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                                                                                                                   Molecular Spectroscopy Project:

FLUORESCENT WHITENING AGENTS
IN LAUNDRY DETERGENT & PAPER

1: History        2:Importance and Usage        3: Spectroscopy        4: Current Studies        5: Future Expts.

6: HS Classroom Lesson:        A: Lesson Plan        B: Worksheets        C: Instructor Guide
4. Current Studies

 A. Invention/ patenting of cheaper, new FWAs.
    Since Fluorescent whitening agents (FWAs) are used so widely, those that have long been in use are depleted or become increasingly expensive as demand grows.  One study cited that 80% of the raw materials for diaminostilbene (DAST)-based brightening agents (often used in paper) came from China, which increased the price of raw materials and had closed one of its largest producers of DAST in 2007 (1).  Another study cited that there was a 250% global cost increase for FWAs in 2008 (2).  Consequently, there has been much research into finding or creating novel or less expensive FWAs (3-5).  There is also research in improving FWA retention and the processes involved in manufacturing and using FWAs (6).  Predicting how substituents affect the quality of fluorescence, however, still seems to be something of a trial and error process guided by human intuition and very specialized expertise.
The cost of FWAs increased by 250% in 2008.

B. Use as a tracer of anthropogenic wastewater

Figure 1. A cotton pad fluoresces as a result of absorbing
FWAs from streamwater (11).
glowing sample    Because FWAs have become an integral ingredient in laundry detergents.  Several studies have used FWAs as a tracer for human wastewater (7-9).  Since laundry effluent and sanitary wastewater are often mixed together, FWAs can be ued to approximate the source of untreated runoff (8), or even be used to ascertain what percentage of fecal coliform bacteria in a water sample may come from human sources (9).  Since classic fluorimeters are sensitive to the presence of sediments in the sample cell because of the inevitable light absorption and scattering, there is also related research on using LEDs to create a fluorimeter that would be more resistant to the impact of sediments (10).  Figure 1 to the left shows the difference (under a blacklight) between a cotton pad untreated with FWAs and a cotton pad that had been placed in a waterway which contains some domestic runoff. 






    The next section explores the direction of future research into FWAs.

WORKS CITED:
  1. Jackson, A. (2008). The OBA crisis. Pulp & Paper International, 50(10), 56.
  2. Smith, C.D. (2008). Keeping it bright. Pulp & Paper International, 50(9), 18-19.
  3. Christie, R.M., Morgan,K.M., & Islam, M.S. (2008). Molecular design and synthesis of N-arylsulfonated coumarin fluorescent dyes and their application to textiles. Dyes & Pigments, 76(3), 741-747.
  4. Um, S-I. (2007).  The synthesis and properties of benzoxazole fluorescent brighteners for application to polyester fibers.  Dyes & Pigments, 75(1), 185-188.
  5. Um, S-I., Lee, J-K., Kang, Y., & Baek, D-J. (2006). The synthesis and properties of triazine-stilbene fluorescent brighteners containing the phenolic antioxidant. Dyes & Pigments, 70(2), 84-90.
  6. Zhang, H., Hu, H., He, Z., Ni, Y., & Zhou, Y. (2007). Retention of optical brightening agents (OBA) and their brightening efficiency on HYP-containing paper sheets. Journal of Wood Chemistry and Technology, 27, 153-167.
  7. Hayakawa, K., et al. (2007). Distribution and fluxes of fluorescent whitening agents discharged from domestic wastewater into small riers with seasonal changes of flow rates. Limnology, 8(3), 251-259.
  8. Iyer, S., Barbachem, M., McLaughlin, S., & Johnston, W., (2006). Monitoring optical brighteners helps track watershed pollution. Waterworld, December 2006.  http://ww.pennnet.com/display_article/280471/41/ARTCL/none/none/Monitoring-Optical-Brighteners-Helps-Track-Watershed-Pollution/ (January 7, 2009).
  9. Glickstein, N. (2006). Optical brighteners in laundry detergents help us determine the source of bacterial contamination. The American Biology Teacher, 68(5), 296-298.
  10. Morel, L., Speck, P., & Desevauz, P. (2000). A low-cost LED system for fluorescent dye detection. Instrumentation Science & Technology, 28(3), 253-257.
  11. Image of treated and untreated cotton pad. http://ww.pennnet.com/display_article/280471/41/ARTCL/none/none/Monitoring-Optical-Brighteners-Helps-Track-Watershed-Pollution/ (January 7, 2009).