Air pollution control and flue gas desulfurization residues from Polish copper smelting facility as adsorbents of Pb(II) and Cu(II) from aqueous solutions.

This study aimed at evaluation of air pollution control residues (APCR) and flue gas desulfurization residues (FGDR) from copper foundry in Southwestern Poland as adsorbents of Cu(II) and Pb(II) from simulated wastewater. Studies of the impact of pH and adsorbent dose, as well as sorption isotherms, and kinetic and thermodynamic studies were conducted in a series of batch experiments. The maximum adsorption capacities were equal to 42.9 mg g-1 Cu(II) and 124.4 mg g-1 Pb(II) for APCR and 98.8 mg g-1 Cu(II) and 124.7 mg g-1 Pb(II) for FGDR, which was comparable to mineral adsorbents examined in other studies. Adsorption isotherms followed the Langmuir model, except for Pb(II) for FGDR, which followed Freundlich model. Sorption kinetics for both materials was properly expressed by pseudo-second-order equation. Mean adsorption energy parameter suggested that the adsorption might have occurred via physical bonding. Thermodynamic study revealed that adsorption was spontaneous and endothermic for Cu(II) and not spontaneous and exothermic for Pb(II), with lower temperature favoring the process. The results suggested that both materials had high affinity towards Cu(II) and Pb(II) ions and could be conducted industrial scale research for consideration as potential adsorbents from aqueous solutions.