Polyaspartate Scale Inhibitors-Biodegradable Alternatives to Polyacrylates

Polyaspartates are highly biodegradable alternatives to polyacrylate based scale inhibitors. This paper presents laboratory testing data on polyaspartate inhibitors of calcium and barium mineral scales. The optimum molecular weight for polyaspartate inhibitors of calcium carbonate, calcium sulfate and barium sulfate mineral scales was determined to be between 1,000 and 4,000 Mw (weight average molecular weight as calculated by Size Exclusion Chromatography). For inhibition of calcium carbonate and barium sulfate, polyaspartates in the range of 3,000-4,000 Mw were most effective. For calcium sulfate inhibition, the optimum molecular weight lies in the 1,000 to 2,000 Mw range. Biodegradability data (OECD 301B Ready Biodegradability) on polyaspartates of a variety of molecular weights is also presented which demonstrates the high biodegradability of this class of mineral scale inhibitors.