dispersante

A dispersante is a substance intended to improve the distribution of solid particles, droplets, or pigments within a medium. It works by adsorbing to particle surfaces to prevent agglomeration and by modifying interfacial properties, often reducing the energy barrier to break up larger entities into smaller ones.

Applications span multiple industries. In paints and coatings, inks, and pigment formulations, dispersants help maintain stable suspensions and uniform color. They are also used in agrochemical formulations, ceramic slurries, and cosmetic emulsions. In environmental response, chemical dispersants are employed to disperse oil slicks into the water column to enhance natural biodegradation under appropriate conditions.

Types and mechanisms. Dispersants can be broadly categorized as surfactant-based, polymeric, or inorganic. Surfactant dispersants reduce interfacial tension between phases and provide electrostatic stabilization. Polymeric dispersants use grafted or comb-like polymers to create steric barriers that keep particles apart. Inorganic dispersants include solid particles that induce mechanical separation or modify flow and suspension properties. Stabilization mechanisms include electrostatic stabilization (via zeta potential), steric stabilization (polymer layers), and a combination known as electrosteric stabilization.

Oil spill context. Chemical dispersants are designed to increase the dispersion of surface oil into subsurface layers, facilitating dilution and biodegradation. Their effectiveness depends on oil type, water temperature, salinity, and sea state, and their use requires environmental risk assessment and regulatory approval.

Environmental and regulatory considerations. Dispersants can pose toxicity risks to aquatic life and may alter soil and water quality. Regulatory frameworks typically require safety testing, application guidelines, and performance evaluations, with preference given to formulations that balance efficacy and environmental impact.