The most common form of brines is sodium chloride (NaCl)-based. These are used primarily in the production of chlorine gas (Cl2) via electrolysis and the polymeric membrane cell process, in which brines are passed through an ion-exchange membrane, where the brine is de-chlorinated via electrolysis to produce chlorine gas. This is the most widely used means of producing Cl2 because the membrane cell process consumes the least amount of energy compared to other Cl2 production processes.
The membrane must remain clean, as contamination will poison it. And since replacing the membrane is expensive, it should only be changed when needed – this can be defined by monitoring the elemental concentrations in the brine, particularly elements which can poison the membrane: aluminum, barium, calcium, iron, magnesium, nickel, silicon, and strontium. These elements should be present at less than 0.1 mg/L in the brine, meaning that low concentrations have to be measured accurately.
Brine analysis presents a challenge due to the extremely high levels of total dissolved solids and the low analyte levels. And because of its ability to handle high levels of dissolved solids, ICP-OES is the preferred analytical technique for brine analysis.
This work demonstrates the ability of PerkinElmer’s Avio 200 hybrid-scanning ICP-OES to accurately measure important contaminants at low levels in brines.