even at low concentrations, are harmful to human health. Chromium is not naturally found in water; however, it enters the environment as chromate and dichromate through industrial pollution[۱] caused by effluents from metal plating, tanning, dye making, and stereotyping workshops and by oil varnish and ink. Several methods are used to minimize these harmful pollutants. The adsorption process using polymer modified biosorbents is a good option for removing pollutants from water due to low-cost and simple operation. In This work pine cone/polyaniline composite was prepared by in-situ polymerization of aniline in the presence of pine cone powder. After polymerization, the pine cone/polyaniline composite was washed with distilled water and then dried in an oven at ۶۰ centigrade degree. The pine cone/polyaniline composite was characterized by FT-IR spectroscopy. The composite was used as adsorbent to remove Cr(VI). As seen in the figure, modification of pine cone powder with polyanilineintensively enhanced the chromate removal. The removal of chromium from water can be explained by electrostatic interaction between negatively charged chromate and positively charged sites on the polyaniline emeraldine salt. The removal efficiency was reached over ۷۰ percent after ۸۰ minutes. The equilibrium adsorption capacity increased from ۸.۹ mg/g for pine cone powder, to ۷۸.۲ mg/g for pine cone/polyaniline composite as a result of modification of pine cone powder with polyaniline.