Biomass By-products Research Articles

Valorization of Corn Straw for Production of Glucose by Two-Step Depolymerization.

Depolymerization of the cellulose part in lignocellulose to glucose is a significant step for lignocellulose valorization. As one of the main by-products of agricultural biomass in crop-producing filed, valorization of corn straw has attracted considerable attention. In this study, a two-step depolymerizing strategy of high-pressure CO2-H2O pretreatment and oxidation-hydrolysis was applied for selective depolymerization of the cellulose component of corn straw to glucose production. Most part of the hemicellulose component could be removed through high-pressure CO2-H2O pretreatment in the presence of low concentration of acetic acid, and then as high as 32.2 % yield of glucose was achieved in water at 170 °C for 6 h without additional catalyst. The active acid sites generated during the partial oxidation of hydroxymethyl groups to carboxyl groups on glucose units of cellulose was shown to be crucial for the efficient valorization of corn straw for glucose production.

CBD oil by-product (Hemp flakes): Evaluation for nutritional composition, heavy metals and functionality as a food ingredient

BackgroundThe recent interest among consumers in industrial hemp due to health and wellness benefits has led to several products from industrial hemp, including cannabidiol (CBD) oil. CBD oil extraction from hemp buds and flowers generates by-product biomass (hemp flakes), often posing disposal challenges and with little or no applications. We hypothesized that hemp flakes possess residual compounds with nutritional and health value that could be used to improve utilization. MethodsLocally sourced hemp flakes were compared to three commercial hemp protein products. The nutritional composition (proximate analysis), heavy metals (Al, Cu, As, Pb, Co, Cd), and functional composition (phenolic and antioxidant properties–total phenolic compounds (TPC), total flavonoid compounds (TFC), ferric reducing antioxidant potential (FRAP), 1,1–diphenyl-1-picrylhydrazyl (DPPH), Trolox equivalent antioxidant capacity (TEAC)), (CBD, cannabiodiolic acid–CBDA, cannabichromene–CBC, cannabigerol–CBG, and cannabinol–CBN) contents were determined and compared. FindingsHemp flakes had a similar nutritional composition to commercial hemp protein products, with heavy metal levels within FDA allowed limits. The by-product had significantly higher CBDA levels than commercial products. Overall, hemp flakes had comparable nutrient composition and antioxidant capabilities. Based on the protein composition of hemp flakes (31.62 %) versus the highest commercial product (43 %), hemp flakes are an acceptable functional food ingredient.

The Impact of Lignin Biopolymer Sources, Isolation, and Size Reduction from the Macro- to Nanoscale on the Performances of Next-Generation Sunscreen.

In recent years, concerns about the harmful effects of synthetic UV filters on the environment have highlighted the need for natural sun blockers. Lignin, the most abundant aromatic renewable biopolymer on Earth, is a promising candidate for next-generation sunscreen due to its inherent UV absorbance and its green, biodegradable, and biocompatible properties. Lignin's limitations, such as its dark color and poor dispersity, can be overcome by reducing particle size to the nanoscale, enhancing UV protection and formulation. In this study, 100-200 nm lignin nanoparticles (LNPs) were prepared from various biomass by-products (hardwood, softwood, and herbaceous material) using an eco-friendly anti-solvent precipitation method. Pure lignin macroparticles (LMPs) were extracted from beech, spruce, and wheat straw using an ethanol-organosolv treatment and compared with sulfur-rich kraft lignin (KL). Sunscreen lotions made from these LMPs and LNPs at various concentrations demonstrated novel UV-shielding properties based on biomass source and particle size. The results showed that transitioning from the macro- to nanoscale increased the sun protection factor (SPF) by at least 2.5 times, with the best results improving the SPF from 7.5 to 42 for wheat straw LMPs and LNPs at 5 wt%. This study underscores lignin's potential in developing high-quality green sunscreens, aligning with green chemistry principles.

Evaluating Sustainable Practices for Managing Residue Derived from Wheat Straw.

Farm leftovers, particularly crop residues, are a key source of renewable energy in Canada. The nation's robust agricultural industry provides ample biomass, derived from forestry and agriculture resources, for energy generation. Crop residues, such as straws and husks, play a crucial role in this biomass reservoir, contributing to biofuel production and greenhouse gas mitigation efforts. Focusing on supply chains, waste management, and emission reduction, this study evaluates the sustainability of wheat straw, an agricultural biomass by-product. The environmental issues of various approaches to managing agricultural biomass were explored. Following an evaluation of biomass features, conversion methods, and economic and environmental advantages, the results show anaerobic digestion to be the most sustainable approach. Four metrics were examined in relation to social elements, and numerous aspects were considered as inputs in the evaluation of transportation costs. The use of electric trucks versus fuel-based trucks resulted in an 18% reduction in total operating costs and a 58% reduction in consumption costs. This study examined CO2 emissions over four different transportation distances. The data indicate that a significant reduction of 36% in kg CO2 equivalent emissions occurred when the distance was lowered from 100 km to 25 km. These findings offer insights for creating practical plans that should increase the sustainability of agricultural biomass leftovers.

Basic Red 46 adsorption studies onto pyrolyzed by-product biomass

In this study, the objective was to examine the utilization of the pyrolyzed by-products biomass as an adsorbent for extracting the dye Basic Red 46 (BR 46) from a solution. The pyrolyzed by-product containing Pleurotus mutilus biomass was characterized by thermogravimetric analysis (TGA), FTIR and µXRF. Different parameters effects such as, adsorbent dose, solution pH, contact time, temperature and initial dye concentration on the adsorption capacity of the pyrolyzed by-product biomass were examined. The solution was analyzed before and after the adsorption studies. With adsorbent dose of 1 g/L, contact time of 14 min, and solution pH of 7.5, the optimum yield of 88% was achieved. In order to fit the equilibrium data, the Langmuir, Freundlich, Temkin, and Khan isotherm models were used, and in order to fit the kinetics data, the pseudo-first-order, pseudo-second-order, Elovich, and Ritchie models were employed. Statistical analysis such as R2, RMSE,χ2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\chi }^{2}$$\\end{document} and ARE was used to assess which model has the best fit with the experimental data. The results demonstrated that the experimental equilibrium data are well described by the Langmuir model, and the kinetic studies indicated that the adsorption of BR46 followed the Ritchie model. The greatest BR 46 adsorption capacity determined from experimental equilibrium data was around 135 mg/g at pH = 7.5, adsorbent dosage of 1 g/L. Moreover, thermodynamic analysis has demonstrated that the adsorption process was physical, exothermic, and spontaneous in nature. These results indicated that pyrolyzed by-product biomass might be used as a cheap material to extract textile colors out of aqueous effluents.

Pyrolysis kinetics and potential utilization analysis of cereal biomass by-products; an experimental analysis for cleaner energy productions in India

The optimal utilization of biomass relies heavily on the specific material and individual needs. Cereal biomass by-products can potentially be employed in thermochemical processes such as pyrolysis and gasification. To compare biomass sources, ultimate analysis, biochar potential, proximate analysis, thermal gravimetric analysis, price per megajoule generated heat, surface texture, and availability are used. A global survey of biomass wastes and opportunities for heat generation is presented in the current article. Here, nine different cereal-based agricultural waste products (barley, wheat, millet, oats, rice, rye straw, sorghum straw/stalk, and maize cob) are studied. Cereal wastes are compared based on calorific value, water content, volatile matter, ash content and ash chemical composition, bulk density, charring properties, availability, and transportation. According to the estimate, 156 million metric tonnes per year, or 6% of India's total emissions, could be eliminated by rice husk alone. Wheat straws, on the other hand, can cut emissions by 2%. Additionally, processing these nine feedstocks might result in the production of 40 GW of electrical energy, which would increase the installed capacity of India's national electric grid by 9%.

Exploring Novel Applications for Hydrogels Derived from Modified Celluloses.

The valorization of lignocellulosic biomass by-products holds significant economic and ecological potential, considering their global overproduction. This paper introduces the fabrication of a novel wheat-straw-based hydrogel and a new microcellulose-based hydrogel through 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) oxidation. In this study, Fourier transform infrared (FTIR) analysis was employed for the detection of carboxyl groups, neutralization titration was conducted using a conductivity meter, viscosity analysis was performed using a rheometer, and transmittance analysis was carried out using a spectrophotometer. Two novel hydrogels based on TEMPO oxidation have been developed. Among them, the bio-based hydrogel derived from oxidized wheat straw exhibited exceptional printability and injectability. We found that the oxidation degree of microcellulose reached 56-69%, and the oxidation degree of wheat straw reached 56-63%. The cross-linking of 4% oxidized wheat straw and calcium chloride was completed in 400 seconds, and the viscosity exceeded 100,000 Pa·s. In summary, we have successfully created low-cost hydrogels through the modification of wheat straw and microcellulose, transforming lignocellulosic biomass by-products into a sustainable source of polymers. This paper verifies the future applicability of biomass materials in 3D printing.

Biodegradable dust suppressants prepared from biomass-based materials: The role of viscosity and suppressed particles

ABSTRACT In this study, biodegradable dust suppressants were prepared using glycerol and biomass-based oily compounds, including palm oil, biodiesel, and soybean oil. The suppressing ability of the glycerol and the oily compound mixture was evaluated using wind tunnel tests, and factors affecting the suppression of the particles were determined. The replacement of sodium dodecyl sulfate with coco glucoside and lauryl glucoside significantly enhanced the biodegradability of the suppressants (2.02 vs. 9.01 and 8.54 mg/L of BOD5). The glycerol and soybean oil mixture exhibited excellent performance owing to the relatively high viscosity of the suppressants, and the optimal dilution ratio was 1:50 and 1:1000 for sand and granite-weathered soil, respectively. More than 98% of suppression was obtained under the optimal conditions. The effect of the particle properties (particularly permeability) was significant, even though the viscosity of the suppressants was responsible for the suppression of the particles. Our results suggest that the mixture of glycerol and biomass-based oily compounds could be a promising suppressant for reducing the mobility of ultrafine particles in the atmosphere. Implications Since the early 2010s, anthropogenic fugitive dust from industrial activities has become a serious environmental issue due to its serious hazards to the environment and human health in South Korea. So far, several dust suppressants (mostly salts) were made and used for field application. However, due to their toxic effects, it is necessary to develop a new eco-friendly suppressant that can be biodegraded in the soil and that is not hazardous to human health or the environment. Previously we have developed an eco-friendly dust suppressant with low toxicity and high suppression ability using ingredients and by-products of biodiesel production, marine biomass, and commercial vegetable oils (Tsgot and Oh, 2021, J. Air Waste Manag. Assoc. 71:1386–1396). However, due to the low biodegradability of surfactant, the synthesized dust suppressants showed limited biodegradability. As a follow-up to our previous study, we employed readily biodegradable surfactants as additives to enhance the biodegradability of the dust suppressants with the same excellent suppressing ability. To determine the optimal conditions, the synthesis and preparation of the dust suppressants was conducted using biodegradable surfactants, including coco glucoside and lauryl glucoside. The factors affecting the suppressing ability of the suppressants were examined via wind tunnel tests. These factors include the dilution factors, the viscosity of the suppressants, and the type of suppressed particles. Possible suppressing mechanisms were also discussed.

Construction of an electron-transfer channel via Cu-O-Ni to inhibit the overoxidation of Ni for durable methanol oxidation at industrial current density.

The electrocatalytic methanol oxidation reaction (MOR) is a viable approach for realizing high value-added formate transformation from biomass byproducts. However, usually it is restricted by the excess adsorption of intermediates (COad) and overoxidation of catalysts, which results in low product selectivity and inactivation of the active sites. Herein, a novel Cu-O-Ni electron-transfer channel was constructed by loading NiCuO x on nickel foam (NF) to inhibit the overoxidation of Ni and enhance the formate selectivity of the MOR. The optimized NiCuO x -2/NF demonstrated excellent MOR catalytic performance at industrial current density (E 500 = 1.42 V) and high faradaic efficiency of ∼100%, as well as durable formate generation up to 600 h at ∼500 mA cm-2. The directional electron transfer from Cu to Ni and enhanced lattice stability could alleviate the overoxidation of Ni(iii) active sites to guarantee reversible Ni(ii)/Ni(iii) cycles and endow NiCuO x -2/NF with high stability under increased current density, respectively. An established electrolytic cell created by coupling the MOR with the hydrogen evolution reaction could produce H2 with low electric consumption (230 mV lower voltage at 400 mA cm-2) and concurrently generated the high value-added product of formate at the anode.

Customised Microporous Carbon 3D Structures with Good Mechanical Properties and High Nitrogen Content Obtained from Whey Powders

Novel customised carbon monoliths with a high specific surface area were synthesised by carbonisation plus activation of dehydrated whey powders, a biomass byproduct of the dairy industry. The whey powders were casted directly by pouring them into a desired mould. After a pseudo-sintering process promoted by the self-reaction of the whey components (mostly lactose and whey proteins) at moderate temperatures (ca. 250 °C), 3D porous carbons were obtained. The process did not require any binder or external overpressure to prepare the 3D porous carbons. Upon thermal activation with CO2 or chemical activation with H3PO4 and KOH, the shape of the monolithic structure was preserved after the development of a microporous network (SBET up to 2400 m2/g). Both thermal and chemical activation had little effect on the macroporosity of the monoliths. Activation of these 3D carbons had to be performed with care to avoid heterogeneous skin/core activation and/or overactivation. Highly porous monoliths (SBET of 980 m2/g; open porosity of 70%) with outstanding compressive strength (10 MPa) could be obtained by thermal activation (CO2) of whey monoliths at 850 °C for 1.5 h. Additionally, the use of whey as a precursor provided the carbon monolith with a relatively high nitrogen content (ca. 3 wt.%).

Controllable Electron Distribution Reconstruction of Spinel NiCo2O4 Boosting Glycerol Oxidation at Elevated Current Density

AbstractElectrocatalytic glycerol oxidation reaction (GOR) is an effective way to convert biomass byproduct to high value‐added chemicals, which; however, suffers from the low oxidation activity and conversion ratio of the presently available catalysts. Herein, the NiCo2O4/NF bimetallic oxide nanoarray is controllably fabricated by Ni substituting for octahedral Co3+ in Co3O4, which exhibits excellent GOR catalytic activity at elevated current densities (E300 = 1.42 V, E600 = 1.62 V) and overall Faradaic efficiency of 97.5% at 1.42 V (FEformic acid = 89.9% and FEglycolic acid = 7.62%). The high performance is attributed to the structure evolution including the rapid generation of NiIII‐OOH and CoIII‐OOH active species, the optimized intermediates adsorption, and the accelerated electron transfer owing to the Ni introduction, which are evidenced by the operando spectroscopy measurements and density functional theory calculations, respectively. The GOR/hydrogen evolution coupled two‐electrode electrolytic cell voltage is ≈299 mV lower than that of the water splitting at 50 mA cm−2. More importantly, compared to conventional water splitting, this electrolyzer is stable for over 200 h at 1.75 V, reducing energy consumption by 16.9% and obtaining high value‐added products at the anode concurrently.

Application of brewers’ spent grains as an alternative biomass for renewable energy generation in a boiler combustion process

In most industries that generate consumer products the main source of electrical energy comes from burning wood or fossil fuels in boilers. However, the use of these non-renewable fuels poses a huge problem for the current energy matrix and for the environment, which makes new alternatives necessary for a more environmentally friendly scenario. In view of this, our study evaluated the application of brewers’ spent grains (BSG) as an alternative biomass for energy generation in an industrial cogeneration system. For this, different blends of BSG and eucalyptus wood chips were used for steam generation. In addition, the effect of two different dehydration conditions on the drying kinetics of BSG were evaluated. The BSG presented an initial moisture content of 77.68%, 0.52% ash, mean particle size of 0.28 mm, density of 113 kg m–3, and lower calorific value of 17.84 MJ kg–1, making it suitable for energy recovery in a cogeneration system. Outdoor drying under external conditions can be applied to remove the moisture content from BSG, which is a low-cost strategy for further application in the drying process. From the biomass blends, the use of 80% BSG and 20% wood chips promoted better characteristics for application as fuel in a cogeneration system. The use of BSG promoted a reduction in the use of wood chips as fuel and generated a savings of approximately 9 thousand USD annually for the simulated system (80% BSG and 20% wood chips), a reduction of 82% of the cost, when comparing with a system using only wood chips. Therefore, the biomass by-product generated from beer production can be used to produce renewable energy in a cogeneration system, replacing the use of wood chips. The waste-to-energy strategy evaluated in this study can be a promising alternative for a circular economy transition, reducing the waste generated in breweries and promoting the recovery of renewable energy that can be applied in situ, making the entire industrial system become a biorefinery, using its main waste as biofuel to generate clean energy, promoting an energy transition to an increasingly cleaner energetical matrix.

Hydrothermal carbonization of waste wood: Sustainable recycling of biomass by-products and novel performance enhancer for bitumen

Recycling biomass by-products into bitumen is one of the most effective ways to develop sustainable pavements. To cope with the shortage of petroleum resources and improper disposal of discarded biomass, the hydrothermal carbon (HTC) produced by hydrothermal carbonization of waste wood was adopted to reduce the consumption of bitumen and enhance the performance of bitumen, and the mechanical performances and working mechanism of hydrothermal carbon-modified bitumen (HTCMB) were investigated in this study. The results indicate that HTC significantly enhances bitumen's high-temperature and fatigue properties. When the content of HTC is not more than 3%, its effect on the low-temperature cracking resistance of bitumen can be ignored. The addition of HTC absorbs the polar components in bitumen, thus promoting the dispersion of polar components and effectively preventing the mutual aggregation and crystallization of wax components and asphaltenes in bitumen. The excellent mechanical properties of HTCMB can be attributed to the irregular fibrous composition and porous structures of HTC, which play a good role in reinforcing and connecting the bitumen matrix and dramatically enhances the interaction with bitumen. This study proposes a win–win solution to the shortage of petroleum resources in road engineering and the improper disposal of discarded biomass.

Analysis of drying kinetic of brewer´s spent grains: effect of the temperature on the physical properties and the content of bioactive compounds

Background: Brewer´s spent grain (BSG) is a biomass by-product generated in large volumes during industrial beer production. BSG has become a growing environmental problem, as most breweries discard it inappropriately, negatively impacting the environment. Alternatives for the exploitation of this by-product have consisted of elaborating food supplements for farm animals, obtaining biofuels, developing adsorbents, and obtaining substances for the food industry. However, the high moisture content in BSG (approximately 70%), poses a significant challenge in exploring various reuse alternatives. Therefore, the implementation of a pre-drying process becomes essential. Objective: This study aimed to analyze the BSG drying kinetics at different temperatures and the effect of the drying temperature on the physical properties and the content of bioactive compounds. Methods: BSG samples were dried at different temperatures (50, 60, 70, 80, 90, and 105°C) and analyzed for their moisture ratio, water activity, total polyphenol content (TPC), and DPPH (1,1-diphenyl-2-picrylhydrazil) radical scavenging activity. Also, four kinetics models were fitted to the drying data. Results: It was determined that the effective diffusivity was between 5.23x10-10 (m2/s) and 2.49x10-09 (m2/s), and the value of the activation energy was 28.05 kJ/mol. In addition, it was found that the content of phenolic compounds (1.27±0.120 mg gallic acid equivalents /g) and the DPPH radical scavenging activity (0.21±0.015 mg gallic acid equivalents /g) were not significantly affected by the variation in the drying temperatures studied. Conclusions: From an operational point of view, the most suitable temperature for the drying process of BSG was 105°C since it would allow to reach shorter drying times, and the TPC was not affected markedly by the range of temperature studied.

Integration and Optimisation of Palm Oil Sector with Multiple-Industries to Achieve Circular Economy

A typical palm oil sector includes oil palm plantations, palm oil mills, and palm oil refineries. The sector generates a huge amount of biomass by-products, effluent, and refinery wastes. These are usually disposed of at landfills causing inefficient waste management and sustainability issues. As reported in many previoius works, palm-based biomass, palm oil mill effluent (POME) and refinery wastes can be reused or recycled within the palm oil sector. However, there are still large amounts of these which are unprocessed and disposed to landfills. To address this issue, a circular economy approach that integrates the palm oil sector with other industries is needed. This work proposes a mathematical optimisation model to determine the optimal pathway for the circularity of palm-based biomass, POME, and refinery wastes with other sectors. Paper, polymer, and furniture industries are considered to evaluate the potential of a palm-based circular economy. Besides, various biorefineries are also considered, thereby providing multiple pathways for the conversion of palm-based biomass and refinery wastes to value-added products and energy generation. The optimisation is performed under four scenarios – maximise economic potential, minimise net emissions, minimise landfill wastes, and fuzzy multi-objective. The multi-objective results show economic potential of USD 151.36 million, net emissions of −804,946.60 tCO2 and landfill waste reduction by 80.17 %. The results indicate that the polymer industry has better potential to integrate with the palm oil sector. The fuzzy optimisation has allowed to determine trade-off between landfill disposal and resource circularity to maximise the economic value and minimise carbon emissions.

Green utilization of biomass by-product poplar leaf ash: A novel eco-friendly cementitious material for cement mortar replacement

The use of biomass for power generation is increasing. However, solving the solid biomass waste generated during the combustion process is a challenge. In order to reduce costs and the use of forestry waste, the replacement of cement in cement mortars with the same quality of poplar leaf ash was studied. The present study documents the potential of biomass ash obtained from calcined leaf ash as a supplementary cementitious. By thermogravimetric tests, 20 °C, 310 °C, 470 °C, and 650 °C were selected as the calcination temperatures. The effects of biomass ash on uniaxial compressive strength, crack extension, acoustic emission, and the microstructure of specimens at different curing ages of 7 d and 28 d were investigated. The results show that the strength of specimens mixed with 20 wt% poplar leaf ash is about 60% of cement mortar. The porosity of cement mortar specimens with biomass ash is higher than that of cement mortar. The hydration products of C-S-H and AFt are slightly less than cement mortar. To achieve the same flowability, the water-binder ratio is higher when mixed with biomass ash. As a result, the biomass ash specimens have higher porosity and lower strength. The strength of 310 °C and 470 °C is approximately 8.41% and 4.70% lower than that of 650 °C. The optimum calcination temperature for the pozzolanic activity of poplar leaf biomass ash is 650 ℃. This promotes the efficient use of biomass solid waste and the construction industry is green development.

Using wastewater treatment performance, biomass and physiological plant characteristics for selection of a floating macrophyte for phytoremediation of swine wastewater through the integrative Entropy-Fuzzy AHP-TOPSIS method

Phytoremediation success depends on the selection of suitable plant species. To this end, the multiple-attribute decision-making process (MADM) is a useful tool for selecting plants to remediate wastewater. Here, macrophytes were used to treat synthetic swine wastewater (SSW) and the best plant alternative for phytoremediation of SSW was chosen based on the hybrid Entropy-Fuzzy AHP TOPSIS MADM method. The attributes used to feed the MADM method were treatment performance, physiological endpoint changes and biomass by-products. Macrophyte-treated wastewater achieved higher pollutants removal than controls. Lemna, Landoltia, Salvinia, Azolla and Control units had removals of 81 %, 79 %, 68 %, 81 %, 25 % for tCOD; 66 %, 71 %, 65 %, 68 %, 8 % for P-PO43−; 51 %, 63 %, 40 %, 66 %, 14 % for N-NO3−; 36 %, 36 %; 26 %; 42 %; 7 % for N-NH4+; 51 %, 40 %, 52 %, 63 %, 3 % for Cu; and 25 %, 18 %, 26 %, 42 %, 14 % for Zn, respectively. Furthermore, Azolla and Lemna removed more SSW toxicity and presented the lowest phyto-stress index (0.09) and highest lipids production (14 % dw) during treatment. Azolla proved to be the best option for phytoremediation of swine wastewater, since it had the highest rank as determined by the proposed method. Acute toxic units of the treated effluent (0.38) and phyto-stress index (0.49) had the greatest weight in choosing the best plant while the production of biomass volatile solids and removals of P-PO43− and tCOD were the least influential. This study provided a reliable approach to select the best plant from available macrophytes capable of improving physicochemical and ecotoxicological quality of wastewater and offer value-added plant biomass products.

Techno-Economic Assessment of On-Site Production of Biomethane, Bioenergy, and Fertilizer from Small-Scale Anaerobic Digestion of Jabuticaba By-Product

Bioenergy recovery from biomass by-products is a promising approach for the circular bioeconomy transition. However, the management of agri-food by-products in stand-alone treatment facilities is a challenge for the low-capacity food processing industry. In this study, the techno-economic assessment of a small-scale anaerobic digestion process was evaluated for the management of jabuticaba by-product and the production of biomethane, electricity, heat, and fertilizer. The process was simulated for a treatment capacity of 782.2 m3 y−1 jabuticaba peel, considering the experimental methane production of 42.31 L CH4 kg−1 TVS. The results of the scaled-up simulated process demonstrated the production of biomethane (13,960.17 m3 y−1), electricity (61.76 MWh y−1), heat (197.62 GJ y−1), and fertilizer (211.47 t y−1). Economic analysis revealed that the process for biomethane recovery from biogas is not profitable, with a net margin of −19.58% and an internal rate of return of −1.77%. However, biogas application in a heat and power unit can improve project feasibility, with a net margin of 33.03%, an internal rate of return of 13.14%, and a payback of 5.03 years. In conclusion, the application of small-scale anaerobic digestion can prevent the wrongful open-air disposal of jabuticaba by-products, with the generation of renewable energy and biofertilizer supporting the green economy toward the transition to a circular economy.

Convective drying of mango stone for use as biomass

Mango stone is an interesting biomass by-product with a considerable net calorific value. Mango production has significantly risen in the last few years, meaning that mango waste has increased as well. However, mango stone has a moisture content of about 60% (wet basis) and it is very important to dry the samples for using them in electrical and thermal energy production. In this paper, the main parameters involved in the mass transfer during drying are determined. Drying was carried out in a convective dryer through a set of experiments based on five drying air temperatures (100 °C, 125 °C, 150 °C, 175 °C and 200 °C) and three air velocities (1 m/s, 2 m/s and 3 m/s). Drying times ranged between 2 and 23 h. The drying rate was calculated from the Gaussian model whose values ranged from 1.5·10−6 to 6.3·10−4 s−1. Effective diffusivity was obtained as an overall parameter in the mass diffusion for each test. These values were found between 0.71·10−9 and 13.6·10−9 m2/s. The activation energy was calculated from the Arrhenius law for each test, made at different air velocities. These values were 36.7, 32.2 and 32.1 kJ/mol for 1, 2 and 3 m/s, respectively. This study provides information for future works on design, optimization and numerical simulation models in convective dryers for standard mango stone pieces according to industrial drying conditions.

A Circular Approach for the Valorization of Tomato By-Product in Biodegradable Injected Materials for Horticulture Sector.

This study focuses on the use of tomato (Solanum lycopersicum L.) by-product biomass from industrial plants as reinforcement for designing a range of new degradable and biobased thermoplastic materials. As a novel technique, this fully circular approach enables a promising up-cycling of tomato wastes. After an in-depth morphological study of the degree of reinforcement through SEM and dynamic analysis, mechanical characterization was carried out. Our mechanical results demonstrate that this circular approach is of interest for composite applications. Despite their moderate aspect ratio values (between 1.5 and 2), the tomato by-product-reinforced materials can mechanically compete with existing formulations; PBS-Tomato fiber, for example, exhibits mechanical performance very close to that of PP-flax, especially regarding strength (+11%) and elongation at break (+6%). According to the matrix and particle morphology, a large range of products-biobased and/or degradable, depending on the targeted application-can be designed from tomato cultivation by-products.