Carboxyl or phosphate functionalization polyamidoamine dendrimer efficient scale inhibitor: Preparation and properties

Abstract

Stringent water resources scarcity and severe environmental restriction requires environmentally friendly and efficient scale inhibitors exploitation. Functionalization of polyamidoamine dendrimers for scale inhibitor was performed using 2-phosphate-1, 2, 4-butane tricarboxylic acid (PBTCA) and succinic anhydride (SA). In this study, PBTCA modified polyamidoamine dendrimers (PAMAM-1), SA modified first and second generation polyamidoamine dendrimers (CAMAM-1 and CAMAM-2) are prepared. Static scale inhibition method is employed to assess the scale inhibition efficiency of linear low molecular polyacrylic (LPAA), PBTCA, PAMAM-1, CAMAM-1 and CAMAM-2 against CaCO3 and CaSO4. The results show that carboxyl terminated polyamidoamine dendrimers has excellent scale inhibition performance comparable to PBTCA and PAMAM-1. Compared to LPAA and PBTCA, dendritic structure can effectively improve the scale inhibition performance of the scale inhibitor. Furthermore, the scale inhibition performance enhances with increasing generation of carboxyl-terminated polyamidoamine dendrimer. The inhibition efficiency of CAMAM-2 against CaCO3 and CaSO4 is about 96.3% and 95.2% at a concentration of 10 mg/ L. Moreover, The CAMAM-2 performs above 85% scale inhibition at Ca2+concentration is 4000 mg/L and 90% scale inhibition at border pH 5–9. The FT-IR, XRD and SEM-EDX results show that the CaCO3 changes from stable calcite to metastable aragonite and vaterite, and the needle like structure of CaSO4 is destroyed to small crystals. CAMAM-2 only occupies the crystallization site and distorts the lattice of calcium scale in the crystal growth process rather than adsorb on the final crystal surface. This paper provides data support for the application of phosphate or carboxyl terminated polyamidoamine dendrimer in scale inhibition.