PHENOL REMOVAL BY EICHHORNIA-CRASSIPES IN THE PRESENCE OF TRACE-METALS

The removal of phenols in the presence of copper and zinc by the aquatic weed, Eichhornia crassipes was investigated in order to assess its ability to clean up industrial wastewaters. Results indicate that Eichhornia has tremendous capacity to absorb phenolic compounds as well as Cu and Zn simultaneously from test solutions containing these substances. The presence of Cu or Zn resulted in decreased phenol uptake during the first 0.5 d, while the presence of Cu and Zn in combination resulted in higher phenol uptake. After 1 d exposure, however, little or no differences could be discerned. Similarly, absorption of Cu and Zn in the presence of phenols did not seem to be adversely affected by different combinations of Cu/Zn concentrations. In fact, some synergistic effect could be detected between Cu and Zn absorption by Eichhornia crassipes. Bioassays involving filtered Eichhornia root extract indicated that phenol was also removed by the aqueous root extracts indicating that cellular constituents of roots were involved in the process. The corresponding K-m and V-max for the enzyme-like substance were 0.58 and 8.97 mM phenol/h/g fresh root tissue, respectively.