Biosorption of Pb, Cd, Cu and Zn from the wastewater by treated Azolla filiculoides with H2O2/MgCl2

The adsorption of heavy metals onto treated Azolla filiculoides by H 2O 2/MgCl 2, as a cosmopolitan free-floating waterfern, was investigated from aqueous solutions in the batch biosorption experiments. The maximum uptake capacities of the collected Azolla from rice field at the optimal conditions for Pb, Cd, Cu and Zn ions were approximately 228, 86, 62 and 48 mg/g [dry Azolla], respectively. On the other hand, the maximum uptake capacities of the collected Azolla from the Anzali International Wetland in the north part of Iran at the same conditions for these heavy metals were about 124, 58, 33 and 34 mg/g [dry Azolla], respectively. Such decrease of uptakes is due to the pollution of Anzali International Wetland, which reduces the capacity uptake of metals. The recovery of biosorbed heavy metals from the rice field Azolla was carried out by HCl and NaCl desorbents that the recovery of 64- 86% and 51-72% was occurred, respectively

Toxic effect of Pb, Cd, Ni and Zn on azolla filiculoides in the international anzali wetland

The limitation of plant growth in the polluted mediums can be used as a factor to determine of plant tolerance and the toxic effect of these mediums. In this work, the effect of Pb2+, Cd2+, Ni2+and Zn2+ [individually] on Azolla filiculoides growth in the aqueous solution and using this method to water post treatment were studied. During 15 days the biomass the fresh Azolla with initial mass of 20 g was grown on the nutrient solution containing these metal ions, each in a concentration 4 mg/l. The presence of these ions, caused about 25%, 42%, 31% and 17% inhibition of biomass growth, respectively, in comparison to Azolla control weight which had not heavy metals. The water salinity of 1, 2 and 4 g. NaCl/l decreased the removal of these heavy metals about 4-7%, 20-24% and 40-55%, respectively. The addition of total dissolved solids [TDS] from 50 to 300 ppm. [as CaCO3] into the samples of containing heavy metals increased Azolla growth, but decreased the control Azolla growth