Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry

Copper Sensing in Alkaline Electrolyte Using Anodic Stripping Voltammetry

Joed Ortiz, Timothy N. Lambert and Jonathon Duay 

Anodic stripping voltammetry (ASV) is an analysis technique that permits the selective determination for the concentration of metal ion species in solution.   Applying this method to alkaline electrolytes will allow the determination of the diffusion coefficients of metal ions as they pass through/crossover alkaline battery membranes/separators. Here, an ASV method for determining copper (Cu) concentration in alkaline solutions is developed utilizing lead (Pb) as a deposition mediator. As such, it was found that when using copper in conjunction with lead, the stripping voltammetry curves present separate and defined peaks.  Different analyzes were made to find the conditions for the best stripping voltammetry performance. Accumulation potential, accumulation time, as well as concentrations of Pb, Cu and KOH were performed. Calibration curves with 5 ppm of Pb with an increase of 1 ppm Cu per experiment showed the best stripping signal with a peak area correlation of R2= 0.9912.  An accumulation time of 5 minutes, a potential of -1.75 V and a concentration of 35 % KOH were the conditions that presented better results. These results give way to evaluating battery membranes separators like Celgard and cellophane in order to see which membrane exhibits the best prevention of Cu crossover.