Low-temperature biochars from cork-rich and phloem-rich wastes: fuel, leaching, and methylene blue adsorption properties

Waste cork and phloem fractions from the bark of Turkey oak (Quercus cerris) were subject to low-temperature pyrolysis between 250 and 325 degrees C and residence times of 30 or 60 min. The fuel, leaching, and methylene blue adsorption properties of the produced biochars were evaluated for the first time. The results indicate that cork and phloem containing bark fractions have a promising potential for the production of biochars. The pyrolysis process reduces the bark wastes and contributes to their efficient use. The cork and phloem biochars produced above 300 degrees C showed promising H/C and O/C atomic ratios that were comparable with lignite. Methylene blue adsorption on cork and phloem biochars was inversely affected by pyrolysis temperature and residence time. Activated carbons for soil amendment applications may be produced from the biochars via a steam activation method with optimum temperature and residence time of approximately 300 degrees C and 30 min in order to harness the nutrient release while avoiding the potential of toxicity from phenolic leaching.