Global food waste is projected to reach 3.4 billion tons by 2050, presenting a massive economic and environmental challenge that currently costs billions of dollars annually. Apple pomace is a particularly problematic byproduct because its high water content makes it prone to rapid fermentation, which can lead to the growth of disease-carrying vectors and the contamination of groundwater. When this organic matter is left to decompose in landfills, it releases methane, a greenhouse gas with a high potential to accelerate climate change. Traditionally underutilized, this residue is rich in phenolic compounds, dietary fibers, and polysaccharides that can be captured and repurposed through thermochemical conversion. This approach allows industries to divert millions of tons of waste from landfills while simultaneously creating a stable carbon material that locks away greenhouse gases for centuries.

The research finds that the temperature used during the production process is the most critical factor in determining how the biochar will perform. When apple pomace is heated to low or intermediate temperatures between 300 and 600 degrees Celsius, it retains a high density of oxygen-rich functional groups on its surface. These chemical groups act as magnets for inorganic contaminants, making the material highly effective for cleaning heavy metals and toxins out of soil and water. In contrast, biochar produced at high temperatures above 700 degrees Celsius develops a much larger surface area and higher electrical conductivity. These traits make high-temperature biochar ideal for advanced technological applications, such as supercapacitors for energy storage and fuel cells. Because apple pomace breaks down at lower temperatures than wood, it requires less energy to develop these beneficial porous structures.

The results of this technological shift are promising for both local ecosystems and industrial sustainability. Experimental data shows that apple pomace biochar can compete with commercial-grade products, removing up to 95 percent of specific chemical fungicides from water sources. Beyond filtration, the material improves soil fertility by neutralizing acidity and providing essential nutrients like calcium, potassium, and phosphorus. This supports a circular bioeconomy where the waste from one industry becomes the raw material for another. The researchers conclude that while challenges remain in scaling up production and standardizing quality, apple pomace biochar is an engineered material with significant potential to support low-carbon technologies and public health. By integrating biochar production into current agricultural frameworks, producers can turn a costly waste problem into a profitable and environmentally friendly solution.

Source: Martins Costa, J., & Forster-Carneiro, T. (2026). Thermochemical conversion of apple pomace into engineered biochar: Production, properties, and technological applications. ACS Engineering Au, 13(2).