Comparison of Granular Activated Carbon, Natural Clinoptilolite Zeolite, and Anthracite Packed Columns in Removing Mercury from Drinking Water

Document Type : Research Paper

Authors

1 Assist. Prof. of Environmental Health Eng., Faculty of Public Health and Center of Health Research, Hamedan University of Medical Sciences

2 Grad. Student of Environmental Health, Faculty of Public Health, Isfahan University of Medical Sciences

3 Faculty Member of Public Health and Center of Health Research, Sabzevar University of Medical Sciences

Abstract

Development of effective methods for the removal of such pollutants as heavy metals (e.g., mercury) from surface and ground water resources introduced by municipal and industrial wastewaters seems to be inevitable, especially in the face of the importance of water reuse in combating water shortages, limited availability of water resources, and imminent risks of a water crisis in Iran. A number of methods are already available for the removal of mercury from water resources. However, these techniques must be investigated for their practicability and economy, in addition to their not only effectiveness. In this research, granular activated carbon, natural zeolite, and anthracite packed-columns were investigated as cheap and effective adsorbents for the removal of mercury. Moreover, the effects of changes in pH (6-8), influent mercury concentrations (0.25, 0.5, 0.75, and 1 ppm), contact time (0.5, 1, 2, 3 hr) were investigated. Mercury concentration in the samples was determined using a ditizon indicator and spectrophotometry at 492 nm. Results showed that decreasing influent mercury concentration from 1 ppm to 0.25 ppm (under constant conditions) increased the removal efficiencies of anthracite, granular activated carbon, and zeolite columns from22%, 63%, and 55% to 28%, 72%, and 64%, respectively. Increasing contact time from 0.5 hr to 3 hr caused the removal efficiencies of these columns to increase from 22%, 56%, and 54% to 42%, 86%, and 82%, respectively. Also, increasing pH level led to increased removal efficiencies of the studied columns. It was found that contact time played a more effective role in enhancing mercury removal efficiency in the granular activated carbon column than in the other two columns. The ranges of mercury removal efficiency obtained for the granular activated carbon, natural zeolite, and anthracite columns under various conditions were (51%-92%), (42%-88%), and (16%-52%), respectively. Based on these results, granular activated carbon could be recommended as an effective and cheap adsorbent for the removal of mercury from drinking water resources. 

Keywords


1- شریعت پناهی، م. (1372). مبانی بهداشت محیط، انتشارات دانشگاه تهران، تهران.
2- شریعت پناهی، م. (1377). اصول کیفیت و تصفیه آب و فاضلاب، انتشارات دانشگاه تهران، تهران.
3- کی‌نژاد، م. ع.، و ابراهیمی،س. (1380). مهندسی محیط زیست آب و فاضلاب، انتشارات سهند، تبریز.
4- اسدی، م.، و نبی‌زاده، ر. (1377). مدیریت مواد زائد خطرناک، انتشارات سازمان حفاظت محیط زیست، تهران.
5- ناصری، س.، و قانعیان ، م. (1381). مدیریت کیفیت آب، انتشارات نصر، تهران.
6- ملاح، م. (1377). تعیین ساختار و بررسی خواص تبادل یک نوع زئولیت.پایان‌نامه کارشناسی ارشد، دانشکده علوم، دانشگاه تهران.
7- ابوالحمد، گ.، زاهدی، چ.، و خدایاری، ش. (1382). بهینه سازی کربن فعال به روش فعال‌سازی شیمیایی. مجله مهندسی شیمی ایران، 8، 20-27.
8- AWWA, APHA,WPCF. (1994). Standard  methods for the examination of water and wastewater, 18th Ed., American Health Association Publication Office,USA.
9- Singh, H.B., Kumar, B., and Sharma R.L. (1989). “Direct spectrophotometric  determination of trace amounts of mercury in aqueous media as its dithizonate complex in the presence of a neutral surfactant.” J. of Analyst, 114, 853-855.
10- Saglam, N., Say, R., Denizil, A., Pattr, S., and Arca, M.Y. (1999). “Biosorption of inorganic mercury and alkyl mercury species on to Phanerochaete chrysosporium mycelium.” J. Process Biochem, 34, 725-730.
11- Tchobanoglous, G., and Burton, F. (1991). Wastewater engineering treatment, disposal and reuse, 4th Ed., McGraw-Hill, Metcalf and Eddy,Boston.
12- درایت ، ج.، رضایی، ع.، مرتضوی، س.، یمینی، ی.، خوانین، ع.، و سلیمانی، ا. (1384). مطالعه عوامل موثر در حذف جیوه از محلول‌های مائی با استفاده از گرانول کربن فعال. فصلنامه علمی پژوهشی دانشگاه علوم پزشکی کرمانشاه. 9 (1)، 44-51.
13- Genc-fuhrman, H., Mikkelsen, P.S., and Ledin, A. (2007). “Simultaneous removal of As, Cd, Cu, Ni and Zn from stormwater:Experimental comparison of 11 different sorbents.” Water Research, 41,591-602.
14- طالبی ، م.، تولی ، ت.، و حسین زاده، م. (1381). حذف جیوه از فاضلاب‌های صنعتی به روش شیمیایی. اولین سمینار شیمی محیط و زیست ایران، دانشگاه یاسوج، 31.
15- بازدار ، م. (1379). جداسازی مواد معدنی و آلی توسط کربن فعال. پایان‌نامه کار شناسی ارشد ، دانشگاه تربیت معلم تهران .
16- Chiarle, M., and Rovatti, M. (2000). “Mercury removal of water by ion exchange resins adsorption.” J. of Water Research, 34 (11), 2971-2978.
17- Zhang, F., and Nriagu, O. (2005). “Mercury removal from water using activated carbons derived from organic sewage sludge.” J. of Water Research,  39 (2-3), 389-395.
18-Shah, R., and Devi, S. (1994). “Spectrophotometric determination of micro quantities of silver  using dithizone in the presence of cetyl trimethyl amonium bromide.” Indian J. of chem., 34, 925-927.
19- Ullman, M. (2003). Encyclopdia of industrial chemistry, 6th Ed., Wiley-VCH Publishers, N.Y.
20- Skodras, G., Diamantopoulou, I., and Sakellaropoulos, G.P. (2007). “Rolof activated carbon structural properties and surface chemistry in mercury adsorption.” Desalination, 210 (1-3), 281-286.