[moon]

   HI!!!!!!!
I have been doing an experiment in which I use the shell of the egg as an adsorbent . What we did was lay the egg shell in the lead-contaminated water. Then we filter it. An the lead was adsorbed by the eggshell
I would like to know what reactions are produced in the contaminated water with the shell egg

[constant thinker]

http://en.wikipedia.org/wiki/Egg_shell

Your egg is made of CaCO₃ (calcium carbonate).

Now try writing a chemical equation based on what you observed so should be able to figure out ballpark what compound was formed.