A low-phosphorus PASP-based inhibitor for corrosion and scale control in industrial circulating water: performance evaluation and mechanistic insights

The development of efficient low-phosphorus water treatment formulations is essential for sustainable industrial water management. In this study, a novel quadri-component corrosion and scale inhibitor PPHZ was developed by rationally combining biodegradable polyaspartic acid (PASP), phosphonobutane-tricarboxylic acid (PBTCA), hydrolyzed polymaleic anhydride (HPMA), and ZnCl2. The formulation exhibits excellent dual-functional performance in both scale and corrosion inhibition. At a dosage of 50 mg/L, PPHZ achieves 95% CaCO3 scale inhibition by effectively distorting crystal growth and completely transforming calcite/aragonite into non-adherent vaterite. Notably, only 10 mg/L of PPHZ is sufficient to completely inhibit CaSO4 scale formation. In simulated circulating water, PPHZ achieves a corrosion inhibition efficiency of 90% for carbon steel at 30 mg/L. Electrochemical analysis reveals that PPHZ simultaneously suppresses both anodic and cathodic reactions through a ‘Zn2+-bridging’ hybrid film mechanism, while surface characterization (SEM–EDS, XRD) confirms the formation of a dense hybrid protective film. The formulation has a theoretical phosphorus content of only 2.296%, achieving >92% phosphorus reduction compared to conventional phosphorus-based agents, in line with the sustainable development trend of water treatment technologies. PPHZ provides an effective strategy for integrated corrosion and scale control in industrial water systems.