A model description of the adsorption of surfactant-rich stickies onto hydrophobic and hydrophilic mineral surfaces

“Stickies” are tacky species, present in recycled paper and coated broke, derived from coating formulations, adhesives etc. They impact negatively on paper quality and cause web runnability problems by deposit build-up. To sustain recycling, stickies are controlled by adsorbing them onto minerals added to the recycled stock. We report isotherms for a fatty acid ester defoamer and an acrylic acid ester copolymer adsorbing from colloidal suspension onto talcs and modified calcium carbonates. We used commercial preparations of the fatty acid ester defoamer and acrylic acid ester copolymer as model systems for the study of more complex systems. The modified calcium carbonates are hydrophilic with anionic and cationic sites present. Adsorption isotherms for the low surface area modified calcium carbonate conform to the Langmuir model, while those for the high surface area modified calcium carbonate reflected a two stage process involving the formation of a monolayer over the mineral surface and subsequent partial