A novel dual-function antiscalant carboxymethyl cellulose-graft-protocatechuic acid for efficient scaling and biofouling prevention

Despite antiscalants playing a critical role in desalination and cooling water systems, their potential to support microbial growth pose a significant threat to water treatment processes by promoting biofouling. In this work, a novel dual-function antiscalant carboxymethyl cellulose-graft-protocatechuic acid (CMC-g-PA) was prepared using plant-derived antibacterial protocatechuic acid (PA) and natural polysaccharide cellulose, and its scale inhibition effect on CaSO₄ scale and antibacterial performance on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were evaluated. Results indicated that the inhibition efficiency against CaSO₄ scale and the induction time of CaSO₄ crystallization process in the presence of CMC-g-PA were remarkably enhanced compared to unmodified CMC. Microscope and XRD characterizations demonstrated significant alterations in the crystal morphology and size of the formed scale using CMC-g-PA as antiscalant. Molecular dynamics (MD) analysis also showed that CMC-g-PA could intensively interact with the crystal plane of CaSO₄ with the binding energy reaching 746.73 kcal/mol, thereby affecting crystal growth and causing crystal distortion. Additionally, an obvious inhibitory effect of CMC-g-PA on the growth of E. coli and S. aureus was observed, attributed primarily to the antibacterial activity of the introduced phenolic hydroxyl groups. In short, bio-derived CMC-g-PA, characterized in its environmental-friendliness, antiscaling efficiency and antibacterial activity, holds immense potential for mitigating scaling and biofouling in desalination/cooling water systems.