Carboxylate-Terminated Double-Hydrophilic Block Copolymer Containing Fluorescent Groups: An Effective and Environmentally Friendly Inhibitor for Calcium Carbonate Scales

Allyloxy polyethoxy ether (APEG) and succinic anhydride were used to prepare allyloxy polyethoxy carboxylate (APEL). 8-hydroxy-1,3,6-pyrene trisulfonic acid trisodium salt (PY) was reacted with allyl chloride to produce fluorescent monomer 8-allyloxy-1,3,6-pyrene trisulfonic acid trisodium salt (PA). APEL and PA were copolymerized with acrylic acid (AA) to synthesize PA tagged no phosphate and nitrogen free CaCO3 inhibitor AA-APEL-PA. Structures of PA, APEG, APEL, and AA-APEL-PA were carried out by FT-IR and 1H-NMR. The observation shows that the dosage of AA-APEL-PA plays an important role on CaCO3 inhibition. The effect on formation of CaCO3 was investigated with combination of scanning electronic microscopy and X-ray powder diffraction analysis. Relationship between AA-APEL-PA's fluorescent intensity and its dosage was studied. Correlation coefficient r of AA-APEL-PA's fluorescent intensity and its dosage is 0.9998. AA-APEL-PA can be used to accurately measure polymer consumption on line besides providing excellent CaCO3 inhibition.