Thursday, January 12, 2012

How do you extract lignin from peanut shells?

I have been searching the library and the net but i think no one really cares about peanut shells and how to take lignin out of them... If I'd ask chemistry smart people, they say you need to buy a book about paper making but I've traveled the whole city looking for one but i cant find one... Please i need a concrete answer by Wednesday... :'(

How do you extract lignin from peanut shells?
hi! this is now my edited answer. since it is important for you to collect as much lignin as you want, you can increase the amount of the sample but maintaining the necessary proportion and concentration of H2SO4 might be necessary.



1. grind or pulverize the peanut shells first. i use a miller for grinding and a standard 40 mesh screen to collect the powder.

2. oven dry the material overnight (105C).

3. in a 100 ml beaker, treat 1g sample with 15 ml of 72% sulfuric acid and set aside for 2 hours. stir occasionally. do this at room temp. (sample turns black)

4. transfer the treated sample in a 1L Erlenmeyer flask and add 560 ml distilled water to make a 3% concentration.

5. gently boil for 2 hours. cover the flask with a small beaker or a reflux condenser if available. (lignin is extracted as a precipitate)

6. vacuum filter using a preweighed glass filter of medium porosity to collect the precipitated lignin.

7. oven dry.

8. compute for % lignin component:

_g lignin/ g sample* 100%



the lignin is brownish black in color.

good luck!
Reply:Lignin is the protein contained in wood fibers. It is extracted from wood pulp using sodium hydroxide. This makes the lignin soluable and this separates the wood fibers. The fibers are then neutralized and bleached to make paper. The lignin solution is known as "black liquor" and must be neutralized with acid before it can be disposed of. I suspect sulfuric acid is used, since the sodium sulfate produced is somewhat insoluable and will precipitate out of the solution if the proper amount is added. The formula is:



2NaOH + H2SO4 -%26gt; Na2SO4 + 2H2O



One can probably achieve acceptably good neutrality by adding equal weights of sulfuric acid and lye. Of course, both chemicals are very corrosive and heat up when water is added, so they must be used with caution.
Reply:Jack Bauer would break their fingers until they surrender the lignin.


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