Biochar for Water Pollution Control: From Sensing to Decontamination

Biochar, a biologically originated carbon-rich material derived from the oxygen-limited pyrolysis of biomass, is usually added to the soil for its enrichment, increasing its water-holding capacity and pH. This revolutionary material thus contributes to a reduction in the overall environmental impact and mitigation of climate change. Due to the beneficial properties of this material, especially for electrochemical applications (large active surface area, conductivity, etc.), biochar demonstrates an extremely high capacity for the adsorption and detection of micropollutants simultaneously. However, finding the optimal conditions for the adsorptive and electrochemical properties of prepared biochar-based sensors is crucial. The adsorption efficiency should be sufficient to remove pollutants, even from complex matrices; on the other hand, the electrochemical properties, such as conductivity and charge transfer resistance, are key factors concerning the sensing ability. Therefore, the balanced design of biochar can ensure both the usability and the effectiveness of sensing. To enhance levels of electroactivity that are already high, the pre- or post-modification of biochar can be performed. Such recycled carbon-based materials could be promising candidates among other electrochemical sensing platforms. In this study, different biochar modifications are presented. Utilizing important biochar properties, it should be possible to create a bifunctional platform for removing micropollutants from water systems and simultaneously confirming purification levels via their detection. We reviewed the use of biochar-based materials for the effective removal of micropollutants and the methods for their detection in water matrices.