# Synthesis of DHTA-Modified Poly(Epoxysuccinic Acid) and Scale Inhibition of Fluoride Scale

## TL;DR

A new modified polymer was created to prevent calcium fluoride scale buildup on reverse osmosis membranes, showing excellent performance in lab tests.

## Contribution

The synthesis of DHTA-PESA and its effectiveness in inhibiting CaF2 scale through multiple mechanisms is novel.

## Key findings

- DHTA-PESA achieved nearly 100% CaF2 scale inhibition at 200 mg/L in static tests.
- Dynamic experiments showed DHTA-PESA effectively disperses CaF2 and reduces membrane fouling.
- Crystal analysis revealed DHTA-PESA alters CaF2 crystal morphology through dispersion, lattice distortion, and chelation.

## Abstract

To alleviate CaF2 scaling on reverse osmosis membranes, polyepoxysuccinic acid (PESA) was modified with 2,5-dihydroxyterephthalic acid (DHTA) to obtain DHTA-PESA. Its structure and thermal stability were confirmed through characterization. Scale inhibition performance was evaluated using static and dynamic experiments. Results showed that in static tests, at a dosage of 200 mg/L, DHTA-PESA achieved a CaF2 scale inhibition rate of nearly 100%, demonstrating Ca2+ chelation ability and the capacity to prolong crystallization induction time. In dynamic experiments, indicating superior CaF2 dispersion performance and effective mitigation of membrane fouling. X-ray diffraction and scanning electron microscopy analysis revealed that DHTA-PESA induces irregular growth of CaF2 crystals, disrupting their formation and altering crystal morphology. The primary scale inhibition mechanisms include dispersion, lattice distortion, and chelation.