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Although
troublesome amounts of alkalinity can be removed in
several ways, none of these methods are normally
satisfactory for household needs. These include:
An
anion resin regenerated with sodium chloride does the
job. This process removes substantially all the anions
(carbonates, bicarbonates and sulfates). It replaces
these anions with a chemically equivalent amount of
chloride ions. The disadvantage of this process is that
in almost all cases a high chloride ion concentration
results. For household purposes such result are almost
as undesirable as the original alkalinity.
The
feed of a mineral acid will neutralize the alkalinity of
water, Hydrochloric acid, sulfuric acid or a combination
of these can be used. This process converts the
bicarbonates and carbonates present into carbonic acid.
At this point it is advisable to provide some method to
permit the gas to escape into the atmosphere.
The
disadvantages of this acid feed technique are obvious.
There are needs for precise control of the process and
caution in handling the strong acid.
Distillation
and demineralization are omitted here, as they are not
normally suitable for home needs.
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