Adsorption of heavy‐metal ions on poly(ethylene imine)‐immobilized poly(methyl methacrylate) microspheres

Abstract

Poly(methyl methacrylate) (PMMA) microspheres carrying poly(ethylene imine) (PEI) were prepared for the removal of heavy-metal ions (copper, cadmium, and lead) from aqueous solutions with different amounts of these ions (50 -600 mg/L) and different pH values (3.0 -7.0). Ester groups in the PMMA structures were converted to imine groups in a reaction with PEI as a metal-chelating ligand in the presence of NaH. The adsorption of heavy-metal ions on the unmodified PMMA microspheres was very low [3.6 mol/g for Cu(II), 4.6 mol/g for Cd(II), and 4.2 mol/g for Pb(II)]. PEI immobilization significantly increased the heavy-metal adsorption [0.224 mmol/g for Cu(II), 0.276 mmol/g for Cd(II), and 0.126 mmol/g for Pb(II)]. The affinity order of adsorption (in moles) was Cd(II) Ͼ Cu(II) Ͼ Pb(II). The adsorption of heavy-metal ions increased with increasing pH and reached a plateau value around pH 5.5. Their adsorption behavior was approximately described with the Langmuir equation.

Preparation and performance of cellulose acetate/polyethyleneimine blend microfiltration membranes and their applications

“…The data were fitted to the single-solute Langmuir isotherm equation by Schatchard plot and the parameters q m and K d are 7.42 mg/g membrane and 1.71 × 10 −4 mol/l, respectively. The maximum capacity of the blend membrane is about 40% of the result of Duru et al [23]. In order to remove heavy metal ion from aquatic system efficiently, it is necessary to improve the content of PEI in resulting membranes.…”

“…The static adsorption of Cu 2+ on blend membranes was carried out by a batchwise method. The membranes (15 mg) were shaken in 5 ml of Cu 2+ solutions for 2 h [23] at 15 • C. The concentrations of copper ion before and after adsorption were measured by JASCO-v550 UV-Vis (Japan) spectrophotometer at 560 nm, using 0.024% solution of 2-[(5-bromo-2-pyridyl)-azo]-5-diethyl aminophenol (5-Br-PADAP, Beijing Hongyu Chemical Engineering Ltd., China) in 95% ethanol aqueous solution as indicator. The amount of Cu 2+ adsorption was calculated from difference between concentrations before and after adsorption.…”

“…Among reactive groups such as hydroxyl group, amine group and sulfhydryl group, amine groups and sulfhydryl groups are much more active than hydroxyl groups and can be much more easily attacked by modifying agents (which provide functional groups) under mild conditions [17,18]. Polyethyleneimine (PEI) is a branched chain polymer with a lot of amine groups and has extensively been used to modify membrane surface [19], effectively complex heavy metal ions [20][21][22][23] and selectively adsorb endotoxins [24] from protein solutions. By different methods of chemical modification, PEI can be immobilized on the surfaces of basic membranes and used as ligands [25][26][27][28] or to supply further coupling sites for immobilization of different ligands [29].…”

Enhancement of Nitrite and Nitrate Electrocatalytic Reduction through the Employment of Self-Assembled Layers of Nickel- and Copper-Substituted Crown-Type Heteropolyanions

“…PEI has been used for the synthesis of the AgNPs 41,42 with the UV-Vis spectrum (Fig. 1SA) revealing the plasma resonance peak at 408 nm, which is typical for the plasmon absorbance of spherical shaped Ag-NPs 43 .…”

Nitrate and Nitrite Electrocatalytic Reduction at Layer-by-Layer Films Composed of Dawson-type Heteropolyanions Mono-substituted with Transitional Metal Ions and Silver Nanoparticles

“…PEI was used for the synthesis and stabilization of the AgNP as it has the ability to chelate a variety of transition metal ions with amine groups [62], especially silver ions [63]. The resulting brown colour of the solution obtained during the AgNP synthesis is evidence of the formation of the AgNP.…”