Use of biochar in water and wastewater treatment: a bibliometric analysis and state-of-the-art review

Abstract

Background: Biochar has emerged as a sustainable and efficient alternative for water and wastewater treatment due to its high surface area, porosity, chemical stability, and adsorption capacity. Over time, numerous studies have proposed methods for removing contaminants from water and wastewater to enable their reuse in accordance with Sustainable Development Goals (SDGs) 6 and 14. Among the techniques reported as effective in this context is the use of biochar. Therefore, the aim of the present study was to examine the state of the art and current trends regarding the use of biochar in water and wastewater treatment. To achieve this, a bibliometric analysis was conducted using the Scopus scientific database to identify the research landscape involving biochar for water and wastewater treatment.
Results: The use of residual agroforestry biomass for biochar production was predominant, including coffee husks, açaí seeds, bamboo, wood, rice husks, corn cobs, and forest residues. In addition, muffle furnaces were the most commonly used systems in thermal degradation processes. The pharmaceutical and textile industries, followed by water treatment facilities, were identified as the sectors with the greatest research interest involving biochar-based adsorbents.
Conclusions: Biochar demonstrated significant potential and efficiency for water and wastewater treatment due to its performance in removing contaminants such as pharmaceutical compounds, dyes, heavy metals, and emerging micropollutants. The successful removal of pollutants was mainly attributed to the adsorption mechanism associated with biochar, with improved performance observed after chemical activation. Therefore, biochar stands out not only as an adsorbent material, but also as a technology aligned with environmental remediation strategies, waste valorization, and sustainable water resource management.