Enhanced adsorption of Pb(II) by Al(OH)3/(PAA-CO-PAM) sub-microspheres with three-dimensional interpenetrating network structure

• Al(OH)3/(PAA-CO-PAM) sub-microspheres with three-dimensional interpenetrating network structure were synthesized.
• The maximum adsorption capacity was 106.2 mg/g within 150 min.
• Adsorption behavior for Pb(II) onto sub-microspheres belongs to the pseudo-second-order kinetic model.
• Thermodynamic parameters indicated the adsorption process was spontaneous, endothermic and feasible.

Al(OH)3/(PAA-CO-PAM) sub-microspheres have been synthesized via inverse emulsion polymerization method using 0.0132 g (NH4)2S2O8 as initiator, 2.2 g each of acrylamide aluminum acrylate as monomers, 1.5 g Span-80 and 0.5 g polyoxyethylene octylphenol ether (OP-10) as emulsifiers at 66 °C for 10 h. The composition and morphology of the obtained Al(OH)3/(PAA-CO-PAM) sub-microspheres were investigated by infrared spectrum, X-ray powder diffraction (XRD) and scanning electron microscopy. The obtained Al(OH)3/(PAA-CO-PAM) sub-microspheres were used to investigate adsorption of Pb(II) from aqueous solutions. The research results display that composite material has high adsorption capacity for Pb(II) at an optimum pH 5. The maximum adsorption capacity was 106.2 mg/g within 240 min at 24 °C. Various thermodynamic parameters such as free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) showed that the adsorption was spontaneous, endothermic and feasible. Adsorption behavior for Pb(II) onto sub-microspheres belongs to the pseudo-second-order kinetic model and the adsorption process is a chemical process.