Corro E., Antxustegi M., Murua Berrio J., Gonzalez Alriols M., 2024, Residual Lignocellulosic Biomass Based
Activated Biochar: Comparison Between Single and Two Step Thermochemical and Activation Processes, Chemical Engineering Transactions,
109, 217-222 DOI:10.3303/CET24109037

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A recent study investigates the efficiency of activated biochar derived from apple pruning, comparing a single-step thermochemical process to a traditional two-step process. The aim was to explore more streamlined production methods while ensuring high adsorption performance for environmental applications, such as wastewater treatment.

Lignocellulosic biochar, known for its high surface area and porosity, is an effective adsorbent for pollutants. Typically, its production involves two steps: initial pyrolysis of biomass followed by chemical activation, commonly with potassium hydroxide (KOH). This method, while effective, is time-consuming and yields are often low.

In the study, researchers compared the traditional two-step method with a single-step process where the biomass is impregnated with KOH before undergoing a simultaneous pyrolysis and activation. Apple pruning was used as the biomass source due to its lignocellulosic properties. The resulting biochars were characterized using several techniques, including scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), to analyze their surface morphology and functional groups.

The results indicated that the single-step process produced biochar with a higher specific surface area and better porosity distribution than the two-step process. This enhanced the biochar’s adsorption capabilities, achieving nearly complete removal of methylene blue dye from water in a shorter time frame compared to the two-step produced biochar.

The study concludes that the single-step process not only simplifies biochar production but also improves efficiency without compromising adsorption performance. This finding suggests a promising path for scaling up biochar production for industrial applications, offering time and cost savings while maintaining environmental benefits.