The water hydronium ions
can penetrate the glass surface lattice and exchange with mobile ions present in the interstitial positions of the glassy matrix.
Taking into account the fact that 4 hydronium ions
are consumed per AO7 molecule, the change in pH expected on the basis of reaction (2) results to be much less than what observed.
The decrease in lead uptake by acid desorbent might be due to the increase of the concentrations of competing hydronium ions
. It is also possible that the physical structure of the biomass becomes damaged by this acid .
At low pH, the surface of the adsorbent was surrounded by hydronium ions
that compete with metal ions, which prevented the metal ions approaching the binding sites on the adsorbent.
These nitrogen radicals then interact with moisture in the atmosphere to create hydronium ions
A low pH indicates a high concentration of hydronium ions
, while a high pH indicates a low concentration.
The procedure involves spraying water in the presence of an electric field, causing water molecules to become positively charged "hydronium ions
," which contain an extra proton.
No adsorption was observed at low pH values due to opposition of hydronium ions
with the metal ions.
One of the main effects of the medium's pH over the sorption process is related to presence of hydronium ions
which may cause the protonation of the adsorption sites (obviously this process is more evident at low pHs).