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Quantification of Humic and Fulvic Acids in Humate Ores, DOC, Humified Materials and Humic Substance-Containing Commercial Products
Published on: March 18, 2022
Humic acid-cetyltrimethylammonium bromide interaction: a fluorimetric study
Deepa Subbiah1, Ashok Kumar Mishra
1Department of Chemistry, Indian Institute of Technology, Madras, India.
Luminescence : the Journal of Biological and Chemical Luminescence
|September 13, 2008
Summary
Humic acid-surfactant interactions were studied using fluorescence. Cetyltrimethylammonium bromide (CTAB) induced humic acid flocculation, detectable by fluorescence intensity changes.
Area of Science:
- Environmental Chemistry
- Analytical Chemistry
Background:
- Humic substances are complex natural organic matter.
- Understanding their interactions with surfactants is crucial for environmental applications.
- Fluorescence spectroscopy offers a sensitive method for characterizing these interactions.
Purpose of the Study:
- To investigate the interaction between humic acid (HA) and cationic surfactants using fluorescence spectroscopy.
- To determine the effect of humic acid-surfactant composition on flocculation.
- To establish a fluorescence-based method for assessing the physical state of humic acid.
Main Methods:
- Synchronous and excitation-emission matrix fluorescence (EEMF) spectroscopy were employed.
- Humic acid (HA) was interacted with cetyltrimethylammonium bromide (CTAB), sodium dodecylsulphate (SDS), and TX-100.
- Spectral maxima, intensities, and co-precipitation were analyzed.
Main Results:
- HA-CTAB composition variations indicated the extent of HA flocculation.
- Co-precipitation of HA-CTAB occurred within a similar concentration range across studied HA concentrations.
- EEMF maxima at 460/540 nm suggested the presence of ligneous materials in HA.
- No significant interaction was observed between HA and SDS or TX-100.
Conclusions:
- Fluorescence intensity measurement at 460/540 nm is a sensitive method for studying HA's physical state with cationic surfactants.
- Cationic surfactants like CTAB induce HA flocculation, which can be monitored by fluorescence.
- Non-ionic and anionic surfactants showed minimal interaction with humic acid under the studied conditions.
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