In a recent bibliometric analysis published in 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, Mbezele Junior Yannick Ngaba, Olive Mekontchou Yemele, Bin Hu, and Heinz Rennenberg meticulously examined the current trends and future perspectives of biochar application as a green clean-up method. Their comprehensive study sheds light on the remarkable growth and diversification of biochar research over the past two decades.

Biochar has emerged as a cutting-edge solution for environmental remediation, offering a sustainable alternative to traditional methods. Its versatility extends beyond conventional uses in fuel and carbon sequestration, now encompassing enhanced soil functionality, water treatment, air pollution control, and waste management. The authors note that since 2010, the global application of 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 has surged, with over 250 research reports highlighting its exceptional potential in improving soil properties like water retention, nutrient cycling, and fostering beneficial microbial communities.

The bibliometric analysis, encompassing 7076 records from the Web of Science Core Collection between 2007 and 2023, reveals a dramatic increase in research interest. The growth can be distinctly divided into two stages: from 2007 to 2017, publications accounted for only 21% of the total, while the period from 2018 to 2023 saw an exponential growth, accounting for 71% of all publications. The annual growth rate accelerated significantly, from 125% per year in the initial stage to an impressive 1099% per year in the latter stage, underscoring the escalating recognition of biochar as a critical green clean-up solution.

Research on biochar spans 95 core categories recognized by the Web of Science, emphasizing its interdisciplinary nature. The top 10 categories include environmental sciences, soil sciences, environmental engineering, agronomy, and plant sciences. This diverse application spectrum is driving a notable shift in environmental management approaches.

Geographically, China, the USA, and Germany are the primary contributors to biochar application research. China leads significantly in both publication volume (2163 articles) and citations (69,882), as well as in international collaborations, with 61 links to other countries. This prominence is largely attributed to factors such as funding availability, existing infrastructure, and supportive government policies.

Key research hotspots identified include biochar’s use as a soil amendment, its application in water and air pollution control, and its role in waste management and bioenergy production. As a soil amendment, biochar improves water retention, nutrient cycling, and microbial communities. In wastewater treatment, biochar enhances water quality by providing a medium for microbial degradation of pollutants. For air pollution, it effectively absorbs organic gases and particulate matter, and its acidic functional groups aid in ammonia retention. The integration of biochar with other green clean-up methods, such as phytoremediationThis is a technique that uses plants to clean up contaminated soil or water. Biochar can enhance phytoremediation by improving soil conditions and promoting plant growth, allowing plants to absorb and break down pollutants more effectively.   More and microbial degradation, is also gaining traction, enhancing contaminant removal and promoting soil carbon sequestration.

Emerging trends highlight an increased focus on field-based studies, exploring biochar’s ability to remove emerging contaminants like pharmaceuticals, and its novel use in green construction materials. Advanced techniques like scanning electron microscopy (SEM) and X-ray diffraction (XRD) are being employed to investigate molecular and elemental changes in soil after biochar application, offering a new perspective on biochar research. Innovative production methods like co-pyrolysis, microwave 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, and plasma-arc pyrolysis are also being explored to enhance biochar quality and efficiency.

Looking ahead, future research should focus on clarifying the precise definition of biochar as a soil amendment, bridging the gap between soil science and plant molecular biology, and establishing robust regulatory frameworks and economic models to facilitate large-scale adoption. Continued interdisciplinary collaboration is crucial to fully realize biochar’s potential as a versatile tool for sustainable soil management and pollution mitigation.

Source: Ngaba, M. J. Y., Yemele, O. M., Hu, B., & Rennenberg, H. (2025). Biochar application as a green clean-up method: bibliometric analysis of current trends and future perspectives. Biochar, 7(83).