The Ability of Azolla filiculoides in Removing Heavy Metals (Cr +3, Cu+2, Ni+2)

Subject Areas : environmental management

Neda Rezai ¹ (دانشجوی کارشناسی، گروه مهندسی محیط زیست، دانشگاه آزاداسلامی، واحد پرند)
Banafsheh Barkhordar ² (Department of Environmental engineering, Parand Branch, Islamic Azad University)

Received: 2010-11-16 Accepted : 2010-12-20 Published : 2014-12-22

Keywords: heavy metals – bisorption - Az,

Abstract :

Heavy metals are very pollutant in the environment as they are stable and can cause toxis, illness, mutagen, etc.,by entering to the food chain. Heavy metals can be reduced by chemical prescription, electrolyze, usingcoagulant, ion exchange, absorption, evaporation and biological methods. Nowadays, removal of heavy metalsfrom water and wastewater by biological absorbants is concerned because of their low cost. Accordingly, a smallaquatic fern, namely Azolla filiculoides, was studies in a batch system to eliminate heavy metals including Cr+3-Ni+2-Cu+2. The tests were done in a batch system through contacting a determined amount of dried biomass ofAzolla filiculoides with heavy metals solution in separated and mixed forms. The tests were carried out inretention times of 5, 10, 20, 30, 45, and 60 min , pHs of 2, 4, 6, and 8, and temperatures of 20, 30, 40 0C. Theobtained results show that increase of pH can increase the percentage of elimination by Azolla filiculoides andincrease of temperature has not a remarkable effect on heavy metals elimination by Azolla filiculoides. Resultsalso show that the aquatic Azolla filiculoides can eliminate Cr+2-Ni+2-Cu+2 with an efficiency of over 97% inretention time of 20 min and reduce them to below the permisable limits of discharge to the environment. It isconcluded that Azolla filiculoides can be effectively utilized in industry.

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