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, a carbon-rich material derived from various sources, is gaining attention for its abundance and cost-effectiveness. In the journal Molecules, Chang et al., explored how to optimize the production of biochar from sunflower straw using potassium hydroxide (KOH) activation. KOH is a strong alkali activator that can alter biochar’s surface and microstructure, resulting in a large specific surface area (SSA) and a rich pore structure. This study analyzed the impact of different preparation conditions on the properties and structure of the biochar derived from sunflower straw.  

The researchers found that specific activation conditions significantly influence the final biochar product. The optimal conditions for preparing the biochar involved an impregnation ratio (KOH to sunflower straw biochar) of 2:1, an activation time of 2 hours, and an activation temperature of 900°C. Biochar produced under these conditions exhibited a rougher surface, increased aromaticity and graphitization, and a high SSA of 594.655 m2/g.  

The study also examined how varying the impregnation ratio, activation temperature, and activation time affected the biochar’s yield, water absorption, and elemental composition. For instance, increasing the impregnation ratio from 0.5:1 to 3:1 decreased the biochar yield from 56.23% to 47.63%, while a 2:1 ratio resulted in the highest SSA. Increasing the activation temperature from 600°C to 900°C also reduced the yield but increased the SSA, with biochar activated at 900°C showing the highest SSA (1032.361 m2/g).  

In conclusion, the research provides valuable insights into optimizing biochar preparation from sunflower straw, which could promote its high-value utilization in energy and environmental applications.  

SOURCE: Chang, S., Wang, L.; Yao, L.. Properties of Sunflower Straw Biochar Activated Using Potassium Hydroxide. Molecules 2025, 30, 1332.