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13 pages, 2390 KiB

Open AccessArticle

Use of Invasive Acacia Biomass to Produce Biochar and Solid Biofuels

by Óscar González-Prieto and Luis Ortiz Torres

Appl. Sci. 2025, 15(10), 5755; https://doi.org/10.3390/app15105755 - 21 May 2025

Viewed by 38

Abstract

This study focuses on the production of high-density solid biofuels and high-fixed-carbon biochar from two invasive acacia species harvested in a protected area in Northwestern Spain, thereby contributing to its silviculture management challenge. It is possible to transform the initial biomass into briquettes [...] Read more.

This study focuses on the production of high-density solid biofuels and high-fixed-carbon biochar from two invasive acacia species harvested in a protected area in Northwestern Spain, thereby contributing to its silviculture management challenge. It is possible to transform the initial biomass into briquettes and pellets reaching high densified values above 1300 kg/m³ and 500 kg/m³, respectively. Using thermochemical conversion processes in a simple double chamber oven, a biochar was obtained with a fixed carbon of 66%. Several parameters were analyzed and compared between the original biomass and the resulting products. The results show that an added value could be achieved without applying a complex system to transform, starting from residual biomass from invasive species. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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13 pages, 1669 KiB

Open AccessArticle

Effluent from Winery Waste Biorefinery: A Strategic Input for Biomass Generation with Different Objectives to Add Value in Arid Regions

by Pedro Federico Rizzo, Germán Darío Aguado, Iván Funes-Pinter, Laura Elizabeth Martinez, Florencia Noemí Ferrari, Federico De Biazi, Pablo Martín, Gustavo Flores, Antoni Sánchez and Ernesto Martin Uliarte

Appl. Sci. 2025, 15(3), 1435; https://doi.org/10.3390/app15031435 - 30 Jan 2025

Viewed by 835

Abstract

Agro-industrial activities generate significant amounts of organic waste and a variety of effluents thus posing environmental challenges. Viticulture in Argentina, which covered 204,847 ha in 2023, faces water scarcity as a limiting factor conditioning its production. This industry produces large volumes of grape [...] Read more.

Agro-industrial activities generate significant amounts of organic waste and a variety of effluents thus posing environmental challenges. Viticulture in Argentina, which covered 204,847 ha in 2023, faces water scarcity as a limiting factor conditioning its production. This industry produces large volumes of grape marc, sediments, and stalks, which can be valorised into products like alcohol, tartaric acid, and compost. However, these valorisation processes generate effluents with high organic load and salinity, further stressing water resources. This study explores the potential of utilising these effluents to cultivate plant biomass in arid regions (sorghum or perennial pasture), which could serve as bioenergy, animal feed, or composting co-substrates, contributing to circular bioeconomy principles. The combined use of effluent as a water resource and the sowing of sorghum and pasture increased soil organic matter content and led to a slight reduction in pH (depth: 0.30–0.60 m) compared to the control treatment. The sorghum plots showed better establishment and higher dry biomass yield (32.6 Tn/ha) compared to the pasture plots (6.5 Tn/ha). Sorghum demonstrated better tolerance to saline soils and high salinity effluents, aligning with previous studies. Although pasture had a lower biomass yield, it was more efficient in nutrient uptake, concentrating more NPK, ash, and soluble salts. Sorghum’s higher yield compensated for its lower nutrient concentration. For biomass production, sorghum is preferable, but if nutrient capture from effluents is prioritised, summer polyphytic pastures are more suitable. These results suggest that the final selection between plant biomass alternatives highly depends on whether the goal is biomass generation or nutrient capture. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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14 pages, 1302 KiB

Open AccessArticle

Characterization of Congolese Woody Biomass and Its Potential as a Bioenergy Source

by Maryse D. Nkoua Ngavouka, Tania S. Mayala, Dick H. Douma, Aaron E. Brown, James M. Hammerton, Andrew B. Ross, Gilbert Nsongola, Bernard M’Passi-Mabiala and Jon C. Lovett

Appl. Sci. 2025, 15(1), 371; https://doi.org/10.3390/app15010371 - 2 Jan 2025

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Abstract

This study assesses and characterizes six woody biomass (WB) species commonly harvested in the Republic of Congo: Millettia laurentii (WB1), Millettia eetveldeana (WB2), Hymenocardia ulmoides (WB3), Markhamia tomentosa (WB4), Pentaclethra eetveldeana (WB5), and Hymenocardia acida (WB6). Characterization was performed using proximate analysis with [...] Read more.

This study assesses and characterizes six woody biomass (WB) species commonly harvested in the Republic of Congo: Millettia laurentii (WB1), Millettia eetveldeana (WB2), Hymenocardia ulmoides (WB3), Markhamia tomentosa (WB4), Pentaclethra eetveldeana (WB5), and Hymenocardia acida (WB6). Characterization was performed using proximate analysis with a Thermo Gravimetric Analyser (TGA), ultimate analysis with a CHNS Analyser, higher heating value (HHV) determination, metal content analysis by X-ray fluorescence (XRF), and aboveground biomass (AGB) estimation. The proximate analysis results showed that volatile matter varied between 74.6% and 77.3%, while the ultimate analysis indicated that carbon content ranged from 43% to 46%, with low nitrogen content. XRF analysis revealed low levels of heavy metals in all samples. The HHV results, using three models (Dulong’s equation, Friedl, and proximate analysis), showed higher values with Friedl’s method (17.3–18.2 MJ/kg) and proximate analysis (15.26–19.23 MJ/kg) compared to Dulong’s equation (13.9–14.9 MJ/kg). Savannah biomass (WB6) exhibited high AGB (7.28 t), 14.55 t/ha, and carbon stock (7.28 t). Compared to forest biomass, savannah biomass presents a higher potential for bioenergy production. Minimal statistical analysis of wood biomass showed that parameters such as volatile matter (VM), carbon (C), hydrogen (H), and calculated HHV have low variability, suggesting the biomass is relatively homogeneous. However, moisture and nitrogen showed significant standard deviations, indicating variability in storage conditions or sample nature. Statistical analysis of forest biomass estimation revealed different mean values for diameter, AGB (t and t/ha), and carbon stock, with high standard deviations, indicating a heterogeneous forest with both young and mature trees. These analyses and estimates indicate that these WB species are suitable for biofuel and bioenergy production using gasification, pyrolysis, and combustion processes. Among these thermochemical processes, gasification is the most efficient compared to combustion and pyrolysis. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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16 pages, 2397 KiB

Open AccessFeature PaperArticle

Characterization of Several 2-Ethylhexyl Nitrates with Vegetable Oil (Castor or Sunflower Oil) Blends in Triple Blends with Diesel, Working as Advanced Biofuels in C.I. Diesel Engines

by Rafael Estevez, Francisco J. López-Tenllado, Vicente Montes, Antonio A. Romero, Felipa M. Bautista and Diego Luna

Appl. Sci. 2024, 14(24), 11968; https://doi.org/10.3390/app142411968 - 20 Dec 2024

Cited by 1 | Viewed by 755

Abstract

This study evaluates the performance of biofuels created from triple blends of fossil diesel, sunflower or castor oil (SVOs), and 2-Ethylhexyl Nitrate (EHN), a low-viscosity, high-cetane (LVHC) solvent. EHN reduces the viscosity of SVOs to enable their use in conventional diesel engines without [...] Read more.

This study evaluates the performance of biofuels created from triple blends of fossil diesel, sunflower or castor oil (SVOs), and 2-Ethylhexyl Nitrate (EHN), a low-viscosity, high-cetane (LVHC) solvent. EHN reduces the viscosity of SVOs to enable their use in conventional diesel engines without compromising fuel properties. The results show that the power output from these blends is similar to or greater than that of fossil diesel, with comparable fuel consumption. Furthermore, the blends significantly reduce emissions of carbon monoxide (CO) and soot, though NOx emissions are slightly higher due to the nitrogen content in EHN. However, NOx levels remain within permissible limits. The substitution of fossil diesel could be further enhanced if EHN were produced using green hydrogen and lignocellulosic biomass, making it a renewable and sustainable biofuel component. These findings support the potential of EHN/SVO biofuel blends to replace a significant portion of fossil diesel in conventional diesel engines while maintaining performance and reducing harmful emissions, except for a slight increase in NOx. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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16 pages, 1203 KiB

Open AccessArticle

Characterization of Spent Grain from Irish Whiskey Distilleries for Biorefinery Feedstock Potential to Produce High-Value Chemicals and Biopolymers

by Rasaq S. Abolore, Dileswar Pradhan, Swarna Jaiswal and Amit K. Jaiswal

Appl. Sci. 2024, 14(24), 11577; https://doi.org/10.3390/app142411577 - 11 Dec 2024

Cited by 2 | Viewed by 1285

Abstract

Distiller’s spent grain (DSG) is a byproduct generated in large quantities during the mashing process, particularly in the production of alcoholic beverages such as whiskey. This study aimed to characterize DSG from nine different distilleries as a potential biorefinery feedstock for the synthesis [...] Read more.

Distiller’s spent grain (DSG) is a byproduct generated in large quantities during the mashing process, particularly in the production of alcoholic beverages such as whiskey. This study aimed to characterize DSG from nine different distilleries as a potential biorefinery feedstock for the synthesis of high-value bioproducts. Key components, including protein (12.38–26.32%), cellulose (11.75–32.75%), hemicellulose (6.97–19.47%), lignin (8.44–15.71%), and total phenolics (1.42 to 3.97 mg GAE/g), were analyzed to evaluate their variability and suitability for industrial applications. The results reveal that DSG composition varies significantly across distilleries due to differences in processing techniques, even though the starting grain composition had minimal influence. Statistical analysis highlighted the variability of water- and ethanol-soluble extractives (17.34–31.77%) and their potential impact on product consistency. This compositional variability highlights the importance of understanding DSG’s structural properties to optimize its use as a lignocellulosic biomass feedstock. This study emphasizes the potential for utilizing DSG in the production of nanocellulose, bioplastics, phenolic resins, and other sustainable materials, thereby contributing to the circular economy. By linking compositional insights to specific applications, this work establishes a foundation for tailored utilization of DSG in biopolymer production and chemical synthesis. These findings provide valuable insights for biorefinery operations, addressing both sustainability challenges and the economic potential of industrial byproducts. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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26 pages, 6380 KiB

Open AccessArticle

Cell Disruption and Hydrolysis of Microchloropsis salina Biomass as a Feedstock for Fermentation

by Ayşe Koruyucu, Tillmann Peest, Emil Korzin, Lukas Gröninger, Patricia, Thomas Brück and Dirk Weuster-Botz

Appl. Sci. 2024, 14(21), 9667; https://doi.org/10.3390/app14219667 - 23 Oct 2024

Cited by 1 | Viewed by 1094

Abstract

Microalgae are a promising biomass source because of their capability to fixate CO₂ very efficiently. In this study, the potential of Microchloropsis salina biomass as a feedstock for fermentation was explored, focusing on biomass hydrolysis by employing various mechanical and chemical cell [...] Read more.

Microalgae are a promising biomass source because of their capability to fixate CO₂ very efficiently. In this study, the potential of Microchloropsis salina biomass as a feedstock for fermentation was explored, focusing on biomass hydrolysis by employing various mechanical and chemical cell disruption strategies in combination with enzymatic hydrolysis. Among the mechanical cell disruption methods investigated on a lab scale, namely ultrasonication, bead milling, and high-pressure homogenization, the most effective was bead milling using stainless-steel beads with a diameter of 2 mm. In this way, 87–97% of the cells were disrupted in 40 min using a mixer mill. High-pressure homogenization was also effective, achieving 86% disruption efficiency after four passes on a 30–200 L scale using biomass with 15% (w/w) solids content. Enzymatic hydrolysis of the disrupted cells using a mixture of cellulases and mannanases yielded up to 25% saccharification efficiency after 72 h. Acidic hydrolysis of undisrupted cells followed by enzymatic treatment yielded around 30% saccharification efficiency but was coupled with significant dilution of the resulting hydrolysate. Microalgal biomass hydrolysate produced was determined to have ~8.1 g L⁻¹ sugars and 2.5% (w/w) total carbon, as well as sufficient nitrogen and phosphorus content as a fermentation medium. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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11 pages, 1659 KiB

Open AccessArticle

Life Cycle Assessment of Extraction of Cellulose from Date Palm Biomass Using Natural Deep Eutectic Solvent (NaDES) via Microwave-Assisted Process

by Yousef M. Alanazi, Chun-Yang Yin, Abdullah Al Ragib, Mohanad El-Harbawi and Magaret Sivapragasam

Appl. Sci. 2024, 14(20), 9583; https://doi.org/10.3390/app14209583 - 21 Oct 2024

Viewed by 1864

Abstract

This study investigates the extraction of cellulose from Saudi Arabia-based date palm biomass utilizing a natural deep eutectic solvent (NaDES) integrated with a microwave-assisted process. A comprehensive life cycle assessment (LCA) was conducted in accordance with the ISO 14040 standard, encompassing four key [...] Read more.

This study investigates the extraction of cellulose from Saudi Arabia-based date palm biomass utilizing a natural deep eutectic solvent (NaDES) integrated with a microwave-assisted process. A comprehensive life cycle assessment (LCA) was conducted in accordance with the ISO 14040 standard, encompassing four key stages: goal and scope definition, life cycle inventory analysis (LCI), life cycle impact assessment (LCIA) and interpretation. The analysis was confined to a gate-to-gate boundary in which two impact assessment methods, namely, ReCiPe Midpoint (H) 2016 and ILCD 2011 Midpoint, were used to assess the environmental impacts. The OpenLCA software (version 2.1.1) with the European Life Cycle Database 3.2 (ELCD 3.2) was used in the study. The ReCiPe method identified impact categories such as fossil resource scarcity, terrestrial ecotoxicity, freshwater ecotoxicity, water consumption, human carcinogenic toxicity and marine ecotoxicity. Conversely, the ILCD method identified freshwater ecotoxicity, water resource depletion, mineral, fossil and resource depletion, human toxicity and cancer effects. The results indicate that freshwater ecotoxicity presents the most substantial environmental impact across both assessment methods, surpassing other categories. Fossil resource scarcity, even though originally appearing impactful, demonstrated a relatively lower normalized score compared to freshwater ecotoxicity. Terrestrial ecotoxicity and water consumption were found to be negligible in their impact. Our findings provide important insights into sustainable material science and waste management, affording potential applications for biomass utilization in the Gulf region. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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18 pages, 4975 KiB

Open AccessArticle

Novel Aromatic Estolide Esters from Biobased Resources by a Green Synthetic Approach

by Andra Tămaș, Ioan Bîtcan, Sabina Nițu, Cristina Paul, Ioana Cristina Benea, Gerlinde Iuliana Rusu, Elline Perot, Francisc Peter and Anamaria Todea

Appl. Sci. 2024, 14(17), 7832; https://doi.org/10.3390/app14177832 - 4 Sep 2024

Cited by 1 | Viewed by 1250

Abstract

The use of vegetable oils and their derivatives for polymer synthesis has been a major focus in recent years due to their universal availability, low production costs and biodegradability. In this study, the enzymatic synthesis of oligoesters of ricinoleic acid obtained from castor [...] Read more.

The use of vegetable oils and their derivatives for polymer synthesis has been a major focus in recent years due to their universal availability, low production costs and biodegradability. In this study, the enzymatic synthesis of oligoesters of ricinoleic acid obtained from castor oil combined with three aromatic natural derivatives (cinnamyl alcohol, sinapic acid, and caffeic acid) was investigated. The formation of the reaction products was demonstrated by FT-IR, MALDI-TOF MS and NMR spectroscopy and for the oligo (ricinoleyl)-caffeate the thermal properties and biodegradability in sweet water were analyzed and a rheological characterization was performed. The successful enzymatic synthesis of oligoesters from ricinoleic acid and aromatic monomers using lipases not only highlights the potential of biocatalysis in green chemistry but also contributes to the development of sustainable and biodegradable methods for synthesizing products with potential applications as cosmetic ingredients. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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23 pages, 7249 KiB

Open AccessArticle

Mouthwash Containing Plant-Derived Biosurfactant and Chitosan Hydrochloride: Assessment of Antimicrobial Activity, Antibiofilm Activity, and Genotoxicity

by Izabelle R. Souza, Káren G. O. Bezerra, Camila L. Oliveira, Hugo M. Meira, Thayza C. M. Stamford, Attilio Converti, Leonie A. Sarubbo and Raquel D. Rufino

Appl. Sci. 2024, 14(15), 6711; https://doi.org/10.3390/app14156711 - 1 Aug 2024

Viewed by 1626

Abstract

Plant-derived biosurfactants are widely used due to their emulsifying and surface-active properties and can be applied in various products. The aim of this present study was to develop a mouthwash using chitosan hydrochloride and saponins extracted from the plants Chenopodium quinoa and Glycine [...] Read more.

Plant-derived biosurfactants are widely used due to their emulsifying and surface-active properties and can be applied in various products. The aim of this present study was to develop a mouthwash using chitosan hydrochloride and saponins extracted from the plants Chenopodium quinoa and Glycine max. After extraction of the biosurfactants using the Soxhlet method, they were characterized with the aid of infrared spectroscopy and subjected to determination of critical micelle concentration, which was found to be 4.0 and 3.5 g/L for C. quinoa and G. max, respectively. The stability of the emulsions was investigated in the presence of different oils and at different values of temperature, pH, and salinity, which showed an emulsification index greater than 40% under all conditions analyzed. After obtaining the mouthwash formulation, tests of foaming capacity, pH, and genotoxicity were performed in cells of onion (Allium cepa) roots. No presence of micronuclei was found in the roots exposed to the formulation, which indicates that there was no aggression to the cells. The results of antimicrobial susceptibility tests revealed bacteriostatic/bactericidal activity as well as antibiofilm activity of formulations against the microorganisms tested. In conclusion, the biosurfactants present in extracts from C. quinoa and G. max were found to be stable, non-toxic molecules with antimicrobial activity, with potential to replace toxic emulsifying agents commonly used in commercial products. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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20 pages, 5635 KiB

Open AccessArticle

Hydrothermal Valorization via Liquid Hot Water and Hydrothermal Carbonization of Pea Pod Waste: Characterization of the Biochar and Quantification of Platform Molecules

by Daniel Esteban Galvis-Sandoval, Alejandra Sophia Lozano-Pérez and Carlos Alberto Guerrero-Fajardo

Appl. Sci. 2024, 14(6), 2329; https://doi.org/10.3390/app14062329 - 10 Mar 2024

Cited by 6 | Viewed by 1638

Abstract

Pea pod cultivation spans various regions and climates, with a global production of around 20 million tons. The pea peel wastes, which make up 30–40% of the total weight of the peas, are freely available in large quantities. The biomass used was characterized [...] Read more.

Pea pod cultivation spans various regions and climates, with a global production of around 20 million tons. The pea peel wastes, which make up 30–40% of the total weight of the peas, are freely available in large quantities. The biomass used was characterized via ultimate, proximate, and structural analysis, obtaining 20.2%w of cellulose and 17.4%w of hemicellulose, which, via valorization processes, can be transformed into platform chemicals. Hydrothermal valorization presents itself as a clean form of treatment for these wastes, ranging from 120 to 180 °C (LHW) and from 180 to 260 °C (HTC). The use of LHW can lead to the production of sugars (up to 70%w yield) and levulinic acid (4%w yield), while the use of HTC leads to formic acid (40%w yield) and levulinic acid (4%w yield). The use of LHW for longer periods favors the production of HMF and furfural. The use of homogeneous catalysts (H₂SO₄, CH₃COOH, KOH, and NaHCO₃) was implemented, and their selectivity was described. Solid fractions of LHW and HTC were characterized via FTIR and elemental analysis, and the change in their structure was described as they shifted from biomass to biochar. Optimal conditions for each platform chemical were reported to best utilize the pea pod waste. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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16 pages, 7042 KiB

Open AccessArticle

Comparison of Waste Biomass from Pine, Eucalyptus, and Acacia and the Biochar Elaborated Using Pyrolysis in a Simple Double Chamber Biomass Reactor

by Óscar González-Prieto, Luis Ortiz Torres and Antonio Vazquez Torres

Appl. Sci. 2024, 14(5), 1851; https://doi.org/10.3390/app14051851 - 23 Feb 2024

Cited by 4 | Viewed by 2432

Abstract

Using waste biomass is considered one of the ways to reduce climate change. Arboreal waste biomass from pine, eucalyptus, and particularly invasive plants (Acacias) would make it possible to transform this natural resource, but needs to be adjusted to current and [...] Read more.

Using waste biomass is considered one of the ways to reduce climate change. Arboreal waste biomass from pine, eucalyptus, and particularly invasive plants (Acacias) would make it possible to transform this natural resource, but needs to be adjusted to current and innovative technologies. The production of high fixed carbon biochar with this biomass would improve not only environmental aspects, but also the use of currently not susceptible materials for other types of exploitation. The objective of this study is to develop biochar from three different waste biomass materials and compare their parameters with those of the original biomass. Thermochemical conversion processes were used in a simple double chamber reactor developed for this study. Temperatures between 400 and 500 °C during 280 min were achieved and allowed to transform the initial biomass in a biochar with a high content of fixed carbon. By comparing the original biomass with the final biochar through tests of humidity, density, calorific values, fixed carbon, and cationic and elemental analysis, an increase in the parameters was confirmed. Fixed carbon of 70%, 77%, and 71% with pine, acacia, and eucalyptus biomass have been obtained, respectively, with yields between 30% and 40%. The results are favorable, particularly with acacia invasive plants, and could help in their difficult silviculture management. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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16 pages, 7246 KiB

Open AccessArticle

Synthesis of High-Precision Sub-Micron CaCO₃ Anticancer Drug Carriers from Coral Remains

by Pin-Han Chen, Wei-Sheng Chen, Szu-An Chen and Wei-Chung Chen

Appl. Sci. 2024, 14(4), 1336; https://doi.org/10.3390/app14041336 - 6 Feb 2024

Cited by 1 | Viewed by 1495

Abstract

Calcium carbonate (CaCO₃) particles have attracted increasing attention as a promising material for drug delivery systems. In this study, coral remains were utilized as a raw material for a novel drug carrier. A series of pre-treatment and parameter experiments were conducted [...] Read more.

Calcium carbonate (CaCO₃) particles have attracted increasing attention as a promising material for drug delivery systems. In this study, coral remains were utilized as a raw material for a novel drug carrier. A series of pre-treatment and parameter experiments were conducted to synthesize sub-micron spherical CaCO₃ particles. The CaCO₃ particles exhibited uniform size distribution, with the minimum mean size being only 344 nm. The effects on the CaCO₃ crystal phases and particle sizes were also discussed in this study. Drug loading experiments were also conducted to assess the feasibility of the CaCO₃ drug carrier. We loaded TRITC-Dextran into CaCO₃ particles for the simulation experiments. The loading capacity reached up to 9.6 wt.%, which was as high as common drug carriers such as liposomes. In this study, we aimed not only to tackle the local environmental issues caused by coral remains, but also to synthesize a suitable drug carrier for cancer therapy using the outstanding properties and low cost of CaCO₃. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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17 pages, 4529 KiB

Open AccessArticle

Continuous Adsorption of Acid Wood Dyes onto an Activated Carbon Prepared from Pine Sawdust

by Catarina Helena Pimentel, María Sonia Freire, Diego Gómez-Díaz and Julia González-Álvarez

Appl. Sci. 2024, 14(2), 841; https://doi.org/10.3390/app14020841 - 19 Jan 2024

Cited by 4 | Viewed by 2210

Abstract

In this paper, an activated carbon obtained from Pinus radiata sawdust is applied to remove blue, red, and black wood dyes from aqueous solutions in a fixed-bed column. The flow rate (7.7–30.8 mL min⁻¹), initial dye concentration (25–500 mg L⁻¹ [...] Read more.

In this paper, an activated carbon obtained from Pinus radiata sawdust is applied to remove blue, red, and black wood dyes from aqueous solutions in a fixed-bed column. The flow rate (7.7–30.8 mL min⁻¹), initial dye concentration (25–500 mg L⁻¹), and bed height (2–4 cm) highly influence the breakthrough-curves’ features. The results indicate that the adsorption capacity increased by decreasing the flow rate and increasing the initial dye concentration, except for the black dye, and increasing bed height, except for the red dye. In addition, the breakthrough time changed by modifying the studied variables. The curves became steeper as the flow rate increased and as the bed height decreased. Also, by increasing the inlet dye concentration, the breakthrough time decreased significantly, and sharper breakthrough curves were obtained. The activated carbon with a surface area of 2826 m² g⁻¹ led to high values of the adsorption capacity between 150 and 1300 mg g⁻¹. The Yoon–Nelson and Thomas models were the ones that best described the adsorption data. The activated carbon saturated with black dye could be used in three successive cycles after regeneration with H₂O₂. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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24 pages, 15447 KiB

Open AccessArticle

Characterization of Cellulose Derived from Invasive Alien Species Plant Waste for Application in the Papermaking Industry: Physic-Mechanical, Optical, and Chemical Property Analysis

by Antía Iglesias, Ángeles Cancela, Ana Soler Baena and Ángel Sánchez

Appl. Sci. 2023, 13(20), 11568; https://doi.org/10.3390/app132011568 - 23 Oct 2023

Cited by 3 | Viewed by 1839

Abstract

This study examines the potential of four invasive plant species, both arboreal and herbaceous, within the riparian forest of the Umia River in Galicia, a common ecosystem in northern Spain. These invasive species (Arundo donax, Phytolacca americana, Eucalyptus globulus, [...] Read more.

This study examines the potential of four invasive plant species, both arboreal and herbaceous, within the riparian forest of the Umia River in Galicia, a common ecosystem in northern Spain. These invasive species (Arundo donax, Phytolacca americana, Eucalyptus globulus, and Tradescantia fluminensis) were collected and assessed for their suitability as an alternative source of pulp and paper materials for the paper industry to mitigate the environmental impacts associated with conventional cellulose fiber production from harmful monocultures. Cellulosic material from leaves, bark, and/or stems of each of the selected species was isolated from lignin and hemicelluloses through kraft pulping processes. Resulted fibers and pulps were analyzed visually, morphologically, chemically, and mechanically to evaluate their papermaking properties. To compare these properties with those of commercially available pulp, test sheets were concurrently produced using commercial bleached Eucalyptus cellulose. The findings reveal that the employed fibers exhibit promising characteristics for artistic paper production. Regarding the pulp, two refining times were tested in a PFI machine, and the Schopper–Riegler degree was measured. Paper sheets underwent various tests to determine thickness, basis weight, apparent volume, apparent density, permeability, and chemical composition, as well as microscopic optical and morphological properties. The fibers obtained from the waste derived from the removal of invasive exotic species and biodiversity control present a viable and intriguing alternative for decentralized paper production, yielding noteworthy results for the creative sector. This research highlights the potential of harnessing invasive species for sustainable and innovative paper manufacturing practices. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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Review

Jump to: Research

22 pages, 1005 KiB

Open AccessReview

Pig Slurry Anaerobic Digestion: The Role of Biochar as an Additive Towards Biogas and Digestate Improvement

by Inês Silva, Nuno Lapa, Henrique Ribeiro and Elizabeth Duarte

Appl. Sci. 2025, 15(3), 1037; https://doi.org/10.3390/app15031037 - 21 Jan 2025

Cited by 2 | Viewed by 1356

Abstract

Biowaste from livestock production is increasing globally because of the intensification of livestock farming and inefficient waste management practices. If mismanaged, biowaste can result in environmental problems, including increased greenhouse gas (GHG) emissions. Anaerobic digestion (AD) stands as an effective approach for managing [...] Read more.

Biowaste from livestock production is increasing globally because of the intensification of livestock farming and inefficient waste management practices. If mismanaged, biowaste can result in environmental problems, including increased greenhouse gas (GHG) emissions. Anaerobic digestion (AD) stands as an effective approach for managing livestock biowaste, simultaneously generating biogas for energy recovery and digestate for agronomic application, following the principles of the circular economy. Considered a biowaste-to-energy approach, AD mitigates GHG emissions, facilitates nutrient recovery, and reduces dependence on fossil fuels. Despite its acknowledged benefits and status as a mature technology, further research is required to identify the best route for optimising the process in terms of stability and performance. This review examines new research that explores innovative ways to enhance the mesophilic AD process in continuous-stirred tank reactors, including the use of additives, especially carbon-based ones like biochar. From this perspective, the key challenges are exploring new insights into future research routes to implement AD units at a real scale, and pursuing goals towards a circular economy model. Finally, new opportunities have arisen for farmers to create synergies across agro-industrial sectors, enabling them to minimise their environmental footprint and simultaneously earn additional revenue. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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20 pages, 1988 KiB

Open AccessReview

Feedstock Characterization for Enhanced Heat Recovery from Composting Processes: A Review

by Kareem Osama Fakhri Al-Twal, Giovanni Beggio, Marco Schiavon and Maria Cristina Lavagnolo

Appl. Sci. 2024, 14(23), 11245; https://doi.org/10.3390/app142311245 - 2 Dec 2024

Viewed by 1168

Abstract

Compost Heat Recovery Systems (CHRS) sustainably capture heat from composting waste biomass, helping reduce greenhouse gas emissions and fossil fuel reliance. The choice of feedstock affects the performance of CHRSs as it controls the microbial activities and the amount of heat generated. This [...] Read more.

Compost Heat Recovery Systems (CHRS) sustainably capture heat from composting waste biomass, helping reduce greenhouse gas emissions and fossil fuel reliance. The choice of feedstock affects the performance of CHRSs as it controls the microbial activities and the amount of heat generated. This review evaluates plant-based, animal-derived, and non-agricultural feedstocks to optimize CHRS energy recovery. A systematic review of 244 studies, published from 1996 to 2023 and available on Scopus, Web of Science, and external databases, categorized feedstocks based on properties like carbon-nitrogen ratio (C/N), moisture content, bulk density, and heating value to assess their impact on energy recovery and compost quality. The review followed the PRISMA guidelines, excluding irrelevant documents and those that lacked quantitative data. Animal-based materials, which have high levels of moisture and nutrients, such as nitrogen (14.50–32.20 g/kg TS) and phosphorus (13.0–13.5 g/kg TS), promote rapid growth of microbes and consistent heat production supported by their stable carbon content (353.8–450.0 g/kg TS) and optimal C/N ratios (5.90–28.90). On the other hand, plant-based materials that are rich in volatile solids (327.2–960.0 g/kg TS) and lignin (36.7–290.0 g/kg TS) offer a steady and prolonged release of heat but decompose more slowly. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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32 pages, 2548 KiB

Open AccessReview

From Biogas to Biomethane: An In-Depth Review of Upgrading Technologies That Enhance Sustainability and Reduce Greenhouse Gas Emissions

by Ahinara Francisco López, Telma Lago Rodríguez, Shoeib Faraji Abdolmaleki, Marta Galera Martínez and Pastora M. Bello Bugallo

Appl. Sci. 2024, 14(6), 2342; https://doi.org/10.3390/app14062342 - 11 Mar 2024

Cited by 16 | Viewed by 9957

Abstract

Renewable energies present an opportunity to enhance energy security, reduce dependence on imports, and lower greenhouse gas emissions. Natural gas, viewed as a transitional fuel from coal to renewables, lacks reliable environmental sustainability and does not contribute to EU energy independence. Recently, biomethane [...] Read more.

Renewable energies present an opportunity to enhance energy security, reduce dependence on imports, and lower greenhouse gas emissions. Natural gas, viewed as a transitional fuel from coal to renewables, lacks reliable environmental sustainability and does not contribute to EU energy independence. Recently, biomethane has been gaining attention as an alternative to natural gas. Obtained from purified or “upgraded” biogas, it offers environmental and economic advantages. Several developed technologies, including absorption, adsorption, membrane separation, and cryogenic separation, are commercially available. However, those are energy- and resource-intensive. In this context, this review aims to examine the recent advancements in biogas upgrading, particularly in physical, chemical, and biological pathways. It focuses on CO₂ removal and/or conversion to methane, offering an updated overview for future studies. The technologies are classified based on the separation method (by phase addition, by solid agent, by phase creation, and by biological process), and an analysis of each category is conducted. The discussion covers the economic and environmental characteristics, process complexity, and future research prospects in sustainable technologies. This review highlights the potential of biogas upgrading technologies in contributing to sustainable development, increasing energy security, and achieving greenhouse gas reduction goals that are aligned with EU targets. Full article

(This article belongs to the Special Issue Bioenergy and Bioproducts from Biomass and Waste)

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