How use ferrite bead to reducing noise from charge pump?
A ferrite bead on a conductor creates a very small inductor. The inductance is a function of the size of the bead, the ferrite material used and the number of turns through the bead.

It is extremely unlikely that the ferrite bead will be able to filter switching frequency - they tend to be used to suppress noise well up into the megahertz. I doubt that it will have any effect on ripple (usually tens or hundreds of kilohertz) - it is quieting high-frequency spikes (megahertz and higher) which may be disturbing digital circuits or generating EMI. 

Sizing an LC filter for this sort of noise reduction involves measuring the frequency and amplitude of the noise you're trying to suppress. The type of ferrite material as well as the type and value of the capacitor is critical for HF suppression. Once you know the noise you need to quiet, and the characteristics of the LC filter, you can determine how much attenuation you will have .

It can be difficult to design these HF LC filters up-front without knowing what sort of noise you're dealing with. Often, you'll put footprints in the PCB layout for the LC and empirically determine what values you actually need once you get the hardware running.