Mechanics behind an electrostatic precipitator

[sgstudent]

I understand that there are many different kinds of electrostatic precipiators but I'm referring to the type where a negatively charged wires are placed in between two grounded plate. This essentially makes it a positive plate. So when the smoke rises up they are ionized and thus the ions are attracted to their respective plates/rods. However, the part I'm confused about is whether they are able to accept electrons or give them up when they reach the plate/wires. Meaning do the electrons from the negatively charged wires get given up to the ions and they form molecules again while for the grounded plates do electrons flow into the plate and get grounded and form molecules too? Thanks for the help!

 

[sgstudent]

Also for other electrostatic precipitators they say that when the dust pass through the negative wires they gain a negative charge. How does this happen? Thanks for the help guys!

 

[Bobbywhy]

"The most basic precipitator contains a row of thin vertical wires, and followed by a stack of large flat metal plates oriented vertically, with the plates typically spaced about 1 cm to 18 cm apart, depending on the application. The air or gas stream flows horizontally through the spaces between the wires, and then passes through the stack of plates.

A negative voltage of several thousand volts is applied between wire and plate. If the applied voltage is high enough an electric (corona) discharge ionizes the gas around the electrodes. Negative ions flow to the plates and charge the gas-flow particles.
The ionized particles, following the negative electric field created by the power supply, move to the grounded plates.

Particles build up on the collection plates and form a layer. The layer does not collapse, thanks to electrostatic pressure (given from layer resistivity, electric field, and current flowing in the collected layer)."
http://en.wikipedia.org/wiki/Electrostatic_precipitator

For an excellent technical paper with all the mathematics describing the process in pdf format: www.unc.edu/courses/2009spring/envr/754/001/ESPs.pdf

 

[sgstudent]

But do electrons flow from/to the ions that are stuck on it? Thanks for the help!