Characterization of Formacell Lignin Derived from Black Liquor as a Potential Green Additive for Advanced Biocomposites

Sri Hidayati^1,*, Eugenia Fonny Budiyanto¹, Hadi Saputra¹, Sutopo Hadi¹, Apri Heri Iswanto^2,3, Nissa Nurfajrin Solihat⁴, Petar Antov⁵, Lee Seng Hua^6,7, Widya Fatriasari^4,8, Mohd. Sapuan Salit⁹
1 Agricultural Product Technology Department, Faculty of Agriculture, The University of Lampung, Jl. Sumantri Brojonegoro No. 1, Bandar Lampung, Indonesia
2 Department of Forest Product, Faculty of Forestry, Universitas Sumatera Utara, Kampus USU Padang Bulan, North Sumatra, Indonesia
3 JATI-Sumatran Forestry Analysis Study Center, Jl. Tridharma Ujung No. 1, Kampus USU, Medan, North Sumatra, Indonesia
4 Research Center for Biomass and Bioproducts, National Research and Innovation Agency (BRIN), Jl. Raya Bogor, Cibinong, Indonesia
5 Faculty of Forest Industry, University of Forestry, Sofia, Bulgaria
6 Department of Wood Industry, Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM), Cawangan Pahang Kampus Jengka, Lintasan Semarak, Bandar Jengka, Malaysia
7 Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, Selangor, Malaysia
8 Research Collaboration Center for Marine Biomaterials, Jl. Ir. Sukarno, Jatinangor, Sumedang, West Java, Indonesia
9 Advanced Engineering Materials and Composites Research Centre, Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, Selangor, Malaysia
* Corresponding Author: Sri Hidayati. Email: srihidayati.unila@gmail.com
(This article belongs to this Special Issue: Advances in Eco-friendly Wood-Based Composites: Design, Manufacturing, Properties and Applications)

Journal of Renewable Materials https://doi.org/10.32604/jrm.2023.027579

Received 04 November 2022; Accepted 19 December 2022; Published online 31 January 2023

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Abstract

Black liquor is obtained as a by-product of the pulping process, which is used to convert biomass into pulp by removing lignin, hemicelluloses and other extractives from wood to free cellulose fibers. Lignin represents a major constituent in black liquor, with quantities varying from 20% to 30%, of which a very low share is used for manufacturing value-added products, while the rest is mainly burned for energy purposes, thus underestimating its great potential as a raw material. Therefore, it is essential to establish new isolation and extraction methods to increase lignin valorization in the development of bio-based chemicals. The aim of this research work was to determine the effect of KOH or ethanol concentration as an isolation agent on lignin yields and the chemical characteristics of lignin isolated from formacell black liquor of oil palm empty fruit bunch (OPEFB). Isolation of lignin was carried out using KOH with various concentrations ranging from 5% to 15% (w/v). Ethanol was also used to precipitate lignin from black liquor at concentrations varying from 5% to 30% (v/v). The results obtained showed that the addition of KOH solution at 12.5% and 15% concentrations resulted in better lignin yield and chemical properties of lignin, i.e., pH values of 3.86 and 4.27, lignin yield of 12.78% and 14.95%, methoxyl content of 11.33% and 10.13%, and lignin equivalent weights of 476.25 and 427.03, respectively. Due to its phenolic structure and rich functional groups that are favorable for modifications, lignin has the potential to be used as a green additive in the development of advanced biocomposite products in various applications to replace current fossil fuel-based material, ranging from fillers, fire retardants, formaldehyde scavengers, carbon fibers, aerogels, and wood adhesives.