Publication
Development of an Acacia-based biorefinery – an advanced system for biomass valorization and environmental sustainability
| Summary: | Acacia dealbata is an invasive species whose spreading must be controlled but with industrial applica-tions as a source of concretes, tannins, wood materials and biofuels. Both removal operations and in-dustrial applications generate biomass wastes that could be further valorized. The main goal of this thesis was to study the integral exploitation of A. dealbata biomass (flowers, leaves, twigs, wood, and bark) from a biorefinery perspective. Extraction of terpenic and phenolic components from flowers collectd at different locations, was evaluated using different solvents and extraction methods. Lipophilic extracts (absolutes) were charac-terized by SPME-GC-TOFMS showing the presence of organic acids, hydrocarbons and pentacyclic triter-penes. The phenolic fraction obtained from flowers had high levels of total phenolics and its character-ization by HPLC-DAD and HPLC-DAD-MS/MS revealed the presence of flavonoid glycosides with rele-vant biological activities. Polar extracts obtained from leaves, twigs, wood, and bark showed high levels of total phenolics, flavonoids and proanthocyanidins. Leaves were also a source of lipophilic extracts rich in phytol, lupenone and lupeol. All phenolic extracts presented antioxidant properties (in DPPH and FRAP tests) and antimicrobial activity against gram-positive bacteria. The composition and properties of raw and spent biomass fractions were evaluated to validate their use as biofuels after extraction with solvents. Torrefaction and hydrothermal carbonization were used to convert these spent biomasses into biochars and hydrochars with improved fuel properties. Spent biomasses and corresponding chars were tested as adsorbents for cationic and anionic dyes, reaching removal efficiencies higher than 90%. The incorporation of the different Acacia biomass fractions in mortars to replace fillers was tested as a con-tribution to incorporate renewable resources in building materials. The results obtained demonstrate multiple conversion pathways that can be used to valorise Aca-cia biomass producing energy and various marketable products, thus promoting bioeconomy and the sustainability of the forestry sector. |
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| Main Authors: | Correia, Ricardo José Gorjão |
| Subject: | Acacia dealbata absolutes phenolics biomass torrefaction hydrothermal carbonization |
| Year: | 2023 |
| Country: | Portugal |
| Document type: | doctoral thesis |
| Access type: | open access |
| Associated institution: | Universidade Nova de Lisboa |
| Language: | English |
| Origin: | Repositório Institucional da UNL |
| Summary: | Acacia dealbata is an invasive species whose spreading must be controlled but with industrial applica-tions as a source of concretes, tannins, wood materials and biofuels. Both removal operations and in-dustrial applications generate biomass wastes that could be further valorized. The main goal of this thesis was to study the integral exploitation of A. dealbata biomass (flowers, leaves, twigs, wood, and bark) from a biorefinery perspective. Extraction of terpenic and phenolic components from flowers collectd at different locations, was evaluated using different solvents and extraction methods. Lipophilic extracts (absolutes) were charac-terized by SPME-GC-TOFMS showing the presence of organic acids, hydrocarbons and pentacyclic triter-penes. The phenolic fraction obtained from flowers had high levels of total phenolics and its character-ization by HPLC-DAD and HPLC-DAD-MS/MS revealed the presence of flavonoid glycosides with rele-vant biological activities. Polar extracts obtained from leaves, twigs, wood, and bark showed high levels of total phenolics, flavonoids and proanthocyanidins. Leaves were also a source of lipophilic extracts rich in phytol, lupenone and lupeol. All phenolic extracts presented antioxidant properties (in DPPH and FRAP tests) and antimicrobial activity against gram-positive bacteria. The composition and properties of raw and spent biomass fractions were evaluated to validate their use as biofuels after extraction with solvents. Torrefaction and hydrothermal carbonization were used to convert these spent biomasses into biochars and hydrochars with improved fuel properties. Spent biomasses and corresponding chars were tested as adsorbents for cationic and anionic dyes, reaching removal efficiencies higher than 90%. The incorporation of the different Acacia biomass fractions in mortars to replace fillers was tested as a con-tribution to incorporate renewable resources in building materials. The results obtained demonstrate multiple conversion pathways that can be used to valorise Aca-cia biomass producing energy and various marketable products, thus promoting bioeconomy and the sustainability of the forestry sector. |
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