This study is focused on the evaluation of polyepoxysuccinic acid (PESA),
2-phosphonobutane 1,2,4-tricarboxyllic acid (PBTC), and PESA/PBTC blends for calcium sulfate dihydrate (gypsum) and calcium carbonate scale inhibition for aqueous systems. For comparison, synthetic, bio-, and hybrid polymers were also tested for their efficacy as scale inhibitors. It has been observed that performance of inhibitors depends on inhibitor dosage and functional groups. Results also reveal that PBTC exhibits synergistic effect on the performance of polymers containing carboxyl group. Scanning electron microscopic studies of the gypsum crystals grown in the presence of anionic inhibitors show that structures of these crystals are highly modified. XRD data collected for calcium carbonate in the presence and absence of inhibitors confirm the presence of calcite as the major phase.
Keywords: scale, inhibition, PESA, PBTC, PESA/PBTC blends, crystals morphology