Bioremediation of Wastewater Enriched with Cd, Cr and Pb Using Floating Macrophytes

Abstract

This study aimed to explore the effectiveness potential of Eichhornia crassipes, Pistia stratiotes and Salvinia molesta for the reduction of potentially toxic metals from effluents enriched with Cd, Cr and Pb. Based on a 21-day laboratory-scale experiment, a total of three concentrations at 1, 5 and 10 mg/L were selected to culture each of the macrophytes. In addition, kinetics and prediction models were used to analyze the metal reduction data to understand the behavior and removal rate of each species and with the Taguchi methodology to see what the right conditions for greater efficiency are. The results suggested that the three macrophytes was able to reduce metals Eichhornia crassipes manages to reduce 90.8-99.99% Cd, 90.8-99.9% Cr and 89.6-99.9% Pb, for Pistia stratiotes 74.6-99.9% Cd, 74.6-99.9% Cr and 91.2-99.9% Pb and Salvinia molesta 83.2-99.9% Cd, 62.2-99.9% Cr and 89.2-99% Pb. The first-order model it is adjusted appropriately to the removal of toxic metals for the three plants, having an adjustment of R2 greater than 0.80. Taguchi analysis shows that optimal conditions for metal phytoremediation occur with 1 mg/L of toxic metals and after 21 days.