Effect of Some Factors on Biosorption of Lead by Dried Leaves of Water Hyacinth ( Eichhornia Crassipes )

Biosorption and removing some heavy metals such as Cd, Pb, Zn and Cr from the aqueous solutions by dried leaves of wa ter hyacinth was investigated, and effect of pH, contact time and ad sorpent dose on biosorption also studied. The results revealed the ability of w ater hyacinth to remove heavy metals from the aqueous solutions but there was a d istinctive variations in biosorpency. Lead was the most adsorbed among other metals, where 58% of Pb were removed. The results showed in the pH of 5,120 min of contact time and 3 gram of adsorbent dose, the maximum removing of Pb was 91%. Biosorption by the dried leaves of water hyacinth is technique can be used for removal metal pollutants from water.