Hello,
I am currently doing some fouling experiments where the foulant is composed of polysaccharides and proteins and I would like to 'properly' compare both spectra. I thought about taking a characteristic peak of the membrane but the membrane background is relally small after fouling (probably due to the thickness of the fouling layer).
Is there any standard method or is it up to the researcher in that case?
Hi Cyril,
Is your spectrum measured in "Absorbance" or "Transmittance" units?
I would recommend using other complementary methods to assess the fouling extent of your membrane (e.g. contact angle measurements, AFM)
Best wishes,
Maguy
Hello Maguy,
Thanks for your advice. I did not think about Contact Angle but it could be interesting to use it to characterise the fouled membrane.
To analyze the fouling layer onto the surface of the membrane, I use ATR-FTIR spectroscopy in Absorbance mode. I intended to manually apply similar pressure for both acquisitions but this is more a "feeling" than a rigorous approach to compare spectra.
I have attached an example of one of my tests where information on the fouling composition can be extracted (Protein - Amide I & II + Carbonyl bands).
Cheers,
Cyril
Hi Cyril,
If the measurements were collected by the ATR sampling (i.e. ATR-FTIR) technique, then I would not recommend doing quantitative analysis of the absorbance measurements due to the limited analytical depth of the evanescence phenomenon compared to the transmission method.
I think that comparison of spectra clearly show fouling by proteins i.e., Amide I (~1600-1650 cm-1) and Amide II (~1500-1575 cm-1). In addition, peak at ~1032 cm-1 shows the carbonyl in polysaccharides. The fouling layer seems to be very thick, which the reason the absorbance of the characteristic peaks of fouled PVDF membrane reduced significantly. I hope that it will help.
Cheers,
Bilal
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