Purifying and Purifying and Softening WaterSoftening Water

L.O: L.O: To know how to soften and purify hard water, and the pros and cons associated with this

Calgon – water Calgon – water softenersoftener

http://www.youtube.com/watch?v=NIfayRbEPDI

Try adding sodium carbonate to Try adding sodium carbonate to hard water what happens to the hard water what happens to the amount of soap needed?amount of soap needed?

Water Softeners Water Softeners

Water can be softened using sodium carbonate. It immediately precipitates the calcium and magnesium

calcium ions + Sodium carbonate

calcium carbonate + sodium ions

Ca+ + Na2CO3 CaCO3 + 2Na+

Ion Exchange softeners

The sodium ions (or sometimes hydrogen) are used to replace calcium and magnesium ions in the water.

Carbon and silver are sometimes used to make ion exchange resins

Calgons chemical name is sodium metaphosphate, it works in the same way as sodium carbonate

Softening hard waterSoftening hard water

Explain how an ion exchange Explain how an ion exchange softener workssoftener works

Toxic Chemicals in Toxic Chemicals in Water Water

Copper and lead from Copper and lead from mining mining

Nitrates from fertilisers Nitrates from fertilisers can cause ‘blue baby can cause ‘blue baby syndrome’, the layman’s syndrome’, the layman’s term for baby’s with term for baby’s with cyanotic conditions. cyanotic conditions.

How are things like this How are things like this removed?removed?

Most water although removed of salt is not suitable for drinking and must be purified

first

1) Sieve to remove large objects

3) Clear water has chlorine added to it

2) Sand is used to filter fine objects

Stages in water Stages in water treatmenttreatment