Innovative application of green surfactants as eco-friendly scale inhibitors in industrial water systems

Abstract

Scale deposition poses significant challenges in various industrial utilities, necessitating the development of eco-friendly scale inhibitors in line with environmental regulations. This study investigates the potential of two natural surfactants, Casein and Rhamnolipid, as innovative inhibitors for calcium carbonate (CaCO3) scale formation, offering an alternative to traditional water treatment chemicals. The anti-scaling characteristics of these two green surfactants were performed using conductivity and electrochemical impedance spectroscopy (EIS) techniques. Additionally, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to analyze the morphology of CaCO3 crystals and understand the structural changes induced by surfactant interaction. The results revealed that Rhamnolipids significantly outperform Casein in suppressing scale formation, attributed to the adsorption of their multiple functional groups onto scale microcrystals. This adsorption modifies the crystal structure and inhibits further growth. Computational studies were employed to investigate the inhibition mechanism of these surfactants. The spatial and electrical configurations of optimal molecular structures are also analyzed using the Density Functional Theory (DFT) approach. Monte Carlo simulations on the CaCO3 (104) surface demonstrated that Rhamnolipids exhibit superior inhibition compared to Casein, as evidenced by their higher adsorption energy, indicating a more stable binding to the surface. Overall, this research highlights the potential of these natural surfactants as sustainable scale inhibitors, particularly in industries such as food and pharmaceuticals, thereby contributing to environmentally friendly water treatment solutions.