CTS-9215421 University of Utah Jan D. Miller ABSTRACT The objective of this project is to understand the surface chemistry of deinking flotation process for wastepaper recycling as a basis for improving the performance of air-sparged hydrocyclone (ASH) units in this application. Major problems in deinking floatation such as separation of ink from the fiber surface during pulping, differences in hydrophobicity of ink due to oxidation, heterocoagulation of ink particles with fibers, and entrapment of ink particles by entanglement of cellulose fibers will be addressed. Increased yields and greater brightness of recycled paper are expected with optimal operating conditions for ASH flotation. There are significant incentives to increase domestic paper recycling efforts. As much as 50% of the landfill requirement in the United States derives from paper and paper products. Aside from the waste disposal problem, paper recycling will conserve trees, water and energy.