Biodiesel Production by Methanolysis of Rapeseed Oil-Influence of SiO2/Al2O3 Ratio in BEA Zeolite Structure on Physicochemical and Catalytic Properties of Zeolite Systems with Alkaline Earth Oxides (MgO, CaO, SrO).

Alkaline earth metal oxide (MgO, CaO, SrO) catalysts supported on BEA zeolite were prepared by a wet impregnation method and tested in the transesterification reaction of rapeseed oil with methanol towards the formation of biodiesel (FAMEs-fatty acid methyl esters). To assess the influence of the SiO2/Al2O3 ratio on the catalytic activity in the tested reaction, a BEA zeolite carrier material with different Si/Al ratios was used. The prepared catalysts were tested in the transesterification reaction at temperatures of 180 °C and 220 °C using a molar ratio of methanol/oil reagents of 9:1. The transesterification process was carried out for 2 h with the catalyst mass of 0.5 g. The oil conversion value and efficiency towards FAME formation were determined using the HPLC technique. The physicochemical properties of the catalysts were determined using the following research techniques: CO2-TPD, XRD, BET, FTIR, and SEM-EDS. The results of the catalytic activity showed that higher activity in the tested process was confirmed for the catalysts supported on the BEA zeolite characterized by the highest silica/alumina ratio for the reaction carried out at a temperature of 220 °C. The most active zeolite catalyst was the 10% CaO/BEA system (Si/Al = 300), which showed the highest triglyceride (TG) conversion of 90.5% and the second highest FAME yield of 94.6% in the transesterification reaction carried out at 220 °C. The high activity of this system is associated with its alkalinity, high value of the specific surface area, the size of the active phase crystallites, and its characteristic sorption properties in relation to methanol.

Influence of salinity, nitrogen and phosphorus concentrations on the physiological and biochemical characteristics of two Chlorophyceae isolated from Fez freshwater, Morocco.

Microalgae are widely exploited for numerous biotechnology applications, including biofuels. In this context, Chlamydomonas debaryana and Chlorococcum sp. were isolated from Fez freshwater (Morocco), and their growth and lipid and carbohydrate production were assessed at different concentrations of NaCl, NaNO3, and K2HPO4. The results indicate a small positive variation in growth parameters linked to nutrient enrichment, with no considerable variation in carbohydrate and lipid levels in both algae. Moreover, a negative variation was recorded at increased salinity and nutrient limitation, accompanied by lipid and carbohydrate accumulation. Chlorococcum sp. showed better adaptation to salt stress below 200 mM NaCl. Furthermore, its growth and biomass productivity were strongly reduced by nitrogen depletion, and its lipid production reached 47.64% DW at 3.52 mM NaNO3. As for Chlamydomonas debaryana, a substantial reduction in growth was induced by nutrient depletion, a maximal carbohydrate level was produced at less than 8.82 mM NaNO3 (40.59% DW). The effect of phosphorus was less significant. However, a concentration of 0.115 mM K2HPO4 increased lipid and carbohydrate content without compromising biomass productivity. The results suggest that growing the two Chlorophyceae under these conditions seems interesting for biofuel production, but the loss of biomass requires a more efficient strategy to maximize lipid and carbohydrate accumulation without loss of productivity.

Stimulatory effects of smoke solution and biogas digestate slurry application on photosynthesis, growth, and methylation profiling of solanum tuberosum.

Biostimulants are obtained from various sources like plants, animals, microorganisms, and industrial by-products as well as waste material. Their utilization in agriculture practices is being increased that is giving positive results. The purpose of the current study was to use plant-derived smoke (SMK) solution and biogas digestate (BGD) slurry as biostimulant to elucidate their impact on potato (Solanum tuberosum) performance. The experiment was conducted in lab as well as field conditions, and SMK and BGD solutions were prepared in varying concentrations such as SMK 1:500, SMK 1:250, BGD 50:50, and BGD 75:25. Foliar applications were performed thrice during experiments and data were collected related to photosynthesis, growth, pigments, and genome-wide methylation profiling. Net photosynthesis rate (A) and water use efficiency (WUE) were found higher in SMK- and BGD-treated lab and field grown plants. Among pigments, BGD-treated plants depicted higher levels of Chl a and Chl b while SMK-treated plants showed higher carotenoid levels. Alongside, enhancement in growth-related parameters like leaf number and dry weight was also observed in both lab- and field-treated plants. Furthermore, DNA methylation profile of SMK- and BGD-treated plants depicted variation compared to control. DNA methylation events increased in all the treatments compared to control except for SMK 1:500. These results indicate that smoke and slurry both act as efficient biostimulants which result in better performance of plants. Biostimulants also affected the genome-wide DNA methylation profile that resultantly might have changed the plant gene expression profiling and played its role in plant responsiveness to these biostimulants. However, there is need to elucidate a possible synergistic effect of SMK and BGD on plant growth along with gene expression profiling.

Combining anaerobic digestion slurry and different biochars to develop a biochar-based slow-release NPK fertilizer.

In this research, we developed a biochar-based fertilizer using biogas slurry and biochar derived from lignocellulosic agro-residues. Biogas slurry was obtained through the anaerobic digestion of the organic fraction of municipal solid waste (fresh vegetable biomass and/or prepared food), while biochars were derived from residues from quinoa, maize, rice, and sugarcane. The biochar-based fertilizers were prepared using an impregnation process, where the biogas slurry was mixed with each of the raw biochars. Subsequently, we characterized the N, P and K concentrations of the obtained biochar-based fertilizers. Additionally, we analyzed their surface properties using SEM/EDS and FTIR and conducted a slow-release test on these biochar-based fertilizers to assess their capability to gradually release nutrients. Lastly, a bioassay using cucumber plants was conducted to determine the N, P, and K bioavailability. Our findings revealed a significant correlation (r > 0.67) between the atomic O/C ratio, H/C ratio, cation exchange capacity, surface area, and the base cations concentration with N, P, and/or K adsorption on biochar. These properties, in turn, were linked to the capability of the biochar-based fertilizer to release nutrients in a controlled manner. The biochar-based fertilizer derived from corn residues showed <15 % release of N, P and K at 24 h. Utilization of these biochar-based fertilizers had a positive impact on the mineral nutrition of cucumber plants, resulting in an average increase of 61 % in N, 32 % in P, and 19 % in K concentrations. Our results underscore the potential of biochar-based fertilizers in controlled nutrient release and enhanced plant nutrition. Integration of biochar and biogas slurry offers a promising and sustainable approach for NPK recovery and fertilizer production in agriculture. This study presents an innovative and sustainable approach combining the use of biochar for NPK recovery from biogas slurry and its use as a biochar-based fertilizer in agriculture.

Evaluation of biomass sources on the production of biofuels from lignocellulosic waste over zeolite catalysts.

Catalytic fast pyrolysis (CFP) is a promising method to convert biomass waste into sustainable bio-oils. However, the relationship gap between biomass characteristics and bio-oil quality has hindered the development of CFP technology. This study investigated the pyrolysis and CFP of ten biomass sources over zeolites, and showed that biomass sources and zeolites played important roles in bio-oil production. For noncatalytic trials, the bio-oil yield was positively related to holocellulose (R2 = 0.75) and volatiles content (R2 = 0.62) but negatively to ash content (R2 = -0.65). The bio-oil quality was dramatically improved after catalyst addition. For CFP over ZSM-5, hydrocarbons selectivity of bio-oils was increased by 1.6∼79.3 times, which was closely related to H/C ratio (R2 = 0.79). For ZSM-5@SBA-15 trials, the dependency of hydrocarbons selectivity on biomass characteristics was less clear than that in ZSM-5 counterparts, although undesirable PAHs were inhibited for most biomass sources. This study demonstrated the influence mechanism of biomass characteristics on bio-oil compositions.

Measuring risk of renewable diesel production processes using a multi-criteria decision strategy.

This study proposes measuring the risk of five alternative renewable diesel production technologies using a multi-criteria decision matrix strategy. Evaluated criteria include environmental, economic, technological, social, and process safety risks. The subjective Analytical Hierarchy Process (AHP) with stakeholder input provides criteria and sub-criteria weightings and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) ranks alternatives. Alternative renewable diesel options are Green Diesel from first, second, and third-generation feedstocks, Fischer-Tropsch Diesel from second-generation biomass, and the transesterification of vegetable oils (VO) to make biodiesel. This study is a response to an earlier work measuring the sustainability of the same renewable technologies. While the previous work indicated Fischer-Tropsch Diesel as the most sustainable, this current work indicated the process as the "most risky," suggesting that risk is a significant driver of decision making over sustainability, and newly developed decision tools should address both perspectives.

Excess Enthalpies Analysis of Biofuel Components: Sunflower Oil-Alcohols Systems.

This study addresses the pressing issues of energy production and consumption, in line with global sustainable development goals. Focusing on the potential of alcohols as "green" alternatives to traditional fossil fuels, especially in biofuel applications, we investigate the thermochemical properties of three alcohols (n-propanol, n-butanol, n-pentanol) blended with sunflower oil. The calorimetric analysis allows for the experimental determination of excess enthalpies in pseudo-binary mixtures at 303.15 K, revealing similarities in the trends of the curves (dependence on concentrations) but with different values for the excess enthalpies for each mixture. Despite the structural differences of the alcohols studied, the molar excess enthalpy values exhibit uniformity, suggesting consistent mixing behavior. The peak values of excess enthalpies for systems with sunflower oil and n-propanol, n-butanol and n-pentanol are, respectively, 3255.2 J/mole, 3297.4 J/mole and 3150.1 J/mole. Both the NRTL and Redlich-Kister equations show satisfactory agreement with the obtained values.

Production of biodiesel from waste fish fat through ultrasound-assisted transesterification using petro-diesel as cosolvent and optimization of process parameters using response surface methodology.

Biodiesel is a highly promising and viable alternative to fossil-based diesel that also addresses the urgent need for effective waste management. It can be synthesized by the chemical modification of triglycerides sourced from vegetable origin, animal fat, or algal oil. The transesterification reaction is the preferred method of producing biodiesel. However, the non-miscibility of alcohol and oil layer causes excessive utilization of alcohol, catalyst, and a substantial reacting time and temperature. In the current investigation, transesterification of waste fish oil was performed with petro-diesel as cosolvent, under the influence of ultrasound energy. The combination of both techniques is a unique and efficient way to minimize the mass transfer limitations considerably and hence reduces the parameters of the reaction. It is also a sincere effort to comply with the principles of green chemistry. The optimum reaction conditions were obtained using response surface methodology (RSM) that were as follows: molar ratio of methanol to oil 9.09:1, catalyst concentration of 0.97 wt%, cosolvent concentration of 29.1 wt%, temperature 60.1℃, and a reacting time 30 min. Under these listed conditions, 98.1% biodiesel was achievable, which was in close agreement with the expected result. In addition, the cosolvent removal step from the crude biodiesel was also eliminated as it could be employed as a blended fuel in CI engines.

Exogenous GABA supplementation to facilitate Cr (III) tolerance and lipid biosynthesis in Chlorella sorokiniana.

Microalgae possess the prospective to be efficiently involved in bioremediation and biodiesel generation. However, conditions of stress often restrict their growth and diminish different metabolic processes. The current study evaluates the potential of GABA to improve the growth of the microalga Chlorella sorokiniana under Cr (III) stress through the exogenous administration of GABA. The research also investigates the concurrent impact of GABA and Cr (III) stress on various metabolic and biochemical pathways of the microalgae. In addition to the control, cultures treated with Cr (III), GABA, and both Cr (III) and GABA treated were assessed for accurately analysing the influence of GABA. The outcomes illustrated that GABA significantly promoted growth of the microalgae, resulting in higher biomass productivity (19.14 mg/L/day), lipid productivity (3.445 mg/L/day) and lipid content (18%) when compared with the cultures under Cr (III) treatment only. GABA also enhanced Chl a content (5.992 µg/ml) and percentage of protein (23.75%). FAMEs analysis by GC-MS and total lipid profile revealed that GABA treatment can boost the production of SFA and lower the level of PUFA, a distribution ideal for improving biodiesel quality. ICP-MS analysis revealed that GABA supplementation could extend Cr (III) mitigation level up to 97.7%, suggesting a potential strategy for bioremediation. This novel study demonstrates the merits of incorporating GABA in C. sorokiniana cultures under Cr (III) stress, in terms of its potential in bioremediation and biodiesel production without disrupting the pathways of photosynthesis and protein production.

Impact of macronutrients and salinity stress on biomass and biochemical constituents in Monoraphidium braunii to enhance biodiesel production.

Microalgal lipids are precursors to the production of biodiesel, as well as a source of valuable dietary components in the biotechnological industries. So, this study aimed to assess the effects of nutritional (nitrogen, and phosphorus) starvations and salinity stress (NaCl) on the biomass, lipid content, fatty acids profile, and predicted biodiesel properties of green microalga Monoraphidium braunii. The results showed that biomass, biomass productivity, and photosynthetic pigment contents (Chl. a, b, and carotenoids) of M. braunii were markedly decreased by nitrogen and phosphorus depletion and recorded the maximum values in cultures treated with full of N and P concentrations (control, 100%). These parameters were considerably increased at the low salinity level (up to 150 mM NaCl), while an increasing salinity level (up to 250 mM NaCl) reduces the biomass, its productivity, and pigment contents. Nutritional limitations and salt stress (NaCl) resulted in significantly enhanced accumulation of lipid and productivity of M. braunii, which represented more than twofold of the control. Furthermore, these conditions have enhanced the profile of fatty acid and biodiesel quality-related parameters. The current study exposed strategies to improve M. braunii lipid productivity for biodiesel production on a small scale in vitro in terms of fuel quality under low nutrients and salinity stress.

Evaluation of fuel properties for possible biodiesel output based on the fatty acid composition of oleaginous plants and microalgae.

In the past decade, there has been a significant rise in sustainable biomass based biofuel production to address energy needs while mitigating environmental impacts. Traditionally, bioethanol was used for biofuel production, but concerns over food security and environmental preservation have led to growing interest in alternative sources such as neutral lipids from vegetable oil and microalgae for biodiesel production. This research paper evaluates the potential of various oleaginous plants and microalgae as feedstocks for biodiesel production, with a focus on their fatty acid composition and its impact on biodiesel properties. The study examines the fatty acid profiles of 43 different plant and microalgae species and employs various equations to estimate key physical properties of biodiesel. Additionally, the communication compares these properties to International Biodiesel Standards (EN 14214 and ASTM D6751-08) to assess the suitability of the derived biodiesel for commercial use. It is impossible to describe a single composition that is optimal in terms of all essential fuel properties due to the opposing effects of some structural features of the Fatty Acid Methyl Esters (FAME). However, biodiesel should contain relatively low concentrations of both long chain saturated and polyunsaturated FAME to ensure adequate efficiency in terms of low temperature operability and oxidative stability. The results reveal significant variations in properties amongst different feedstocks, highlighting the importance of feedstock selection in biodiesel production. The study also establishes correlations between various fuel properties, providing valuable insights in to optimizing biodiesel production processes, which will be of great use to researchers, engineers, and stakeholders involved in biodiesel production.

Sequencing analysis and efficient biodiesel production by lipase from Pseudomonas aeruginosa.

BACKGROUND: Recently, lipase processing for biodiesel production has shown a global increase as it is considered a potential alternative clean-fuel source. The current study's objective is to investigate of lipolytic activity of lipase produced from different strains of Pseudomonas aeruginosa (P. aeruginosa) in biodiesel production using edible plant oils. The goal is to develop an efficient and cost-effective method for producing inexpensive and environmentally friendly biodiesel. METHODS AND RESULTS: Four P. aeruginosa isolates were obtained from different environmental sources (soil), phenotypically identified, and it was confirmed by the PCR detection of the 16SrRNA gene. The isolated P. aeruginosa strains were screened for lipase production, and the recovered lipase was purified. Besides, the lipase (lip) gene was detected by PCR, and the purified PCR products were sequenced and analyzed. The production of biofuel was conducted using gas chromatography among tested oils. It was found that castor oil was the best one that enhances lipase production in-vitro.

Predicting co-liquefaction bio-oil of sewage sludge and algal biomass via machine learning with experimental optimization: Focus on yield, nitrogen content, and energy recovery rate.

Machine learning (ML), a powerful artificial intelligence tool, can effectively assist and guide the production of bio-oil from hydrothermal liquefaction (HTL) of wet biomass. However, for hydrothermal co-liquefaction (co-HTL), there is a considerable lack of application of experimentally verified ML. In this work, two representative wet biomasses, sewage sludge and algal biomass, were selected for co-HTL. The Gradient Boosting Regression (GBR) and Random Forest (RF) algorithms were employed for regression and feature analyses on yield (Yield_oil, %), nitrogen content (N_oil, %), and energy recovery rate (ER_oil, %) of bio-oil. The single-task results revealed that temperature (T, °C) was the most significant factor. Yield_oil and ER_oil reached their maximum values around 350 °C, while that of N_oil was around 280 °C. The multi-task results indicated that the GBR-ML model of the dataset#4 (n_estimators = 40, and max_depth = 7,) owed the highest average test R2 (0.84), which was suitable for developing a prediction application. Subsequently, through experimental validation with actual biomass, the best GBR multi-task ML model (T ≥ 300 °C, Yield_oil error < 11.75 %, N_oil error < 2.40 %, and ER_oil error < 9.97 %) based on the dataset#6 was obtained for HTL/co-HTL. With these steps, we developed an application for predicting the multi-object of bio-oil, which is scarcely reported in co-hydrothermal liquefaction studies.

Aviation fuel based on wastewater-grown microalgae: Challenges and opportunities of hydrothermal liquefaction and hydrotreatment.

The current technical issues related to the conversion of algal biomass into aviation biofuel through hydrothermal liquefaction (HTL) and the upgrading of bio-oil through hydrotreatment have been reviewed and consolidated. HTL is a promising route for converting microalgae into sustainable aviation fuel (SAF). However, HTL must be followed by the hydrotreatment of bio-oil to ensure that its composition and properties are compatible with SAF standards. The fact that microalgae offer the possibility of recovering wastewater treatment resources not only makes them more attractive but also serves as an incentive for wastewater treatment, especially in countries where this service has not been universalized. The combination of SAF and wastewater treatment aligns with the Sustainable Development Goals of the United Nations, representing an advantageous opportunity for both aviation and sanitation. In this context, the utilization of HTL by-products in the concept of a biorefinery is essential for the sustainability of aviation biofuel production through this route. Another important aspect is the recovery and reuse of catalysts, which are generally heterogeneous, allowing for recycling. Additionally, discussions have focused on biomass pretreatment methods, the use of solvents and catalysts in HTL and hydrotreatment reactions, and the operational parameters of both processes. All these issues present opportunities to enhance the quantity and quality of bio-oil and aviation biofuel.

An integrated approach for wastewater treatment and algae cultivation: Nutrient removal analysis, biodiesel extraction, and energy and environmental metrics enhancement.

Human urine is rich in nitrogen and phosphorus, and the presence of these elements in wastewater significantly disrupts the biogeochemical cycle. Meanwhile, green algal biomass cultivation is unfeasible without these nutrients. Hence, the present study integrates wastewater treatment and algae cultivation to extract biodiesel and improve its performance through fuel modification. Chlorella vulgaris algae was cultivated in different dilution ratios of water and urine, and the nutrient removal rate was analyzed. Chlorella vulgaris algae biodiesel (CAB) was derived through Bligh and Dyer's method followed by transesterification, and its functional and elemental groups were analyzed. The various volume concentrations of CAB were blended with regular diesel fuel (RDF), and 10% water was added to a 30% CAB blended RDF to evaluate the combustion performance and environmental impacts. The results of the experiments demonstrated that the algae cultivation effectively removed the wastewater nutrients. The functional and elemental groups of CAB are identical to those of RDF. The engine characteristics of test fuels report that the CAB-blend RDF fuel mixtures generate low carbon footprints, whereas negative impacts have been drawn for performance metrics and oxides of nitrogen emissions. The water-emulsified fuel outweighed the unfavorable effects and promoted more efficient and cleaner combustion.

In situ hydrodeoxygenation of heavy bio-oil using a Ce/Fe-based oxygen carrier in methanol-zero valent aluminum media.

Resource recovery from solid organic wastes, such as degradable plastics, and upgrading raw bio-oil are important ways for reducing carbon and pollution emissions. Hydrodeoxygenation (HDO) is a common thermochemical treatment to upgrade crude bio-oil. In this study, in order to realize in situ HDO during the hydropyrolysis of heavy bio-oil and degradable plastics, a reduced Fe/Ce oxygen carrier (OC) was used to catalytically remove oxygen from organics under the methanol-zero valent aluminum (ZV Al) media, where the hydrogen was produced during pyrolysis instead of a direct hydrogen supply. The results showed that the reduced OC captured the oxygen from the pyrolysis products of heavy bio-oil and degradable plastic, representing the multi-selectivity of reduced OC to phenols, ketones, etc. The ZV Al system promoted the production and utilization of hydrogen, as evidenced by the increased hydrogen content in gas phase and hydrocarbon content in liquid phase. The hydrocarbon component distribution in the liquid phase increased clearly when hydropyrolysis with degradable plastics addtion, but the excess degradable plastics addition caused increasing of the liquid product viscosity, and decreasing of the liquid products yield for the higher ash content in degradable plastic, and a higher ZV Al amount was required to maintain the hydropyrolysis. Molecular dynamics simulations verified the synergistic effect of degradable plastics and bio-oil by the pyrolysis behavior in different systems and temperatures, and the pyrolysis pathways were proposed. This non-autocatalytic system realized the resource recovery and heavy bio-oil upgrading using an Fe/Ce OC.

Catalytic flash pyrolysis of Scenedesmus sp. post-extraction residue using low-cost HZSM-5 catalyst with the perspective to produce renewable aromatic hydrocarbons.

Recovering renewable chemicals from de-fatted microalgal residue derived from lipid extraction within the algal-derived biofuel sector is crucial, given the rising significance of microalgal-derived biodiesel as a potential substitute for petroleum-based liquid fuels. As a circular economy strategy, effective valorization of de-fatted biomass significantly improves the energetic and economic facets of establishing a sustainable algal-derived biofuel industry. In this scenario, this study investigates flash catalytic pyrolysis as a sustainable pathway for valorizing Scenedesmus sp. post-extraction residue (SPR), potentially yielding a bio-oil enriched with upgraded characteristics, especially renewable aromatic hydrocarbons. In the scope of this study, volatile products from catalytic and non-catalytic flash pyrolysis were characterized using a micro-furnace type temperature programmable pyrolyzer coupled with gas chromatographic separation and mass spectrometry detection (Py-GC/MS). Flash pyrolysis of SPR resulted in volatile products with elevated oxygen and nitrogen compounds with concentrations of 46.4% and 26.4%, respectively. In contrast, flash pyrolysis of lyophilized microalgal biomass resulted in lower concentrations of these compounds, with 40.9% oxygen and 17.3% nitrogen. Upgrading volatile pyrolysis products from SPR led to volatile products comprised of only hydrocarbons, while completely removing oxygen and nitrogen-containing compounds. This was achieved by utilizing a low-cost HZSM-5 catalyst within a catalytic bed at 500 °C. Catalytic experiments also indicate the potential conversion of SPR into a bio-oil rich in monocyclic aromatic hydrocarbons, primarily BETX, with toluene comprising over one-third of its composition, thus presenting a sustainable pathway for producing an aromatic hydrocarbon-rich bio-oil derived from SPR. Another significant finding was that 97.8% of the hydrocarbon fraction fell within the gasoline range (C5-C12), and 35.5% fell within the jet fuel range (C8-C16). Thus, flash catalytic pyrolysis of SPR exhibits significant promise for application in drop-in biofuel production, including green gasoline and bio-jet fuel, aligning with the principles of the circular economy, green chemistry, and bio-refinery.

Sustainable valorization of macroalgae residual biomass, optimization of pyrolysis parameters and life cycle assessment.

The major challenges for the current climate change issue are an increase in global energy demand, a limited supply of fossil fuels, and increasing carbon footprints from fossil fuels, which have necessitated the exploration of sustainable alternatives to fossil fuels. Biorefineries offer a promising path to sustainable fuel production, converting biomass into biofuels using diverse technologies. Aquatic biomass, such as macroalgae in this context, represents an abundant and renewable biomass resource that can be cultivated from water bodies without competing with traditional agricultural land. Despite this, the potential of macroalgae for biofuel production remains largely untapped, with very limited studies addressing their viability and efficiency. This study investigates the efficient conversion of unexplored macroalgae biomass through a biorefinery process that involves lipid extraction to produce biodiesel, along with the production of biochar and bio-oil from the pyrolysis of residual biomass. To improve the effectiveness and overall performance of the pyrolysis system, Response Surface Methodology (RSM) was utilized through a Box-Behnken design to systematically investigate how alterations in temperature, reaction time, and catalyst concentration influence the production of bio-oil and biochar to maximize their yields. The results showed the highest bio-oil yield achieved to be 36 %, while the highest biochar yield reached 45 %. The integration of Life Cycle Assessment (LCA) in the study helps to assess carbon emission and environmental burdens and identify potential areas for optimization, such as resource efficiency, waste management, and energy utilization. The LCA results contribute to the identification of potential environmental hotspots and guide the development of strategies to optimize the overall sustainability of the biofuel production process. The LCA results indicate that the solvent (chloroform) used in transesterification contributes significantly to greenhouse gas emissions and climate change impacts. Therefore, it is crucial to explore alternative, safe solvents that can mitigate the environmental impacts of transesterification.

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

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.

Fractional condensation of bio-oil vapors from pyrolysis of various sawdust wastes in a bench-scale bubbling fluidized bed reactor.

The use of lignocellulosic waste as an energy source for substituting fossil fuels has attracted lots of attention, and pyrolysis has been established as an effective technology for this purpose. However, the utilization of bio-oil derived from non-catalytic pyrolysis faces certain constraints, making it impractical for direct application in advanced sectors. This study has focused on overcoming these challenges by employing fractional condensation of pyrolytic vapors at distinct temperatures. The potential of five types of sawdust for producing high-quality bio-oil through pyrolysis conducted with a bench-scale bubbling fluidized bed reactor was investigated for the first time. The highest yield of bio-oil (61.94 wt%) was produced using sample 3 (damaged timber). Remarkably, phenolic compounds were majorly gathered in the 1st and 2nd condensers at temperatures of 200 °C and 150 °C, respectively, attributing to their higher boiling points. Whereas, carboxylic acid, ketones, and furans were mainly collected in the 3rd (-5 °C) and 4th (-20 °C) condensers, having high water content in the range of 35.33%-65.09%. The separation of acidic nature compounds such as acetic acid in the 3rd and 4th was evidenced by its low pH in the range of 4-5, while the pH of liquid collected in the 1st and 2nd condensers exhibited higher pH (6-7). The well-separated bio-oil derived from biomass pyrolysis facilitates its wide usage in various applications, proposing a unique approach toward carbon neutrality. In particular, achieving efficient separation of phenolic compounds in bio-oil is important, as these compounds can undergo further upgrading to generate hydrocarbons and diesel fuel.