Performance Analysis of GLDA and HEDTA as Chelators for Calcium and Ferrum Ions at 80 °C: A Combined Molecular Modeling and Experimental Study

Chelators are chemical compounds that bind to metal ions, forming stable complexes and preventing these ions from participating in undesirable chemical reactions. Their ability to control metal ion availability and prevent scale formation makes them valuable across numerous industries, including industrial cleaning, medicine, agriculture, water treatment, oil and gas, cosmetics, and the food industry. In the oil and gas sector, particularly effective chelators are essential as additives in production chemicals, especially those that remain stable under highly acidic conditions (pH 1-3). However, the availability of chelators that can effectively function under such harsh conditions is limited. This study aims to evaluate the performance of tetrasodium glutamate diacetate (GLDA) and hydroxyethylenediamine triacetic acid (HEDTA) as chelators for calcium (Ca²⁺) and iron (Fe²⁺) ions in these extreme conditions across various temperatures. The performance of these chelators was assessed through computational methods, including Density Functional Theory (DFT) and Monte Carlo simulations. DFT quantum chemistry calculations indicated that GLDA potentially offers superior electron transfer capabilities, resulting in stronger adsorption properties compared to HEDTA. Additionally, Monte Carlo calculations revealed that GLDA exhibits slightly higher adsorption energy than HEDTA. Experimental results further supported these findings. For calcium ions (Ca²⁺) at pH 3, GLDA proved to be a more effective chelator than HEDTA, while HEDTA performed better at pH 1. Regarding iron ions (Fe²⁺), GLDA outperformed HEDTA at both pH levels, demonstrating its superior chelating ability. These insights suggest that GLDA may be a more robust and versatile chelator for use in the highly acidic environments typical of oil and gas production, providing a potential solution to the current limitations in effective chelation under such conditions.