Phytoremediation technologies for Ni++ by water hyacinth
Phytoremediation of metal contaminated soil and water by Eichhornia crassipes (water hyacinth) is promising. The study was conducted to compare the phytoremoval of Ni++ from soil and wastewater. For the measurement of phytoremoval from soil, E. crassipes was used in a pot experiment. Results showed the removal of (Ni) 24.23 μg/g dry weight of plant and large level calculations show removal of 3449.76 kg/ha of soil, corresponding to 25 μg/g of the added Ni++. In the second experiment, Ni++ contaminated Hoagland’s solution was used for the hydroponic growth of water hyacinth. The result of hydroponic experiment showed the phytoremoval of Ni++ from Ni++ contaminated wastewater; maximum removal was 1.954 μg/g of dry weight. In third experiment, ash of water hyacinth was used for the adsorption and desorption of Ni++. The adsorption capacity was 1.978 μg/g of ash. For the extraction
(desorption) of Ni++, 3 M HNO3 was used. Desorption capacity was 3.71 μg/g of ash. The results of comparative study show order of nickel phytoremediation from soil to be greater than that from water by adsorption which was greater than that from water by hydroponic study. For phytoremoval of Ni++ from soil and water, water hyacinth plant and its ash showed excellence. The desorbed Ni++ can be used in the industries e.g. in Ni plating.
Keywords: Nickel, phytoremediation, soil, waste water, water hyacinth, biosorption