Specific Ion Effects in the Handling of Particle Suspensions: A Review

Abstract

Specific ion effects (SIEs) play a pivotal role in governing particle suspension behavior and manipulation across diverse scientific and industrial fields. This review summarizes the underlying mechanisms of SIEs, focusing on ion accumulation at particle interfaces, Hofmeister series implications, electrokinetic properties, and their impact on coagulation, dispersion, and rheological characteristics. It examines the interplay among ion identity, concentration, and surface properties—including hydrophilicity, hydrophobicity, and surface-charge density—offering critical insights into particle–particle interactions. Particular emphasis is placed on the structural and electrostatic roles of the electrical double layer and the Stern layer. Recent advances in understanding the microscopic origins of SIEs, facilitated by innovative experimental approaches and computational modeling, are also highlighted. This review explores the influence of SIEs on aggregate formation and stability, gelation behavior, and suspension viscoelastic properties. These insights underscore the significance of accounting for SIEs across disciplines such as chemistry, industry, agriculture, environmental science, biology, and medical science, and emphasize the need for continued advances to realize innovative applications and transformative solutions.