Supplementary Material

for

Use of fourier transform infrared spectroscopy to examine the Fe(II)-catalyzed transformation of ferrihydrite

Wei Xiao, Adele M Jones, Richard N Collins, Mark Bligh and T. David Waite*

UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052, Australia

Talanta

Corresponding author: Tel: +61 2 9385 5060; Fax: +61 2 9385 6139; Email: d.waite@unsw.edu.au

Figure S1. FTIR absorbance spectrum of aggregated nanogoethite (ag. nGt) and aggregated micro-goethite (ag. Gt) suspensions compared to unaggregated suspensions. Aggeagation was achieved by allowing the particles to settle in an unmixed suspension of 10 mM sodium bicarbonate and 0.1 M sodium chloride adjusted to pH 7.0 over a period of 24 hours.

Figure S2. FTIR absorbance spectra (baseline corrected) of all experimental samples analyzed and displayed in Fig. 6.

Figure S3. FTIR absorbance spectrum of a 3 µL aliquot of 10 mM lactate dried on the 3 mm FTIR crystal plate.

Figure S4. FTIR absorbance spectrum of a 3 µL aliquot of 50 mM TEED buffer dried on the 3 mm FTIR crystal.

Figure S5 – FTIR absorbance spectra (baseline uncorrected) of a concentrated cell culture and a range of Fe oxide reference materials.

00.10.20.30.40.50.6500600700800900100011001200IR Absorbance Intensity (a.u)Wavenumber (cm

-1

)

FerrihydriteGoethiteLepidocrociteConcentrated cell culture

00.10.20.30.40.50.6500600700800900100011001200Absorbance IntensityWavenumber (cm

-1

)

nGtag nGtGtag Gt

(c) 10 Fh+0.5 Fe

II

(a)5 Fh+ 0.5 Fe

II

(b) 5 Fh+ 1 Fe

II

(d) 10 Fh+ 1 Fe

II

(e) 10 Fh+ 1 lact+ 1 Fe

II

(f) 10 Fh+ 5 lact+ 1 Fe

II

(g) Bio 5 Fh(h) Bio 10 Fh

0.000.050.100.150.200.250.300.35500600700800900100011001200IR Absorbance Intensity (a.u)Wavenumber (cm-1)

00.050.10.150.20.25500600700800900100011001200Absorbance IntensityWavenumber (cm

-1

)