Question

Using chemical reactions explain how ion exchange chromatography help in ecological remediation and state the equations involved

Answer 1

Ion exchange chromatography is a method of purifying substances through exchange of ions. For instance, in water treatment, one or more ionic contaminants can be eliminated from water through exchange with another non-objectionable ionic compound.

Ion exchange chromatography helps in softening water by removing Magnesium and calcium ions.

When treating water, $Ca(OH)_2$ and $Na_2CO_3$ are used. $OH^-$ ions produced reacts with $Mg^{2+}$ ions to form insoluble precipitate $Mg(OH)_2$ (easily removed).

$Ca^{2+}$ are then removed by separate reaction with $CO^{2-}_3$ from $Na_2CO_3$

$Mg^{2+}_{aq}+20H^-_{aq} \to Mg(OH)_2 (s)$