Removal of Cadmium from Water by Water Hyacinth

Abstract

Heavy metals and other trace contaminants enter surface and groundwater in various ways and adversely affect fauna and flora. Thus, the removal of such impurities is necessary. The heavy metals, in general, are either precipitated as sulfides or oxides. In a few cases, ion exchangers have also been used to remove metallic ions. For this paper, batch studies were conducted and the uptake of cadmium from water by water hyacinth was investigated for six different concentrations ranging from 0.06–10 mg/L. The daily cadmium uptake for all the concentrations was recorded and the results analyzed. A generalized empirical model and a polynomial model were proposed for the kinetics of cadmium removal. Both models were verified and found to work satisfactorily. Different parts of the plants were also analyzed for cadmium concentration. The cadmium is absorbed by the roots and translocated to different parts of the plants. Maximum cadmium levels were found in the roots of the plants which showed no sign of decay at concentrations as high as 10 mg/L. In addition, the parameters for the continuous operation of a water hyacinth pond were determined.