Development of novel blend membranes based on carbohydrate polymers for the removal of toxic metal ions through sorption

<p>The present study describes the development of novel sodium alginate–gelatin (SAG) blend membranes for the removal of copper(II) and nickel(II) ions from aqueous solutions through sorption. The SAG blend membranes were chemically crosslinked by various crosslinkers, such as glutaraldehyde (GA), urea-formaldehyde (UF) and thiourea-formaldehyde (TF) in order to enhance the strength of the membranes and reduce their swelling behaviour in presence of water. The resulting membranes were extensively characterized by FTIR, SEM and DSC to study various structural aspects of the membranes. Equilibrium swelling experiments were performed on SAG membranes in metal ion solutions at 30°C. The effect of contact time, initial pH and initial metal ion concentration on the sorption behaviour of the membranes was investigated. The adsorption capacities of copper(II) and nickel(II) on the SAG (SAG-GA/UF/TF) membranes as obtained from Langmuir adsorption isotherm were found to be 0.4284, 0.5307, 0.6847 mM/g and 1.7567, 3.3329, 4.1 mM/g, respectively.</p

Fabrication of Polyelectrolyte Membranes of Pectin Graft-Copolymers with PVA and Their Composites with Phosphomolybdic Acid for Drug Delivery, Toxic Metal Ion Removal, and Fuel Cell Applications

In this study, a simple method for the fabrication of highly diffusive, adsorptive and conductive eco-friendly polyelectrolyte membranes (PEMs) with sulfonate functionalized pectin and poly(vinyl alcohol)(PVA) was established. The graft-copolymers were synthesized by employing the use of potassium persulfate as a free radical initiator from pectin (PC), a carbohydrate polymer with 2-acrylamido-2-methyl-1-propanesulphonic acid (AMPS) and sodium 4-vinylbenzene sulphonate (SVBS). The PEMs were fabricated from the blends of pectin graft-copolymers (PC-g-AMPS and PC-g-SVBS) and PVA by using a solution casting method, followed by chemical crosslinking with glutaraldehyde. The composite PEMs were fabricated by mixing phosphomolybdic acid with the aforementioned blends. The PEMs were successfully characterized by FTIR, XRD, SEM, and EDAX studies. They were assessed for the controlled release of an anti-cancer drug (5-fluorouracil) and the removal of toxic metal ions (Cu2+) from aqueous media. Furthermore, the composite PEMs were evaluated for fuel cell application. The 5-fluorouracil release capacity of the PEMs was found to be 93% and 99.1% at 300 min in a phosphate buffer solution (pH = 7.4). The highest Cu2+ removal was observed at 206.7 and 190.1 mg/g. The phosphomolybdic acid-embedded PEMs showed superior methanol permeability, i.e., 6.83 × 10−5, and 5.94 × 10−5, compared to the pristine PEMs. Furthermore, the same trend was observed for the proton conductivities, i.e., 13.77 × 10−3, and 18.6 × 10−3 S/cm at 30 °C