Life cycle assessment of tannin extraction from spruce bark

Abstract

(1)Tannins have shown antifungal effects and have been considered a potential natural compound for wood preservation. Extracts produced from softwood bark contain both tannins and non-tannin compounds, which may reduce the effectiveness of tannin used as a wood preservative. The purpose of this research is to study the environmental impact of hot water extraction, identify the hot spots within the tannin cradle-to-gate life cycle and give suggestions to optimize its environmental profile. Different extraction and postextraction scenarios of tannin production are compared using the life-cycle assessment method. Experiments were designed to study the tannin yield under different extraction scenarios; the post-extraction scenario analysis was based on literature review. The results show that the extract drying process is the primary contributor to the environmental impact of tannin production. Both preliminary cold water extraction and ultrafiltration after extraction are beneficial as they have fewer non-tannin compounds in the final products; however, preliminary cold water extraction had a considerably lower environmental performance. Successive extractions using fresh water at each cycle increased the total tannin yield, but increased the environmental burden. Using only evaporation to obtain a desired tannin concentration is not environmentally efficient. This paper provides a quantified environmental analysis for the development of tannin-treated wood products and discusses the different tannin extraction scenarios from an environmental point of view.

Life cycle assessment of polyphenols extraction processes from waste biomass

“…functional units, system boundaries, product allocation and impact assessment methods) and the next citations are reported only for scaling purposes and further comparisons would not be correct. For example, considering weight as a functional unit, Ding et al 22 reported approximately 4 kg CO 2 eq per kg of extracted tannins at laboratory scale, while Modahl et al 18 reported approximatively 1 kg CO 2 eq per kg of extracted vanillin (at full industrial scale).…”

“…In this field, LCA has been mainly used to evaluate full-scale bioenergy production (mainly bio-ethanol 18 , biogas 19,20 , jet fuel 21 ) and to a lesser extent the production of chemicals like polysaccharides 5 or tannins 22 .…”

“…There are only few LCA studies that have approached the environmental impacts of polyphenols extraction from bark. For example, Ding et al 22 have evaluated the environmental impacts of different scenarios related to tannin extraction from spruce bark (hot and cold water extraction) and have concluded that increasing the tannin yield (by increasing the extraction steps) leads to increased environmental impacts. This analysis was focused on energy-related impacts which were strongly linked to the structure of the electricity mix.…”

Multifunctional comparison of different management strategies in boreal forests

“…The anionic and cationic charge density of tannins and cationic cellulose nanocrystals (CCNC) 104 were determined using polyelectrolyte titration with particle charge detector (PCD). 0.01% 105 (w/w) tannin and cationic cellulose nanocrystals solution were prepared at different pH (3)(4)(5)(6)(7)(8)(9)(10) and titrated with poly-diallyldimethylammonium chloride and sodium polyelectrolyte sulphonate. All dilutions were done using same buffer solutions used for tannin and nanocrystal sample preparation.…”

“…Proanthocyanidins such as tannins and other flavonoids are a group of bio-based chemicals traditionally extracted from plant seeds, berry or fruit skins, tree heartwood or bark and novel means to valorize these especially from industrial side streams are ongoing [1][2][3][4][5] . These phenolic, secondary metabolic compounds in plants have traditionally been used in leather industry due to the protein binding capacity and more recently in colloidal complexes intended for food, pharma, 6 chemical and wood product industries [6][7][8][9] .…”