Biorefineries aim to convert low value biomasses into high value products. The feedstock biomasses are often high-silica agricultural waste products such as rice straw, wheat straw, corn stover, sugarcane bagasse, or empty fruit bunches. This causes challenges, since silica is problematic in industrial processes, where it forms water-insoluble precipitates that are hard to remove, block filtration systems, and cause instrumental defects. In this paper we review various industries that experience issues with silica. These include paper pulping and waste-water treatment, where they try to solve their problems with silica in different ways. High pH and co-precipitation with mineral elements are some common ways of alleviating silica problems. Reviewing the literature for the fundamentals of silica revealed a complex chemistry that is not yet fully understood. Much is still to be learned about the interactions between silica and organic material as well as the mechanisms of silica precipitation and dissolution. Understanding the fundamental and complex chemistry of silica might help developing better solutions than those existing today, allowing efficient use of high silica biomasses in biorefineries.
- Silica chemistry
- Silica precipitation
- Silica depolymerization
- Silica solubility
Le, D. M., Sørensen, H. R., Knudsen, N. O., & Meyer, A. S. (2015). Implications of silica on biorefineries – interactions with organic material and mineral elements in grasses. Biofuels, Bioproducts and Biorefining, 9, 109-121. https://doi.org/10.1002/bbb.1511