In a recent comprehensive bibliometric analysis published in Biofuels, Bioproducts & Biorefining, Jean Agustin Velasquez-Pinas and co-authors provide an insightful overview of the rapidly expanding field of 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 research. Their study, covering the period from 2019 to 2023, reveals an impressive 20,041 articles and reviews published, underscoring the scientific community’s increasing interest in this versatile material.

The analysis highlights China as the unequivocal leader in biochar research and development, accounting for a significant 57% (11,484 publications) of all publications during the study period. This dwarfs the contributions of other leading nations, such as the USA (10% with 1,958 publications) and India (7% with 1,488 publications). This concentrated research effort in China suggests a strategic focus on biochar’s potential applications within the country. Environmental science and ecology emerged as the dominant research areas, followed by engineering and agriculture, indicating a clear trend towards optimizing processes and applying biochar as a soil amendmentA soil amendment is any material added to the soil to enhance its physical or chemical properties, improving its suitability for plant growth. Biochar is considered a soil amendment as it can improve soil structure, water retention, nutrient availability, and microbial activity.   More.

The surge in biochar research isn’t a new phenomenon, but rather an acceleration of a long-term trend. Since 2006, there has been a notable increase in publications, with an astounding 72% average annual growth between 2011 and 2013 alone. Early research, from 1974 to 1997, explored biochar’s use in medical equipment and wastewater treatment. Later, between 1998 and 2006, the scope broadened to include analytical chemistry, energy, and multidisciplinary studies, with keywords like “sustainability” and “climate change” beginning to appear in correlation with biochar.

One of the key findings of the study is the prominence of 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 as the preferred technology for biochar production. This thermochemical process, which involves heating 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 in the absence of oxygen, is favored for its ability to simultaneously produce biochar, bio-oil, and syngasSyngas, or synthesis gas, is a fuel gas mixture consisting primarily of hydrogen and carbon monoxide. It is produced during gasification and can be used as a fuel source or as a feedstock for producing other chemicals and fuels.   More. While other methods like gasificationGasification is a high-temperature, thermochemical process that converts carbon-based materials into a gaseous fuel called syngas and solid by-products. It takes place in an oxygen-deficient environment at temperatures typically above 750°C. Unlike combustion, which fully burns material to produce heat and carbon dioxide (CO2​), gasification More and torrefaction are also explored, pyrolysis has taken the lead. The type of biomass used and the operational conditions, such as temperature and residence timeResidence time refers to the duration that the biomass is heated during the pyrolysis process. The residence time can influence the properties of the biochar produced.   More, significantly influence the final characteristics of the biochar. For instance, slow pyrolysis, operating at 300 to 500∘C with longer residence times, prioritizes char production, yielding up to 20-50% biochar.

Biochar’s diverse applications are a major driver of this research boom. Adsorption has gained significant attention, particularly for remediating contaminated soils and water. Studies show its effectiveness in removing heavy metals like copper (Cu) and cadmium (Cd) from soil, reducing their uptake by plants. Beyond soil remediation, biochar is increasingly recognized for its role in anaerobic digestion within the circular economy, with studies showing an increase in methane yield by as much as 17% in some cases. Its ability to mitigate greenhouse gas emissions, particularly carbon sequestration, is another critical application. The persistence of biochar carbon in the environment, with some studies estimating a stable lifespan of 556 years for 97% of biochar, directly contributes to long-term carbon sequestration.

The most cited research articles further underscore these applications. The top-cited study focuses on biochar-based nanocomposites for photocatalytic removal of tetracycline hydrochloride from contaminated water. Other highly cited works explore N-doped biochar for activating peroxydisulfate in degrading sulfadiazine, the impact of zinc and iron oxide nanoparticles on wheat growth in cadmium-contaminated soil, and the development of metal-free biochar catalysts for degradation.

The increasing recognition of biochar’s potential in various sectors, from agriculture to waste management and energy production, positions it as a crucial material for advancing sustainability goals and fostering a circular bioeconomy. Future research is expected to focus on optimizing biochar production for specific applications and scaling up these technologies for wider adoption.

Source: Velasquez-Pinas, J. A., Ghofrani-Isfahani, P., Yepes Maya, D., Ravenni, G., Castro, L. E. N., Angelidaki, I., & Forster-Carneiro, T. (2025). Biochar in the circular bioeconomy: a bibliometric analysis of technologies, applications, and trends. Biofuels, Bioproducts & Biorefining, 19(X), 1–37.