Cu(II) Removal from Aqueous Medium Using Blast Furnace Slag (BFS) as an Effective Adsorbent

The copper adsorption by blast furnace slag (BFS) in an aqueous medium was considered based on the influencing parameters, namely the agitation speed, pH, temperature, the particle size of the solid, and the initial concentration. Physicochemical studies have shown that BFS is consisted mainly from SiO2, CaO, Al2O3, and MgO with a specific surface area of 238 m2/g. Under the optimum parameters, the maximum adsorption amount at equilibrium (140 min) corresponds to 45.16 mg/g. Exploration of adsorption isotherms revealed that the Langmuir model is more consistent with the experimental data. The values of the Freundlich (n) and Langmuir (RL) parameters indicate that the adsorption is favorable. On the other hand, the values of Temkin (bt) and Redlich-Peterson (g) parameters show that adsorption is physical. Pseudo-second order of the adsorption process was confirmed using a kinetic study. Moreover, the diffusional study specified that the transfer of copper from the solution to BFS is successively controlled by external and intraparticle diffusion. The thermodynamic parameters showed that the adsorption of Cu(II) on BFS was feasible, spontaneous, exothermic, and less entropic. The desorption phenomenon has revealed that BFS can be reused for three consecutive cycles.