Analysis by the Oxalic Acid Method

The point of zero zeta potential or point of zero charge of Mn dioxides To establish the optimum pH conditions for studying the adsorption of cations or anions on a manganese dioxide, the PZZ and/or PZC of the powder has to be determined. Cations are adsorbed at pH s above these points and anions at pH s below them. 

Select by sedimentation a size fraction of your preparation fine enough not to settle under gravity in a cylindrical cell. Use 0.001 M KNO3 as supporting electrolyte. Plot the electrophoretic mobility (or the zeta potential) against pH and hence find PZZ. Follow the instructions in Sec.2.1.4. 

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