Title : Evaluation of a novel corrosion inhibitor for lead sequestration in aqueous systems
Abstract:
This work presents a detailed investigation into the solution stability and lead-binding performance of a polymer-based corrosion inhibitor, through a collaborative project between Roemex Ltd and the University of Leeds. Thermogravimetric analysis (TGA) indicated that the inhibitor contained primary components of sodium polyaspartate polymer, and ADBAC surfactant. Stability testing confirmed the inhibitor remains stable at high concentrations (up to 500 ppm) and under acidic conditions (pH < 7), making it suitable for diverse application environments.
Turbidity and visual inspection tests demonstrated the polymer's ability to interact with lead ions (Pb 2+), with clear precipitation observed at elevated concentrations (200 ppm of PbCl₂ or Pb(NO₃)₂). Dynamic Light Scattering (DLS) measurements revealed the polymer forms large globules in solution, which shrink in the presence of 1% NaCl, confirming that ionic strength influences polymer conformation and solubility. Atomic Absorption Spectroscopy (AAS) using both membrane filtration and direct extraction methods showed that the polymer sequesters over 90–95% of Pb2+ ions at higher concentrations. Additionally, the inhibitor showed clear selectivity for lead ions over Ca2+, as an analogue for other divalent metals present in the environment, where polymer stability was maintained even in elevated levels of calcium. These findings confirm the inhibitor's potential to capture lead efficiently and highlight its possible applications in industrial corrosion control and environmental remediation.
Outside of the polymers interaction with dissolved lead, investigations were conducted into whether it acts to accelerate leaching from lead scale surfaces (PbCO₃ and PbS). Additional work also included electrochemical corrosion testing with polymer-coated lead surfaces, to understand how corrosion inhibition is influenced by background free lead ions in the solution.
