Visualization of toner ink adsorption at bubble surfaces

摘要

Toner ink interactions with bubble surfaces were investigated in laboratory-scale flotation deinking processes using high magnification and high temporal resolution digital video. The role of calcium in sodium oleate and sodium lauryl sulfate surfactant systems was examined. Stable adsorption of large toner particles and of toner particle complexes were observed at surfaces of stationary and suspended bubbles for several system chemistries. Image analysis techniques were used for direct measurements of the effect of particle size and system chemistry on bubble surface coverage and mass of adsorbed ink per bubble. Surfactants in the presence of calcium were seen to promote toner particle agglomeration at the surfaces of stationary bubbles. The presence of calcium also appears to increase mass of adsorbed toner at bubble surfaces for both sodium oleate and sodium lauryl sulfate chemistries; for 250 to 450 μm sized particles in oleate chemistry, the mass of ink attached per bubble increased from 6 mg to 12 mg. The mass of attached toner particles was also seen to increase with particle size.