Preparation and properties of fluorescent polyaspartic acid derivatives with enhanced scale and corrosion inhibition

Owing to the limitations of conventional polyaspartic acid (PASP) in scale inhibition, corrosion inhibition, and real-time monitoring, a novel fluorescent tracer-type inhibitor (Tyr-Gly-PASP) was synthesized by grafting tyrosine (Tyr) and glycine (Gly). Its structure was characterized by infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), fluorescence analysis (FA) and X-ray photoelectron spectroscopy (XPS). Tyr-Gly-PASP exhibited superior scale inhibition efficiency of over 90% for CaCO₃ and CaSO₄, As observed by scanning electron microscopy (SEM), it transformed CaCO₃ from calcite to vaterite and dispersed CaSO₄ crystals. For Q235 steel, its corrosion inhibition efficiency reached 90.01%, which was 34.31% higher than PASP, and the adsorption behavior followed the Langmuir isotherm. Its fluorescence intensity increased linearly with concentration, enabling real-time dosage monitoring. Tyr-Gly-PASP combines scale inhibition, corrosion inhibition, and fluorescent tracing, which fills the gap of single-function PASP and providing a multifunctional water-treatment agent for industrial circulating water systems.