Experimental and theoretical studies of fluorescent-tagged scale inhibitors for calcium scale inhibition

A novel fluorescent-tagged scale inhibitor (HPTS-AA-CS-X) containing fluorescent monomer, acrylic acid, and chitosan were designed and prepared. The structures and thermal stability of HPTS-AA-CS-X were characterized by FTIR, TGA and 1 H NMR. HPTS-AA-CS-2% had excellent fluorescence performance (R 2 was 0.9916). Different experimental factors (temperature, pH value, using time, and Ca 2 + concentration) were studied. HPTS-AA-CS-2% is an efficient scale inhibitor in calcium carbonate (10 mg/L, 93.8%) and calcium sulfate (5 mg/L, 94.2%). The scale inhibition mechanism was studied by SEM, XRD, XPS, and DFT. For calcium carbonate, HPTS-AA-CS-2% prevent growth of crystal surface, the crystallinity decreased, and crystal shape changed from calcite to aragonite with poor stability. HPTS-AA-CS-2% does not change crystal type of calcium sulfate, but it will reduce crystal strength of calcium sulfate. This work shows the potential and possibility of HPTS-AA-CS-2% for calcium scale inhibition and provides experimental and theoretical basis for developing a new fluorescent-tagged water treatment agent. (c) 2022 Elsevier B.V. All rights reserved.