Skic, K., Adamczuk, A., Gryta, A. et al. Surface areas and adsorption energies of biochars estimated from nitrogen and water vapour adsorption isotherms. Sci Rep14, 30362 (2024). https://doi.org/10.1038/s41598-024-81030-9

BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More, a carbon-rich material derived from biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More, is gaining attention for its versatility in agriculture, environmental management, and pollution control. Its efficiency depends on key properties like surface area and adsorption capacity. A recent study compares two common methods for evaluating biochar’s surface characteristics: nitrogen and water vapour adsorption.

The research highlights limitations in the traditional nitrogen adsorption method, which often underestimates biochar’s surface area due to its inability to detect smaller pores and surface complexities. Nitrogen’s slow diffusion and large molecular size can lead to inaccuracies, particularly in highly microporous or ash-laden biochars.

In contrast, water vapour adsorption provides a more accurate representation of biochar’s surface area and adsorption energy. Water molecules, being smaller and polar, can access sites nitrogen cannot, making this method more relevant for applications like soil water retention and cation exchange. For example, biochars produced at higher pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More temperatures exhibit reduced water vapour surface areas, aligning with the loss of oxygenated functional groups and increased structural rigidity.

This study suggests a shift towards water vapour adsorption for evaluating biochar properties, especially for environmental applications. By accurately measuring surface areas, this approach supports better understanding and optimization of biochar’s roles, from improving soil fertility to filtering pollutants.

Understanding these differences could refine biochar design and application, ensuring its potential is fully realized across various industries.