Every year, the forestry and timber industries produce vast quantities of tree bark as a byproduct. Most of this material is burned, discarded, or left to decompose. At the same time, there is an urgent need to develop scalable and affordable technologies to capture carbon dioxide.
“Our research brings these two issues together through a simple but impactful idea, transforming waste into a resource,” says Suresh Bhargava, director of the Centre for Advanced Materials and Industrial Chemistry at RMIT University.
Bhargava and his colleagues have converted the bark of the eucalyptus tree into a porous carbon material that can help clean water, filter air and capture carbon dioxide. They reported their simple two-step method in a paper published in the journal Biomass and Bioenergy.
Porous carbon materials, which contain a sophisticated network of pores, are already used in filtration and gas treatment systems. Their pores capture contaminants or targeted molecules as water or air pass through. But, says Bhargava, “conventional methods for producing porous carbon materials are often energy-intensive, requiring high temperatures and multiple processing steps, which limits scalability.”
The RMIT team developed a simple and scalable synthesis approach to make their carbon filter from eucalyptus bark. They first make a carbon-rich material called a hydrochar by heating wet bark at low temperature under pressure. Then they physically mixed the hydrochar with zinc chloride.
This results in a highly porous carbon material with a surface area of approximately 2,210 square meters per gram of the material. The porous material captures around 7 millimoles per gram of CO₂, placing it among competitive carbon capture materials, Bhargava says.
“The choice of eucalyptus bark is both practical and scientifically grounded,” he adds. Eucalyptus bark is a widely available, low-cost resource. Australia is home to more than 900 species of eucalyptus and related trees, and eucalyptus is also cultivated widely around the world.
The bark contains lignin and cellulose that lead to the formation of stable carbon frameworks with well-developed porosity. Compared to other biomass sources, it produces materials with higher surface area and better CO₂ adsorption performance.
The abundance of the raw materials and the simplicity of the synthesis process makes this approach inherently scalable. The researchers are now trying to evaluate long-term durability, regeneration, and performance under real operating conditions. And they are seeking industry collaborations to explore commercialization opportunities.
“While further work is needed to evaluate long-term durability and large-scale deployment,” says Bhargava, “this study provides a clear pathway toward more sustainable and economically viable carbon capture technologies.”
Source: Pallavi Saini et al. Sustainable valorisation of eucalyptus bark waste into microporous carbon materials for efficient CO2 capture. Biomass and Bioenergy, 2026.
