The Potential of Waste Phloem Fraction of Quercus cerris Bark in Biochar Production

Abstract

Quercus cerris phloem is a lignocellulosic waste fraction obtained from bark fractionation. Biochars are technologically interesting functional materials that may be produced from lignocellulosic solid materials. This study explores the solid material properties of Quercus cerris phloem, evaluates biochar production from it, and explores its application as an adsorbent. In the first part of the study, thermogravimetric analysis, SEM microscopy observations, FT-IR spectroscopy, and ICP-AES analyses were performed on raw Quercus cerris phloem. In the second part of the study, biochars and activated carbons were produced and their structure, surface functional groups, methylene blue adsorption properties, and specific surface areas were determined. The results showed that Quercus cerris phloem is a lignocellulosic solid material that decomposes in a wide temperature range between 265 and 765 °C. The activation energy of phloem pyrolysis ranged between 82 and 172 kJ mol−1 in pyrolysis. The mineral composition is mainly calcium (88%) and potassium (4%). The biochar yield of Quercus cerris phloem ranged between 28% and 42% at different moderate temperature–time combinations. Raw phloem, phloem biochars, and phloem-activated carbons show high methylene blue removal efficiencies. Methylene blue adsorption follows pseudo-second-order kinetics. The BET surface areas of Quercus cerris phloem-activated carbons varied between 262.1 m2 g−1 and 317.5 m2 g−1.