Sorption of Pb(II), Cd(II), and Ni(II) From Single- and Multimetal Solutions by Recycled Waste Porous Glass

Selective sorption of lead, cadmium, and nickel ions on recycled waste porous glass beads was investigated. Single-metal equilibrations were carried out in demineralized water and ternary metal equilibrations were carried out in demi- and tap water. Freundlich isotherm gave a good correlation of the experimental data. Maximum metal retention (q_max) in single-ion solutions were 18.66 mg/g_RPWG (0.090 mmol/g_RPWG), 4.83 mg/g_RPWG (0.043 mmol/g_RPWG), 4.00 mg/g_RPWG (0.068 mmol/g_RPWG), respectively, for Pb⁺², Cd⁺², and Ni⁺², and lower figures were in the case of ternary systems: 13.50 mg/g_RPWG(0.065 mmol/g_RPWG), 2.23 (0.020 mmol/g_RPWG), 2.05 mg/g_RPWG(0.034 mmol/g_RPWG), respectively, for Pb⁺², Cd⁺², and Ni⁺², with further drastic reduction in tap water. Metal exhausted beads were used as thermal insulators in cement mortars, minimizing their potential impact in the environment.