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2025 Vol.57, Issue 6 Preview Page

Original Paper

Study on the Valorization of Oak Bark Biomass - Part II: Organosolv Pulping of Bark Residue after Tannin Extraction
Sa Rang Choi1
,
Jung Myoung Lee2†
1Department of Wood and Paper Science, Kyungpook National University, Lecturer
2Department of Wood and Paper Science, Kyungpook National University, Professor
†Corresponding Author: E-mail: jmylee@knu.ac.kr (Address: Department of Wood and Paper Science, Kyungpook National University, Daegu, 41566, Republic of Korea)
30 December 2025. pp. 75-84
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Abstract

Bark, a significant byproduct of the wood industry accounting for 10–20% of log weight, is typically utilized for low-value applications because of its high ash and lignin contents. Nevertheless, it remains a rich source of cellulose and hemicellulose, offering potential as a high-value bioproduct feedstock through appropriate pretreatment and pulping. In this study, tannin-extracted oak bark residues were subjected to organosolv pulping using either acidic (H2SO4) or alkaline (NaOH) catalysts. The pulp yields were 39.4% and 45.6% under Acid 60 (120°C, 60 min) and Alkali 90 (120°C, 90 min) conditions, respectively. Acidic pulping induced partial hydrolysis of polysaccharides, whereas alkaline treatment facilitated lignin–hemicellulose cleavage and improved carbohydrate preservation. Lignin recovered from black liquor under Acid 60 conditions exhibited the highest purity (82.8%) and recovery yield (37.3%). The resulting pulps were directly micronized by homogenization to produce well-dispersed microfibers without additional pretreatment. Overall, these findings demonstrate that tannin-extracted bark residues are promising precursors for microfibers suitable as bio-based fillers and compatibilizers, contributing to the sustainable valorization of underutilized forest biomass.

Keywords
Unused biomass
oak bark
valorization of bark
organosolv pulp
bark-based microfiber
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Information
  • Publisher :Korea Technical Association of The Pulp and Paper Industry
  • Publisher(Ko) :한국펄프종이공학회
  • Journal Title :Journal of Korea TAPPI
  • Journal Title(Ko) :펄프종이기술
  • Volume : 57
  • No :6
  • Pages :75-84
  • Received Date : 2025-11-03
  • Revised Date : 2025-11-19
  • Accepted Date : 2025-11-19
  • DOI :https://doi.org/10.7584/JKTAPPI.2025.12.57.6.75
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