Summary: Preparation of Biosilica-enriched Filler and an Example of its Use in a
Nano-Particle Retention System
Jan Pekarovic, Alexandra Pekarovicova and Paul D. Fleming III.
Department of Paper Engineering, Chemical Engineering, and Imaging, Western Michigan University, A-231
Parkview, Kalamazoo MI 49008
Silica deposited within the plant tissue in small bodies phytoliths is leached by an alkaline solution. Up to 70-
75% of biosilica from wheat/rice straw becomes solubilized. The reaction kinetics is shown. Solubilized
biosilica is recovered and reused in the papermaking process, via the causticizing reaction. The chemical
composition, surface charge, charge demand and size distribution of newly designed filler is shown. The
positive effect of this filler in nano-particle retention system is demonstrated.
Most of the non-wood fibers for papermaking are derived from annual plants. The advantage of annual plants
is that they can be grown on farmland and harvested each year with high yields (5-20 ton/ha depending on the
crop type). As renewable resources, they can be replaced annually, compared with the much longer growth
cycle for wood.
Non-wood pulp production, which represents less than 10% of the total world's pulp source, is based primarily
on straw (46%), bagasse (14%), and bamboo (6%). Agricultural by-products account for 73% of the world's
non-wood capacity, while natural plants such as reed and bamboo account for 18%, and the remainder consists
mainly of industrial crops (1).