Screening of few aquatic floating plants for chromium phytoremediation

Phytoremediation process using hydrophytes emerges as an attractive scientific and engineering tool for the attenuation of metal pollution in the aquatic environment particularly in secondary and tertiary levels of wastewater treatment. The selection of appropriate plants on the basis of maximum uptake potential for engineering application of the process is the key factor. The present study deals with the use of four numbers of aquatic plants viz. Pistia, Salvinia, Spirodela and Lemna to assess their relative adsorptive efficiencies for chromium (VI) removal from synthetic solution. The plants were hydroponically cultured in Hoagland solution and grown in conjunction with chromium (VI) spiked solution. All the plants exhibited the ability to tolerate and uptake chromium. The kinetic data showed their uptake capacity in the order viz. Pistia > Salvinia > Spirodela > Lemna. For an initial concentration of 2 mg/L, Pistia could effectively sorbed 0.0457 mg of Cr(VI) /g of biomass with 68.5% Cr(VI) removal efficiency as compared to Lemna which could least achieve a minimum uptake of 0.0307 mg/g of biomass with 46% removal after 7 days of exposure