Fluorescent-tagged hyper-branched polyester for inhibition of CaSO4 scale and the scale inhibition mechanism

A fluorescent-tagged and carboxyl-terminated hyper-branched waterborne polyester (HBP-AP) was prepared and characterized. Acted as CaSO 4 scale inhibitor, its application conditions such as the dosage, Ca 2+ concentration and pH value, were investigated to optimize the scale inhibition efficiency. In order to provide some theoretical supports for the scale inhibition mechanism of hyper-branched polymers, the scale inhibition mechanism for CaSO 4 was then investigated in detailed. The experimental results showed that the HBP-AP provided an excellent scale inhibiting efficiency for CaSO 4 , which was as high as 98.8 % at dosage of 15 mg/L, and performed well both at high Ca 2+ concentration and extended pH value. Besides, the HBP-APTA showed good solubilizing property and dispersion ability. The XRD , SEM and CLSM have been used to character the CaSO 4 scale crystal. Especially, with the help of CLSM technology, it is convenient to observe how the prepared hyper-branched inhibitor affected both the CaSO 4 crystal nucleation process and crystal growing process, allowing us to understand the scale inhibition mechanism easily for its leading the scale inhibition process visualization.