Biochar for Wastewater Treatment: An Integrative Review of Feedstocks, Engineering Strategies, Adsorption Mechanisms, and Future Perspectives

ST. Aisyah Humaerah; Sri Magfirah HS

doi:10.32734/jcnar.v8i2.26953

Authors

ST. Aisyah Humaerah Environmental Science Study Program, Faculty of Mathematics and Natural Sciences, Universitas Negeri Makassar, Makassar, 90222, Indonesia
Sri Magfirah HS Environmental Science Study Program, Faculty of Mathematics and Natural Sciences, Universitas Negeri Makassar, Makassar, 90222, Indonesia

DOI:

https://doi.org/10.32734/jcnar.v8i2.26953

Keywords:

Biochar, Wastewater Treatment, Adsorption, Biomass Feedstock, Engineered Biochar

Abstract

The increasing volume and complexity of wastewater have driven the development of effective and sustainable treatment technologies. Biochar is a biomass-based adsorbent with considerable potential for wastewater treatment because its pore characteristics, surface area, functional groups, and mineral composition can be engineered according to target pollutants. This review aims to synthesize the relationships among biomass types, production conditions, activation and modification strategies, physicochemical characteristics, adsorption mechanisms, performance, and application readiness of biochar. Literature was searched through Scopus, ScienceDirect, SpringerLink, Wiley Online Library, Taylor & Francis, MDPI, and selected SINTA-indexed journals for 2021–2026. A total of 40 articles were selected based on relevance, credibility, and information completeness and analyzed using a descriptive-comparative approach. The synthesis indicates that biochar performance results from interactions among feedstock, production conditions, engineering strategies, pollutant properties, and operating conditions. Activation using H₃PO₄, KOH, and NaOH and modification with bentonite, magnetic materials, metal oxides, and carbon-based materials can alter surface characteristics and pollutant affinity. However, increased surface area does not necessarily result in proportional improvements in adsorption performance, highlighting the need to integrate characterization and adsorption data for mechanistic interpretation. Key research gaps include testing standardization, regeneration and stability, validation using real wastewater and multicomponent systems, continuous-flow development and scale-up, and sustainability assessment through Life Cycle Assessment and techno-economic analysis. The review highlights the need for engineered biochar that simultaneously considers performance, stability, safety, process feasibility, and sustainability.

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