The ability of bone char to remove three single-component metals (namely, c
admium, copper and zinc) from aqueous solutions has been studied. Equilibri
um isotherms have been measured and analyzed using a Langmuir isotherm mode
l. A series of batch contact time experiments were performed to study the e
ffect of sorbent mass and initial metal ion concentration for the three sys
tems. A new film-pore diffusion model has been applied to the batch contact
time results, and good correlation is obtained between theoretical predict
ions and experimental data. A further extension to the new model was made t
o include a surface diffusion term. The agreement between theoretical resul
ts and experimental data improved as the sum of the squares of the errors (
SSE) improved by around 20% for cadmium and zinc but by 50% for copper. The
refore, the sorptions of cadmium and zinc ions onto bone char are primarily
film-pore diffusion controlled, but for the copper system film-pore-surfac
e diffusion must be considered.