Behavior of Crastrotrea Gaser Biomas And The Rate Controlling Mechanism Of Adsorption Process

Abstract

The potentials of modified and unmodified shells of Crastrotrea Gaser to remove Hg(II), Pb(II), Cd(II) and Cr(III) from aqueous solutions have been investigated in this project. The amount of metal ion adsorbed from solution by these materials at equilibrium is found to depend on agitation time, Results obtained showed that chemical modification blocked some of the adsorption sites therefore, does not improve absorptivity. The percentage of the metal ions removed increases faster as agitation time increases from 1 – 20 minutes until equilibrium was attained at 20 – 40 minutes and decreased to a lower value at 45 – 60 minutes for all the metal ions studied. The level of metal ion uptake from solution follows the trend Hg(II) > Pb(II) Cd(II) > Cr(III) at equilibrium sorption. Different kinetics models were used to characterize the metal ion transport mechanism. The Pseudo-second order was found to best correlate the experimental data, best fit with R2 values ranging from 0.9998 to 1.000 and average value of 0.9999.