Methacryloylamidoglutamic Acid Incorporated Porous Poly(methyl methacrylate) Beads for Heavy-Metal Removal

Abstract

Poly(methyl methacrylate-methacryloylamidoglutamic acid) beads (average diameter 150-200 µm) were prepared by copolymerizing methyl methacrylate (MMA) with methacryloylamidoglutamic acid (MAGA). Poly(MMA-MAGA) beads were characterized by swelling and surface area studies, scanning electron microscopy, and elemental analysis. These porous beads with a swelling ratio of 36.4% and containing 696 µmol of MAGA/g were used for heavy-metal removal involving cadmium, mercury, and lead. Poly(MMA-MAGA) beads have a specific surface area of about 67.8 m 2 /g. Metal adsorption results were found to be a function of solution properties (i.e., medium pH and metal concentration) and the types of metals to be adsorbed. We have obtained adsorption capacities as 29.9 mg/g (149 µmol/g) for Hg(II), 28.2 mg/g (250 µmol/g) for Cd(II), and 65.2 mg/g (314 µmol/g) for Pb(II). The adsorption capacities on an observed molar basis were in the order of Pb(II) > Cd(II) > Hg(II). Adsorption of heavy-metal ions from synthetic wastewater was also studied. The adsorption capacities are 22.4 mg/g for Hg(II), 24.2 mg/g for Cd(II), and 52.6 mg/g for Pb(II) at 0.5 mmol/L initial metal concentration. Of course, depending on the desired goals, the beads containing metal could be regenerated for appropriate disposal. Our results suggest that poly(MMA-MAGA) beads can be good metal adsorbers and have great potential applications in environmental protection.

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“…Isotherms: (11) where C eq (mg/L) and C o (mg/L) were analyte concentrations at equilibrium and at the highest feeding concentration, respectively. Q t (μg/g) and Q eq (μg/g) were adsorption capacities at contact time t and at equilibrium, respectively, whereas Q max (μg/g) was the theoretical maximum adsorption capacity.…”

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