Preparation of fluorescent polyaspartic acid and evaluation of its scale inhibition for CaCO3 and CaSO4

Polysuccinimide was synthesized from maleic anhydride and urea. A polyaspartic acid derivative (PASP‐Try‐SEA) was synthesized from the polysuccinimide with 2 ‐aminoethanesulfonic acid and tryptophan. The products were characterized by UV, FTIR,¹H NMR, TGA and PL, respectively. The results showed that the fluorescent chromophore‐indolyl groups were successfully incorporated into PASP. The relationship between the fluorescence intensity and the concentration of fluorescent polyaspartic acid (FPASP) is linear with the excitation wavelength of 366 nm and 422 nm. FPASP also showed excellent scale inhibition properties with a scale inhibition rate of 78% achieved for CaCO₃ with a dosage of 9 mg/L and a significantly enhanced scale inhibition effect for CaSO₄, achieving an inhibition rate of 98%, which were determined using the static scale inhibition method. When FPASP was added to the solution, CaCO₃ and CaSO₄ deposits showed flower patterns with floppy accumulation by scanning electron microscopy. Copyright © 2016 John Wiley & Sons, Ltd.