Abstract: (5679 Views)
In this work, blast furnace slag (BFS) was used as an adsorbent material for the removal of Pb(II) ions in solution in batch mode. The physico-chemical analyzes used indicated that the BFS is essentially composed of silica, lime, and alumina. Its specific surface area corresponds to 275.8m2/g and its PZC is around 3.8.
The adsorption study indicated that the maximum amount of Pb(II) adsorbed under optimum conditions (agitation speed (Vag): 150rpm; pH: 5.4; particle size (Øs): 300µm, T: 20°C) is 34.26mg/g after 50 minutes of agitation, and adsorption yield is best for feeble initial concentrations. The most appropriate isothermal model was that of Langmuir, and the adsorption speed was better characterized by the pseudo-second order kinetic model. The adsorption mechanism revealed that internal diffusion is not the only mechanism that controls the adsorption process; there is also external diffusion, which contributes enormously in the transfer of Pb(II) from solution to adsorbent. Thermodynamic study indicated that the Pb(II) adsorption on the blast furnace slag (BFS) was spontaneous, exothermic, and that the adsorbed Pb(II) is more ordered at the surface of the adsorbent. Finally, we estimate that BFS is a superb adsorbent for water containing Pb(II).
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Highlights:
- The the blast furnace slag (BFS) consists mainly of silica, lime, and alumina. Its specific surface area corresponds to 275.8m2/g and its PZC is around 3.8.
- The maximum adsorption capacity is 34.26 mg/g after 50 minutes,
- The Langmuir model is the most commonly used for this process; the adsorption rate is best described by pseudo-second order kinetics, and lead ion transfer is governed by external and internal diffusion.
- Pb(II) adsorption on BFS is spontaneous, exothermic, and produces less entropy.