Ion Exchange Process

Ions

These are atoms or molecules containing a total number of electrons that are not equal to the total number of protons.

Cations

These are positively charged ions.

Anions

These are negatively charged ions.

Ion exchange

It is a water treatment process commonly used for water softening.

Polystyrene-divinylbenzene (SDVB)

Ion exchange is based upon _____ which is stable up to 150 degrees C, has a pH of 0 to 14, and is very resistant to oxidizing conditions.

Hydrogen

In a sodium and hydrogen cation exchange, what is used as a cation substitute to Ca and Mg ions?

810 kg of CaCO3 / m³ ion exchanger

The total exchange capacity of a Na-cycle cation is ____.

925 kg of CaCO3 / m³ ion exchanger

The total exchange capacity of a H+ cycle cation is ____.

True

TRUE OR FALSE. The calcium and magnesium ions are exchanged for sodium ions in a sodium and hydrogen cation exchange.

Regeneration

This happens when each of the individual exchange sites will become full with prolonged use and when it is unable to exchange ions any longer.

Solution of common salt (NaCl)

What can be used to regenerate sodium-cation?

Sulfuric acid

What can be used to regenerate hydrogen-cation?

Caustic soda

What can be used to regenerate highly basic anion exchangers?

Caustic soda, soda ash, or ammonium hydroxide

What can be used to regenerate weakly basic anion exchangers?

Leakage

It refers to small amounts of hardness that are present in the treated water.

True

TRUE OR FALSE. The hardness leakage level depends on the hardness and sodium level in the influent water and the amount of salt used for regeneration.

Single tank standby
Series
Parallel
Series Parallel

Enumerate the four (4) types of ion exchange tanks used in an ion exchange process.

Highly basic, weakly basic

Anion exchangers are of two resin types. What are these two?

True

TRUE OR FALSE. Both highly and weakly basic resin types in anion exchangers can remove strongly ionized acids, but only highly basic anion exchangers can remove weakly ionized acids.

4% sodium hydroxide solution

Strong base anion exchangers are regenerated with a _____.