Synthesis of fluorescent-tagged scale inhibitor and evaluation of its calcium carbonate precipitation performance Original Research Article

A novel fluorescent-tagged scale inhibitor, maleic anhydride–oxalic acid–allypolyethoxy carboxylate–8-hydroxy-1,3,6-pyrene trisulfonic acid trisodium salt (pyranine) (MA–APEM–APTA) was synthesized by maleic anhydride (MA), oxalic acid–allypolyethoxy carboxylate (APEM) and 8-hydroxy-1,3,6-pyrene trisulfonic acid trisodium salt (APTA). Structures of APTA, APEM, and MA–APEM–APTA were carried out by FT-IR and 1H NMR. The observation shows that the dosage of MA–APEM–APTA plays an important role on CaCO3 inhibition. It can be concluded that the order of preventing the precipitation from flask tests was MA–APEM > MA–APEM–APTA > T-225 > PESA > PAA ≈ HPMA. Relationship between MA–APEM–APTAʹs fluorescent intensity and its dosage was studied. Correlation coefficient R2 of MA–APEM–APTAʹs is 0.9973. The effect on formation of CaCO3 was investigated with combination of scanning electronic microscopy (SEM), transmission electron microscope (TEM), X-ray powder diffraction (XRD) and FT-IR analysis. MA–APEM–APTA can be used to accurately measure copolymer consumption on line besides providing excellent CaCO3.