Removal of Methyl Orange Dye Using Polyaniline Modified Walnut Shell

Exposure to water pollutants is one of the major threats to human health. Annually, large volumes of wastewater enter the environment from industrial, agricultural and domestic units, including high concentrations of organic and inorganic chemicals such as hydrocarbons, dyes, Pesticides and heavy metals [۱]. There are several common methods for minimizing these harmful pollutants. Among these methods, the adsorption process by low-cost and simple operation biosorbents coated by polymers with porous structures is a good option for removing pollutants from water [۲].In this study, polyaniline-modified walnut shell used as sorbent to investigate the removal of methyl orange dye from water. The polyaniline-modified walnut shell was prepared by in-situ polymerization of aniline in the presence of walnut shell powder. After polymerization, the produt was washed with distilled water and then dried in an oven at ۶۰ centigrade degree. The sorbent was characterized by field emission scanning electron microscopy and FT-IR spectroscopy. Removal experiments were performed at room temperature and pH= ۴.۵, with dye initial concentration of ۲۵ mg/L over ۸۰ minutes. Dye concentration was determined at time intervals by measuring the absorption values using UV-vis spectrophotomrty at λmax of ۴۶۴ nm.As can be seen in the figure above, unmodified walnut shell is not able to remove the dye. while after modification with polyaniline, the removal efficiency and capacity reach ۱۰۰% and ۱۲۵ mg/g (in ۸۰ minutes), respectively. These results show that modifying walnut shell with polyaniline has a significant effect on removing methyl orange dye.