Why is there no more focus on biobased source materials for activated carbon?

The search for more sustainable forms of activated carbon in recent decades has resulted in a strong increase in scientific research into biobased alternatives. In this respect the focus is on source materials that are not only suitable for conversion into activated carbon but are also sufficiently available, such as waste streams from the fruit industry, wood residues and even seaweeds.

Although these alternatives seem attractive from an ecological point of view, it is important to remain critical when assessing their actual sustainability and effectiveness.

It is often claimed that biobased activated carbon has a lower CO₂ footprint than conventional carbon based on fossil sources. In theory, this is correct: biogenic materials absorb CO₂ from the atmosphere during their growth, which has a positive effect on carbon balance. In practice, however, this story turns out to be more complex and, above all, more nuanced:

• Production processes such as carbonisation and activation require high temperatures, often achieved using fossil fuels.
• The logistics of seasonal or geographically dispersed biomass can negate the CO₂ gain.
• Land use and associated indirect effects such as deforestation or monoculture, through which the biobased source materials become available, can lead to ecological damage, even in ‘sustainable’ biomass streams.

An objective and correctly conducted life cycle analysis (LCA) is essential to assess the true environmental impact of biobased activated carbon. Without this, there is a risk that ‘green’ alternatives are primarily marketing-driven.
 
A second point of attention is the availability of biobased raw materials. Many biomass streams are seasonal (such as fruit stones) or subject to external factors such as logging. This makes it difficult to guarantee a stable supply, which is crucial for industrial applications where continuity is key.
 
Last but not least: there is obviously also the technical aspect. Biobased activated carbon must not only be sustainable, but also have a high adsorption capacity. In other words, the carbon must be capable of removing the necessary contaminants from water, air, etc. Some biobased carbons have a less developed pore structure and/or a lower adsorption capacity, meaning more product is needed to achieve the same purification result, with a potentially higher ecological and economic cost.

Sustainability is more than a label. Cargen researches and evaluates biobased alternatives based on CO₂ impact, availability, ecological integrity and practical performance. Only this way customers can be offered a guaranteed solution that is both technically and ecologically responsible.

Alternative biobased source materials for the production of activated carbon seem attractive from both an ecological and commercial point of view. However, a thorough evaluation based on a life cycle analysis, the stable or unstable availability of the source material, and the technical performance of the biobased activated carbon type is required.