In a manuscript published in Environmental Research & Technology, researchers Gamze Doğdu Yücetürk, Turgay Pekdemir, Elif Çelik, and Murat Doğru investigated how to transform low-value industrial waste into a high-performance environmental solution. The team successfully took raw biochar, which was obtained as a waste byproduct from an industrial-scale thermal power plant that gasifies pelletized poultry litter, and upgraded it into activated carbon. This conversion route directly aligns with circular economy principles by taking a problematic agricultural residue and processing it into a high-demand commercial product suitable for advanced water treatment applications.

The initial evaluation focused on the physical and chemical characteristics of the industrial biochar baseline. Testing showed that the material possessed an alkaline pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More, negligible moisture content, and a significant ashAsh is the non-combustible inorganic residue that remains after organic matter, like wood or biomass, is completely burned. It consists mainly of minerals and is different from biochar, which is produced through incomplete combustion.   Ash Ash is the residue that remains after the complete More concentration of roughly forty-five percent on a dry basis. These properties confirmed that the precursor material was heavily carbonized during high-temperature industrial gasificationGasification is a high-temperature, thermochemical process that converts carbon-based materials into a gaseous fuel called syngas and solid by-products. It takes place in an oxygen-deficient environment at temperatures typically above 750°C. Unlike combustion, which fully burns material to produce heat and carbon dioxide (CO2​), gasification More and retained sufficient inorganic components to interact with target pollutants. All measured heavy metal boundaries and physical specifications satisfied typical local governmental regulations for material reuse, setting a secure baseline for subsequent activation steps without presenting extra contamination risks.

The research group tested both physical and chemical activation pathways across a temperature spectrum between five hundred fifty and eight hundred degrees Celsius to determine the optimal processing conditions. Chemical techniques involved soaking the biochar in various ratios of phosphoric acid or zinc chloride before thermal treatment. Physical activation relied entirely on exposing the material to a continuous stream of carbon dioxide gas. Across all variations, a processing temperature of eight hundred degrees Celsius systematically produced the highest internal surface areas, as the extreme heat triggers a rapid release of residual volatile matterVolatile matter refers to the organic compounds that are released as gases during the pyrolysis process. These compounds can include methane, hydrogen, and carbon monoxide, which can be captured and used as fuel or further processed into other valuable products.   More and expands the internal pore framework.

The results demonstrated that physical activation with carbon dioxide at eight hundred degrees Celsius yielded an exceptional product without requiring any added chemicals. This specific material developed a high-level pore network because the carbon dioxide reacts directly with carbon atoms in the biochar matrix, removing internal compounds to etch out new microscopic voids. Structural analysis via infrared spectroscopy and X-ray diffraction verified that the surface of the physically activated carbon retained active oxygen-containing functional groups and underwent distinct crystal transformations that are highly advantageous for chemical binding.

Adsorption performance trials revealed that the carbon dioxide-activated carbon was incredibly efficient at capturing organic pollutants from aqueous solutions, outperforming both the raw biochar and the chemically treated samples. In batch water treatment tests, the maximum adsorption capacity for methylene blue dye reached 119.3 milligrams per gram using the physically activated material. For comparison, the phosphoric acid and zinc chloride versions reached maximum capacities of only 48.6 and 75.5 milligrams per gram, respectively. The pollutant uptake matched a single-layer binding model, proving that the processed surfaces provided a highly uniform and accessible grid of active capture sites.

Kinetic modeling further established that the adsorption rate followed a strict second-order reaction mechanism, indicating stable chemical interactions between the dye molecules and the carbon surface. The superior performance of the gasification-derived material over traditional laboratory-synthesized alternatives is likely due to the high-level pore development initiated during initial plant gasification, which avoids pore-clogging issues. Ultimately, the study confirms that utilizing zero-value industrial biochar as a precursor is a highly feasible, cost-effective, and sustainable method for scaling up waste recycling into valuable commercial adsorbents.

Source: Doğdu Yücetürk, G., Pekdemir, T., Çelik, E., & Doğru, M. (2026). Valorisation of biochar from poultry litter power plant to activated carbon: Production, characterisation, and application. Environmental Research & Technology, 9(3), 520-534.