Eco-friendly biomass pretreatment method yields efficient biofuels and adsorbents

As global demand for sustainable energy solutions increases, bioethanol production from lignocellulosic biomass is gaining traction. However, traditional methods face limitations due to high processing costs and waste issues. A recent study led by Xinchuan Yuan, published in the Journal of Bioresources and Bioproducts, presents an innovative biomass pretreatment method that not only improves bioethanol production efficiency but also utilizes biomass residues as bio-adsorbents for wastewater treatment, potentially transforming the industry.

Producing bioethanol from lignocellulosic biomass is essential for developing sustainable fuels. However, existing pretreatment methods often involve high sugar loss and require intensive solid-liquid separation, adding to production costs. This study introduces a densification pretreatment approach that uses sulfuric acid and metal salts under mild autoclave conditions, which reduces energy requirements and operational costs.

The researchers employed a combination of sulfuric acid and metal salts, specifically FeCl₃ and ZnCl₂, for pretreatment at 121°C. This process, called densified lignocellulosic biomass with sulfuric acid and metal salts (DLCA(SA-MS)), allows biomass loading as high as 400 kg/m³, a substantial increase over typical levels. The DLCA(SA-MS) biomass achieved over 95% sugar retention and 90% enzymatic sugar conversion, reaching a high fermentable sugar concentration of 212.3 g/L. This advancement could increase bioethanol yields, meeting growing energy needs sustainably.

Beyond bioethanol, the study also addresses the environmental impact of lignocellulosic residue. After bioethanol extraction, DLCA(SA-MS) residues were processed into bio-adsorbents. These bio-adsorbents exhibited strong adsorption properties for dyes like methyl orange and methylene blue, which are common pollutants in textile wastewater. The bio-adsorbents achieved removal rates of over 90% for methyl orange and 80% for methylene blue, offering an effective and eco-friendly solution for industrial wastewater treatment.

The DLCA(SA-MS) pretreatment method demonstrates significant potential in industrial applications by increasing bioethanol production efficiency and providing a sustainable approach to managing biomass residues. With its dual benefits—enhanced biofuel yields and dye wastewater treatment—this method aligns well with current environmental goals and economic pressures for sustainable biorefinery operations.

This new approach marks an important step toward full-component utilization of lignocellulosic biomass, reducing production costs, and improving environmental outcomes. Future research will focus on scaling up the process and further refining pretreatment conditions to maximize benefits.

DOI:

https://doi.org/10.1016/j.jobab.2024.09.004

Funding:

This research received support from the School of Environmental and Biological Engineering, Nanjing University of Science and Technology, and other institutional sponsors.

Citation:

Yuan, X., Shen, G., Huo, J., Chen, S., Shen, W., Zhang, C., & Jin, M. (2024). Enhanced biomass densification pretreatment using binary chemicals for efficient lignocellulosic valorization. Journal of Bioresources and Bioproducts, 9, 548–564. https://doi.org/10.1016/j.jobab.2024.09.004