Speakers

Biography

Paul Luzuriaga is a PhD candidate in Environmental Engineering from the University of Calgary and a Doctor in Business Administration from Florida International University, with about 20 years of experience in forest research and soil regeneration.

Abstract

Prosopis pallida, also known as Mesquite or Algarrobo in America, is considered a useful species for depleted soils, especially in arid or desertic climates, and of particular interest for urban forestry programs in areas lacking precipitation or irrigation. While the trees are of rapid growth, they require thinning, pruning, and other cultural practices to increase efficiency in soil restoration and carbon fixation. Those tree management activities produce large quantities of wood waste, normally left in the field for decomposition or burned out, turning into an economic inefficiency and an environmental nuance when previously fixated CO2 is released.

As biochar production from those wood wastes is being studied, a secondary approach might include the valorization of polyphenols and tannins before their carbonization due to their potential high-value properties.

This report analyzed three extraction methods in lab conditions on wood pulp and bark separately—cellulose content and total polyphenols, total tannins, and condensed tannins. Solvents included 4% sodium sulfite, distilled water, and methanol-hydrochloric acid solution.

The extractive protocol, type of solvent, temperature, extraction velocity, and sample freshness can greatly affect the quantity and quality of the extracted products. The test results showed a relevant difference in tannins content between the bark and the wood pulp, recovering on average 33% content on 59% extraction efficiency and 18% content on 47% extraction efficiency, respectively. Also, in condensed tannins, 13% were condensed tannins in bark, while less than 1% were in wood pulp, and cellulose content and structure seemed unchanged after tannins extraction.

Dried wood in ambient conditions under shelter seemed to concentrate tannins, increasing extraction efficiency after 60 days since wood collection.

For scaling up, further analysis of uncharacterized compounds needs to be performed to define extraction methods and long-term efficiencies better.