Synthesis and characterization of bulk functionalized polyurethane foams for lead ion

removal from water at ppb levels

Cristian BonillaSubhashini Gunashekar

Dr. Nidal Abu-Zahra

OBJECTIVE

Preparing a bulk functionalized polyurethane foam containing sulphonic acid groups as ion exchange media to remove Pb2+ from water.

Determining the main physical properties of the foam and chemical structure through a detailed characterization.

MOTIVATION

Lead is a toxic heavy metal that is harmful to human health.

The occurrence of lead in drinking water is mainly from corrosion of lead pipes and solders and faucets made with leaded brass, especially in areas of soft and acidic water.

Long-term exposure is toxic and high levels of lead contamination in a child can result in convulsions, major neurological damage, organ failure, coma, and ultimately death.

POLYURETHANE FOAM SYNTHESIS

Experimental set up – Raw materials reacted at 70oC in a nitrogen atmosphere

Prepolymer containing functionalized groups capable

of removing lead ions

Addition of blowing agent to initiate foaming

Foaming Pre-polymer Cast Open cell Polyurethane Foam

RESULTS

a. b. c.

d. e. f.

(a) FTIR spectrum of samples A1-A4

(b) FTIR spectrum of samples B7-C10

(c)High and low molecular weight compounds on the samples based on BES/DMSO content

(d)EDX elemental analysis(e)SEM image of

polyurethane foam at 50X magnification

(f) Lead removal efficiency based on BES/DMSO molar content

RESULTS (cont.)

(g) Lead removal efficiency based on PPG/TDI molar content

(h) Lead removal efficiency with variable CERT

Foam Foam Foam

1st Run 2nd Run 3rd Run

PH AND MULTISTAGE BATCH ANALYSIS

g. h.

i.

j. k.

(i) Multistage batch filtration process set-up(j) Lead removal capacity from multistage filtration process(k) pH analysis of functionalized polyurethane foam

CONCLUSION

The foam with the molar composition of 1 mole of PPG, 2 moles of TDI, 0,6 moles of BES, and 4 moles of DMSO with a CERT of 40 min seemed to be the most stable structurally and had the highest Pb2+ removal efficiency of 47ppb/g for 1 h exposure in 100 ppb Pb2+ solution.

Higher amounts of foam samples in a multistage batch filtration set up increased the Pb2+ removal efficiency.

The functionalized polyurethane foam performed better at lower pH levels, after exposure times of two hours.