What is use of point of zero charge of any adsorbent? How can we use that value to support the results of experiment?

I did a point of zero charge  experiment to my adsorbent (bael shell activated carbon ) and got 6.25,but  I got maximum removal of Pb(II) at pH 4. Can anyone explain how we can interlink these...

08 June 2015 9,226 17 View