A novel strategy for turning problematic silica-rich raw material into silica-free sustainable green feedstock for biorefinery

The heavy reliance on wood for pulp and paper production has led to a shortage of fibrous resources and accelerated deforestation. In response, non-wood alternatives have gained increasing attention; however, materials such as wheat straw pose challenges due to their high silica content. To address this issue, a combined mechanical, physical, and chemical process was developed to reduce the silica content of wheat straw. In this study, wheat straw was shredded and sieved to obtain particle sizes ranging from <45.0 mm to >3.0 mm (sieve size). The particles were treated with hot water, allowed to settle to facilitate silica precipitation, then washed and centrifuged. Subsequently, they were prehydrolyzed under alkaline conditions, followed by additional washing and centrifugation. Both the raw wheat straw and the prehydrolyzed wheat straw (PHWS) were analyzed for silica content, fiber morphology, and carbohydrate composition. The process reduced the silica content by more than 99% and preserved the fiber properties, chemical composition, and carbohydrate composition of the raw material. Notably, the study identified the specific locations of silica within the wheat straw and evaluated the removal efficiency for each location. This approach offers a sustainable pathway for producing renewable biomaterial feedstocks, creating new opportunities for biorefineries and promoting sustainable resource utilization.