Calcium carbonate scale deposition is a major problem in industrial cooling systems. In most cases it reduces the overall flow rate, limits thermal exchanges and in some cases may even lead to a complete shutdown of the installations. Various chemical additives have been proposed to inhibit scale deposits. Due to more and more severe ecological constraints, the use of biodegradable inhibitors has some promising prospects. Polyaspartate as a green scale inhibitor
can be prepared by different synthetic routes. Preparation conditions influence both scale inhibition efficiency and biodegradability. Scale inhibition is evaluated by the EQCM method under different dynamic conditions in waters of different characteristics. Biodegradability is
analysed by the respiration of biomass in the presence of polyaspartates. Links for preparation of efficient green inhibitors were thus obtained. The more biodegradable and the best scale inhibiting polyaspartates are synthesised by bulk polycondensation in mixed solvents with catalyst. All scaling tests performed in the presence of polyaspartates develop the vaterite morphology form of calcium carbonate.
Keywords • Polyaspartates, carbonate scale inhibition, EQCM, synthesis, biodegradability, crystal morphology, vaterite.