Optimization of Mercury Adsorption Process from Aqueous Solutions using Polypyrrol/clinoptilolite Composites with Taguchi Method

The release of heavy metals into the environment has caused major problems around the world due to industrialization and urbanization. The aim of this study was to examine the possibility of mercury (Hg(II)) removal from aqueous solution in batch process using synthesized functional polypyrrol/ clinoptilolite nanocomposite. The morphology and functional groups of the nanocomposites were characterized using scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR) and BET. The adsorbent modified was used to remove mercury from aqueous solution. The experiments and optimization were performed based on experimental design with three levels of variables using Taguchi method. Results revealed that in mercury sorption tests in aqueous solution, pH solution has the greatest impact on the removal efficiency of mercury and mercury sorption in the alkaline conditions is more than acidic and neutral solution. The highest removal efficiency of mercury (approximately 95%) from aqueous solution with a concentration of 50 mg/l was obtained in the values ​​of the third level of the operational variables pH, contact time, and adsorbent mass, which were 10, 30 min and 0.35 g, respectively. The concentration of mercury ions in aqueous solution was measured using an atomic absorption spectrometer. The study of adsorption isotherm models was performed by four isotherms of Langmuir, Friendlich, Dabinin Radskovich, and Tamkin. The results showed that the maximum adsorption capacity of mercury by polymer composite was 42.37 mg/g.