Fluorescent-tagged block copolymer as an effective and green inhibitor for calcium sulfate 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 maleic anhydride (MA) to synthesize PA tagged no phosphate and nitrogen free CaSO₄ inhibitor MA–APEL–PA. Structures of PA, APEG, APEL, and MA–APEL–PA were identified by ¹H NMR. The observation shows that the dosage of MA–APEL–PA plays an important role on CaSO₄ inhibition. The effect on formation of CaSO₄ was investigated with scanning electron microscope (SEM) analysis. Relationship between MA–APEL–PA’s fluorescent intensity and its dosage was studied. Correlation coefficient R ² of MA–APEL–PA fluorescent intensity and MA–APEL–PA dosage is 0.9991.