Sunday, September 29, 2013

Cyclodextrin

Researchers at Temple University's Water and Environmental Technology (WET) Center have been investigating the use of cyclodextrins in the treatment of waste water.
Cyclodextrins are made up of sugar molecules, bonded together to form a ring. An example of the structure of a cyclodextrin, alpha-cyclodextrin which is a 6-membered sugar ring, is shown below:
Cyclodextrins can be used in water treatment because they can bond to substances such as toxic organic compounds or heavy metals and hold them inside the ring structure. Owing to the many polar OH functional groups, cyclodextrins are water soluble, but the researchers have produced insoluble materials by coating a thin layer of cyclodextrin on sand, glass, silica and filter paper. Doing this allows the absorbent material to be collected, washed and re-used.

Reference:
Temple University (2013, September 24). New adsorbent is more effective and environmentally friendly for treating wastewater. ScienceDaily. Retrieved September 30, 2013, from http://www.sciencedaily.com­ /releases/2013/09/130924174152.htm

Further Reading
Carbohydrates: http://ausetute.com.au/members/sugars.html 
Functional Groups: http://ausetute.com.au/fungroup.html
Solubility: http://ausetute.com.au/intermof.html

Zeolites: http://ausetute.com.au/members/zeolites.html
Polymers: http://ausetute.com.au/members/polymers.html 

Suggested Study Questions:
  1. What does the "cyclo" part of the name in cyclodextrin refer to?
  2. Use the structure above to determine the molecular formula for alpha-cyclodextrin.
  3. Use the molecular formula to determine the empirical formula for alpha-cyclodextrin.
  4. Calculate the percentage composition of alpha-cyclodextrin.
  5. Draw the structure of alpha-cyclodextrin and locate and identify the functional groups.
  6. Use a diagram to explain how alpha-cyclodextrin dissolves in water.
  7. Use a diagram to explain how alpha-cyclodextrin could be used to remove lead ions from water.
  8. Draw the structure of alpha-cyclodextrin an clearly identify all 6 of the sugar molecules making up the structure. 
  9. Activated carbon is commonly used to remove contaminants from water. What benefits do you think there might be in using cyclodextrin-derived absorbant materials instead of activated carbon? 

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