Structurally Functionalized Polyurethane Foam for Elimination of Lead Ions from Drinking Water

Abstract

Polyurethane foams functionalized with Sulfonic acid groups have been found to be strong cation exchangers. This novel property of the foam was used to exchange lead (Pb 2+ ) ions from aqueous solutions. Polyurethane foam synthesis is based on addition polymerization of the highly reactive isocyanate (-NCO) groups of an isocyanate with the hydroxyl (-OH) groups of a polyol to form the urethane species. Toluene-2,4-2,6-diisocyanate was reacted with Polypropylene glycol 1200 in 2:1 molar ratio to form a linear pre-polymer. The linear pre-polymer was further polymerized using a chain extender, N, N-bis (2-hydorxyethyl)-2-aminoethane-sulfonic acid (BES). BES also acts as a functional group to exchange Pb 2+ ions. A set of experiments were designed to study various process parameters. The functionalized polyurethane foam was characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, scanning electron microscopy, and energy dispersive x-ray spectroscopy. The Pb 2+ ion exchange capacity was determined using an Inductively Coupled Plasma Mass Spectrometer. The maximum Pb 2+ ion exchange capacity of the foam was found to be 47 parts per billion per gram (ppb/g) from a 100 parts per billion (ppb) Pb 2+ solution over a period of 60 minutes. A multistage batch filtration process increased the Pb 2+ ion removal to 50-54 ppb/3g of foam over a period of 90 minutes.

Chromatographic Separation, Total Determination and Chemical Speciation of Mercury in Environmental Water Samples Using 4-(2-Thiazolylazo) Resorcinol-Based Polyurethane Foam Sorbent-Packed Column

“…Commercial PUFs also exhibit poor hydrophobicity to some extent, as required for their practical use for cleanup and recovery of organic (e.g. oil spell) and inorganic species [33][34][35][36][37][38][39]. Hence, surface modification of PUFs is desired to enhance the wettability and hydrophobicity to make it a super hydrophobic and oleophilic absorbent [25][26][27][28][29][30][31][32][33][34].…”

Adsorptive removal of vitamin B6 and ciprofloxacin using polyurethane foam in pure and pharmaceutical preparations: Kinetic and equilibrium studies

“…PUFs are known to have excellent thermal insulation and water-resistant properties. [15][16][17] The available surface area and cellular structures of polyurethane foam make it very suitable for the adsorption of various pollutants. Furthermore, polyurethane foams are capable of maintaining various types of substances due to the inclusion of polar and non-polar groups in their structures.…”

“…18 PUFs have been successfully employed as an effective adsorbent for the removal water pollutants such as the adsorption of methylene blue (MB), 19 removal of organic insecticides, 20 sorption of Co(II)/Zn(II)-thiocyanate complexes, 21,22 and sorption of heavy metal ions (Ag(I), Pb(II), U(VI)). 16,[23][24][25] Vitamin B 6 (Pyridoxin hydrochloride-PDX), which is an important factor to metabolize proteins, has a key role in the maintenance of body cells and participates in the utilization of glycogen and immune function. Furthermore, vitamin B 6 has a major role in the synthesis of heme niacin, neurotransmitters, connective tissues, eicosanoids, and sphingolipids in nerve sheaths are also essential.…”

“…Polyurethane foam (PUF) is one of the most diverse porous Polymeric materials that are produced by the reaction of a Polyol with at least two hydroxyl groups with the two or more isocyanate groups of an isocyanate as shown in Scheme 1c. PUFs are known to have excellent thermal insulation and water‐resistant properties 15–17 . The available surface area and cellular structures of polyurethane foam make it very suitable for the adsorption of various pollutants.…”

“…Polyurethane foams can be used for the uptake of polarizable free molecules such as aromatic compounds, metallic dithizonates or iodine, and large anions with high polarizability 18 . PUFs have been successfully employed as an effective adsorbent for the removal water pollutants such as the adsorption of methylene blue (MB), 19 removal of organic insecticides, 20 sorption of Co(II)/Zn(II)–thiocyanate complexes, 21,22 and sorption of heavy metal ions (Ag(I), Pb(II), U(VI)) 16,23–25 …”