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1.
Talanta ; 236: 122838, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34635228

RESUMEN

Medium-resolution (MR-NMR) and time-domain NMR relaxometry (TD-NMR) using benchtop and low-field NMR instruments are powerful tools to tackle fuel adulteration issues. In this work, for the first time, we investigate the possibility of enhancing the low-field NMR capability on fuel analysis using data fusion of MR and TD-NMR. We used the ComDim (Common Dimensions Analysis) multi-block analysis to join the data, which allowed exploration, classification, and quantification of common adulterations of diesel fuel by vegetable oils, biodiesel, and diesel of different sources as well as the sulfur content. After data exploration using ComDim, classification (applying linear discriminant analysis, LDA), and regression (applying multiple linear regression, MLR), models were built using ComDim scores as input variables on the LDA and MLR analyses. This approach enabled 100% of accuracy in classifying diesel fuel source (refinery), sulfur content (S10 or S500), vegetable oil, and biodiesel source. Moreover, in the quantification step, all MLR models showed a root mean square error of prediction (RMSEP) and the residual prediction deviation (RPD) values comparable to the literature for determining diesel, vegetable oil, and biodiesel contents.


Asunto(s)
Biocombustibles , Gasolina , Biocombustibles/análisis , Gasolina/análisis , Espectroscopía de Resonancia Magnética , Monitoreo Fisiológico , Aceites Vegetales
2.
J Hazard Mater ; 421: 126732, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34332475

RESUMEN

Bio-heavy oil (BHO) is a renewable fuel, but its efficient use is problematic because its combustion may emit hazardous air pollutants (e.g., polycyclic aromatic hydrocarbon (PAH) compounds, NOx, and SOx). Herein, catalytic fast pyrolysis over HZSM-5 zeolite was applied to upgrading BHO to drop-in fuel-range hydrocarbons with reduced contents of hazardous species such as PAH compounds and N- and S-containing species (NOx and SOx precursors). The effects of HZSM-5 desilication and linear low-density polyethylene (LLDPE) addition to the feedstock on hydrocarbon production were explored. The apparent activation energy for the thermal decomposition of BHO was up to 37.5% lowered by desilicated HZSM-5 (DeHZSM-5) compared with HZSM-5. Co-pyrolyzing LLDPE with BHO increased the content of drop-in fuel-range hydrocarbons and decreased the content of PAH compounds. The DeHZSM-5 was effective in producing drop-in fuel-range hydrocarbons from a mixture of BHO and LLDPE and suppressing the formation of N- and S-containing species and PAH compounds. The DeHZSM-5 enhanced the hydrocarbon production by up to 58.5% because of its enhanced porosity and high acid site density compared to its parent HZSM-5. This study experimentally validated that BHO can be upgraded to less hazardous fuel via catalytic fast co-pyrolysis with LLDPE over DeHZSM-5.


Asunto(s)
Contaminación del Aire , Biocombustibles , Biomasa , Catálisis , Sustancias Peligrosas , Calor
3.
Waste Manag ; 135: 448-456, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34624743

RESUMEN

In the present study, a combined technology for energetic brewery spent grain (BSG) use in co-digestion with sewage sludge (SS) was presented. A holistic approach that includes the impact of co-substrates and their carriers on the anaerobic digestion (AD) process, and the energetic aspects, was involved. Prior to AD, BSG was pretreated involving the hydrodynamic cavitation (HC); two different carriers were applied: MPW (municipal pre-settled wastewater) and mature landfill leachate (MLL). An orifice plate with a conical concentric hole of 3/10 mm (inlet/outlet diameter) was applied as cavitation device. The initial pressure was 7 bar and the number of recirculation passes through the cavitation zone was 30. The AD experiments were performed in semi-flow reactors, under mesophilic conditions at HRT of 20 and 21 d. In both co-digestion series, the constant co-substrate dose of 6% v/v was adopted. In the presence of cavitated BSG and MPW, a significant increase in biogas/methane production was provided as compared to SS mono-digestion, with the related improvement in kinetic constant by 3.5%. The average biogas yield was 0.48 ± 0.03 m3 kg-1 VS added, while in the control run 0.41 ± 0.03 m3 kg-1 VS added. Using cavitated BSG and MLL, such a beneficial effect was not observed. In both co-digestion series, slightly lower VS removal (as for the control) and stable process performance occurred. Moreover, the improved energy balance was provided. Due to the technological aspects, only co-digestion of cavitated BSG and MPW with SS is recommended for implementation into a full-scale.


Asunto(s)
Biocombustibles , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Digestión , Metano , Aguas Residuales
4.
J Environ Manage ; 300: 113827, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34649320

RESUMEN

This study developed and evaluated a high-purity butyrate producing bioprocess from food waste by combining dry fermentation (DF) with a microbial fuel cell (MFC). Acclimatization of a DF reactor with an enrichment culture resulted in high food waste degradation (VS removed, %) and butyrate production. A high VS degradation of 81%, butyrate concentration of up to 24 gCODbutyrate/L and butyrate yields of 497 gCODbutyrate/kg VSadded was obtained in the DF reactor. As a result, butyrate comprised 83% of all short chain fatty acids (SCFA) in the DF broth. Acetate (10%) and propionate (7%) comprised the rest of the SCFA. The butyrate composition was further purified by feeding the DF broth to a multi-electrode MFC enriched with anode respiring bacteria (ARB) such as Geobacter sp. (>55%). The ARB in the MFC removed acetate and propionate while purified butyrate was recovered in the MFC effluent. Butyrate purity in the MFC effluent reached as high as 99% at hydraulic retention time of 72 h. Along with butyrate purification, the MFC produced electric power in a range of 0.1-0.6 Wh/gCODbutyraterecovered (or 0.01-7.85 kWh/ton of food waste), demonstrating that MFCs can be an energy-positive butyrate purification bioprocess.


Asunto(s)
Fuentes de Energía Bioeléctrica , Eliminación de Residuos , Antagonistas de Receptores de Angiotensina , Inhibidores de la Enzima Convertidora de Angiotensina , Butiratos , Electricidad , Electrodos , Fermentación , Alimentos
5.
J Environ Manage ; 300: 113831, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34649321

RESUMEN

Wastewater and activated sludge present a major challenge worldwide. Wastewater generated from large and small-scale industries, laundries, human residential areas and other sources is emerging as a main problem in sanitation and maintenance of smart/green cities. During the last decade, different technologies and processes have been developed to recycle and purify the wastewater. Currently, identification and fundamental consideration of development of more advanced microbial-based technologies that enable wastewater treatment and simultaneous resource recovery to produce bioenergy, biofuels and other value-added compounds (organic acids, fatty acids, bioplastics, bio-pesticides, bio-surfactants and bio-flocculants etc.) became an emerging topic. In the last several decades, significant development of bioprocesses and techniques for the extraction and recovery of mentioned valuable molecules and compounds from wastewater, waste biomass or sludge has been made. This review presents different microbial-based process routes related to resource recovery and wastewater application for the production of value-added products and bioenergy. Current process limitations and insights for future research to promote more efficient and sustainable routes for this under-utilized and continually growing waste stream are also discussed.


Asunto(s)
Aguas Residuales , Purificación del Agua , Biocombustibles , Biomasa , Humanos , Aguas del Alcantarillado
6.
Sci Total Environ ; 792: 148446, 2021 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-34465036

RESUMEN

A double-chamber microbial fuel cell (MFC) with Ru/Fe-modified-biocathode was constructed for simultaneous mineralization of 2-anilinophenylacetate (APA) and denitrification. The factors on performance of simultaneous APA degradation and denitrification were explored. The contributions of ROS to APA degradation were evaluated by EPR and quenching experiments. The microbial community of Ru/Fe-modified-biocathode was determined by high-throughput sequencing. Results showed that low resistance accelerated APA degradation by Ru/Fe-modified-biocathode, while higher initial APA concentration inhibited microbial activity of the biocathode. The optimum ammonia concentration was 50 mg L-1, while too high or too low ammonia concentration did not favor APA degradation. The APA degradation efficiency of Ru/Fe-modified-biocathode-MFC was higher than that of other modified-cathode-MFCs. The APA degradation process confirmed to the pseudo-first-order kinetic model, and APA degradation kinetic constant, the maximum removal efficiency of TOC, ammonia and TN were 2.15d-1, 59.70%, 99.20% and 44.56% respectively, signifying a simultaneous APA mineralization and denitrification performance of Ru/Fe-modified-biocathode-MFC. The coulombic efficiency decreased with APA concentration increase. OH was the primary radical in APA degradation progress. Eight kinds of intermediates were measured, and two APA degradation pathways were proposed, among which APA hydroxylation was the main pathway. The microbial community of Ru/Fe-modified-biocathode was dominated with Nitrosomonas at genus level, and enriched with various APA-degraders, nitrifiers, and denitrifiers such as Pseudomonas, Nitrospira, Nitrobacter, Paracoccus, Thermomonas, Dechloromonas, and Clostridium_Sutra_stricto_1. COG analysis showed the redox reaction of Ru/Fe might affect signal transduction and environment adaptation, while FAPROTAX analysis suggested that Ru/Fe-modified-biocathode exhibited higher nitrification activity than that of carbon-felt-biocathode. The synergistic mechanism of simultaneous APA mineralization and denitrification was mainly redox reaction of Ru/Fe and supplemented by aerobic biodegradation.


Asunto(s)
Fuentes de Energía Bioeléctrica , Reactores Biológicos , Desnitrificación , Electrodos , Nitrificación , Nitrógeno/análisis , Aguas Residuales
7.
Water Res ; 204: 117554, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34500179

RESUMEN

To reduce greenhouse gas emissions and promote resource recovery, many wastewater treatment operators are retrofitting existing plants to implement new technologies for energy, nutrient and carbon recovery. In literature, there is a lack of studies that can unfold the potential environmental and economic impacts of the transition that wastewater utilities are undertaking to transform their treatment plants to water resource recovery facilities (WRRFs). When existing, literature studies are mostly based on simulations rather than real plant data and pilot-scale results. This study combines life cycle assessment and economic evaluations to quantify the environmental and economic impacts of retrofitting an existing wastewater treatment plant (WWTP), which already implements energy recovery, into a full-scale WRRF with a series of novel technologies, the majority of which are already implemented full-scale or tested through pilot-scales. We evaluate five technology alternatives against the current performance of the WWTP: real-time N2O control, biological biogas upgrading coupled with power-to-hydrogen, phosphorus recovery, pre-filtration carbon harvest and enhanced nitrogen removal. Our results show that real-time N2O control, biological biogas upgrading and pre-filtration lead to a decrease in climate change and fossil resource depletion impacts. The implementation of the real-time measurement and control of N2O achieved the highest reduction in direct CO2-eq emissions (-35%), with no significant impacts in other environmental categories. Biological biogas upgrading contributed to counterbalancing direct and indirect climate change impacts by substituting natural gas consumption and production. Pre-filtration increased climate change reduction by 13%, while it increased impacts in other categories. Enhanced sidestream nitrogen removal increased climate change impacts by 12%, but decreased marine eutrophication impacts by 14%. The reserve base resource depletion impacts, however, were the highest in the plant configurations implementing biological biogas upgrading coupled with power-to-hydrogen. Environmental improvements generated economic costs for all alternatives except for real-time N2O control. The results expose possible environmental and economic trade-offs and hotspots of the journey that large wastewater treatment plants will undertake in transitioning into resource recovery facilities in the coming years.


Asunto(s)
Eliminación de Residuos Líquidos , Purificación del Agua , Biocombustibles , Aguas Residuales , Recursos Hídricos
8.
Science ; 373(6561): 1308-1309, 2021 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-34529473

RESUMEN

[Figure: see text].


Asunto(s)
Fuentes de Energía Bioeléctrica , Electrodos , Plata
9.
Environ Sci Pollut Res Int ; 28(38): 52832-52843, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34476693

RESUMEN

Rising human population has increased the utilization of available resources for food, clothes, medicine, and living space, thus menacing natural environment and mounting the gap between available resources, and the skills to meet human desires is necessary. Humans are satisfying their desires by depleting available natural resources. Therefore, multifunctional plants can contribute towards the livelihoods of people, to execute their life requirements without degrading natural resources. Thus, research on multipurpose industrial crops should be of high interest among scientists. Hemp, or industrial hemp, is gaining research interest because of its fastest growth and utilization in commercial products including textile, paper, medicine, food, animal feed, paint, biofuel, biodegradable plastic, and construction material. High biomass production and ability to grow under versatile conditions make hemp, a good candidate species for remediation of polluted soils also. Present review highlights the morphology, adaptability, nutritional constituents, textile use, and medicinal significance of industrial hemp. Moreover, its usage in environmental conservation, building material, and biofuel production has also been discussed.


Asunto(s)
Cannabis , Alérgenos , Animales , Biocombustibles , Biomasa , Humanos , Industrias
10.
J Hazard Mater ; 416: 125845, 2021 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-34492798

RESUMEN

Aflatoxins (AFs) are the extremely hazardous metabolites (carcinogens) that are sporadically observed in crops, and these toxic chemicals are indeed lethal to the health of living organisms including human beings. Thus, AF contaminated food waste needs to be disposed as an environmentally benign way, not releasing it into the environment. This study offered a sustainable disposal and valorization platform for AF contaminated food. Peanut was used as a model food waste, because AF is readily appeared in the peanut during its harvesting, cultivation, storage, transportation process. As the valorization platform, non-catalytic transesterification of AF contaminated peanut was employed to convert it to biodiesel (BD). From the process, lipid in AF contaminated peanut is converted into BD (95.2 wt% yield) at 365°C for 1 min. Since the boiling points of BD and AF are significantly different, this process could also resolve the separation problem of AF (180 °C) from BD (≥ 330 °C) during the transesterification reaction. As a comparison study, alkali-catalyzed reaction was done. The alkali-catalyzed one required a pretreatment process to extract peanut oil for transesterification. The highest yield was 67.8 wt% yield after 6 h of reaction at 65 °C.


Asunto(s)
Aflatoxinas , Eliminación de Residuos , Arachis , Biocombustibles , Esterificación , Alimentos , Humanos
11.
J Hazard Mater ; 416: 125864, 2021 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-34492812

RESUMEN

Reactive red 2 (RR2) is a highly recalcitrant and toxic azo dye that can cause the collapse of biological treatment system. Although MFC can decolorize RR2 effectively, its performance is still inevitably affected by toxicity. Anthraquinone can enhance MFCs' performance through mediating electron transfer. In this study, an anthraquinone-rich natural plants (B.rheum (Rheum offcinale Baill)) was extracted and then added to MFCs. The optimal dosage was selected and the enhanced effects were investigated. The results showed that adding 5%(V/V) extract resulted in the optimal performance elevation of MFC. When 5% extract was added together with RR2, 15.63% and 1.33-fold improvement in RR2 decolorization efficiency and rate were achieved compared with the control group. Meanwhile, higher power density (2.75 W/m3), coulombic efficiency (6.45%), and lower internal resistance (233.69 Ω) were also observed when 5% B.rheum extract and RR2 were added. B.rheum extract in MFCs enhanced microbial activity and enriched the dye-degrading microorganisms, such as Enterobacter, Raoultella, Comamonas and Shinella. B.rheum extract acts as "antidote" in alleviating the biotoxicity of RR2 was firstly illustrated in this study. The results provided a new strategy for using plant-source electron mediators to simultaneously improve biological detoxification, bioelectricity generation and dye decolorization in bioelectrochemical system.


Asunto(s)
Compuestos Azo , Fuentes de Energía Bioeléctrica , Compuestos Azo/toxicidad , Colorantes/toxicidad , Electricidad , Electrodos , Transporte de Electrón , Electrones
12.
J Hazard Mater ; 416: 125865, 2021 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-34492813

RESUMEN

Anaerobic biological treatment technologies are one of the major hotspots of antibiotic resistance genes (ARGs). Previous studies have applied the electrochemical process to improve biogas production, however, it was challenged that high voltages might promote membrane permeability and reactive oxygen species overproduction to promote ARGs proliferation. Herein, the biogas production and ARGs proliferation in an anaerobic electrochemical membrane bioreactor (AnEMBR) were investigated at the gradient voltages of 0-0.9 V. Results show the reactor performances (average CH4 production and current generation) were distinctly improved with the increase of applied voltage, and reached the optimum at 0.9 V. However, long-term application (>30 day) of 0.9 V deteriorated the reactor performances. Meanwhile, the relative abundances of most target ARGs in the supernatant and effluent of AnEMBR at 0.9 V increased by 0.68-1.55 and 0.42-1.26 logs compared to those before applying voltage, respectively. After disconnecting the circuit, these ARGs abundances all decreased to the original level. Significant correlations between intlI and ARGs (e.g., tetA, tetQ, sulI, and sulII) were observed, indicating horizontal gene transfer may contribute to the increased ARGs. Moreover, the shift of microbial communities caused by the applied voltage enriched potential ARGs-hosts (e.g., Tolumonas), contributing to the proliferation of ARGs.


Asunto(s)
Antibacterianos , Biocombustibles , Anaerobiosis , Antibacterianos/farmacología , Reactores Biológicos , Proliferación Celular , Farmacorresistencia Microbiana/genética , Genes Bacterianos
13.
J Environ Manage ; 300: 113684, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34509817

RESUMEN

Biomethanation potential of lignin rich residue (LRR) obtained from lignocellulosic ethanol fermentation was evaluated after subjecting to microbe assisted pretreatment using selectively enriched lignin depolymerizing consortia (LDC). The efficiency of LDC in lignin depolymerization was established using alkali and dealkali lignins (AL and DL) along with LRR as feedstocks. Microbial growth on media having lignin as sole carbon source, activity of lignin depolymerizing enzymes, viz., lignin peroxidase and laccase, ability of culture to decolorize the lignin mimicking dyes like methylene blue and ramezol brilliant blue, were considered to confirm the efficiency of enriched mixed culture. Microbial treatment using LDC showed significant positive impact on lignin breakdown irrespective of the substrate (LRR, 46.33%; AL, 31.37%; DL, 34.20%). The hydrolysate of LRR obtained from microbial pretreatment showed higher biogas yield (424 ml/g VS) owing to the efficiency of lignin depolymerization and availability of readily available biodegradable components in residual lignin from previous processing. Depolymerization of commercial lignins also produced a good amount of biogas (302-324 ml/g VS) after pretreatment with LDC. Overall, an additional energy conversion efficiency of about 11.75 kJ/g VS was obtained by valorizing the residual lignin through integrating biomethanation technology to ethanol fermentation. Outcome of this study indicated the feasibility of using lignin rich residue generated from the second generation cellulosic bioethanol plants as a potential feedstock to meet the current gaseous fuel demands. This integration also helps in closing the biomass based biorefinery loop and also promotes the circular economy.


Asunto(s)
Biocombustibles , Lignina , Biomasa , Fermentación , Gases , Lignina/metabolismo
14.
J Environ Manage ; 300: 113772, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34560470

RESUMEN

Plant design implies the best choice among a set of feedstock-to-product process pathways. Multiple sustainability performance indicators can blur the decision, and existing sustainability assessment methods usually focus only on environmental life-cycle performance and corporate metrics or solely on the gate-to-gate process. It is relevant to incorporate integrated system analysis to address sustainability comprehensively. To this end, the Sustainable Process Systems Engineering (S-PSE) method was previously introduced to select the most sustainable feedstock-process-product configuration via four-dimensional indicators (environment, efficiency, health-&-safety, and economic), and then pinpoint the sustainability hotspots of the best design to unveil possible improvements. This work expands S-PSE by adding new features: (i) cradle-to-gate environmental assessment; (ii) composition of flowsheets; (iii) new indicators; (iv) statistical screening of indicators; and (v) 2030 Agenda compliance. A biorefinery case-study demonstrates S-PSE: to select the best pathway from soybean-oil, palm-oil, and microalgae-oil to biodiesel, green-diesel, and propylene-glycol. Firstly, statistical screening reduces the indicator set by 62%. Results evince all routes from microalgae-oil as economically unfeasible due to oil cost, despite superior environmental performance. S-PSE evinces palm-oil-to-biodiesel as the most sustainable due to lower cradle-to-gate emissions and manufacturing cost, with sustainability hotspots associated to hazardous methanol input and energy-intensive distillations. 2030 Agenda analysis also outlines palm-oil-to-biodiesel as best for 5 out of 10 Sustainable Development Goals linked to the reduced indicator set.


Asunto(s)
Biocombustibles , Microalgas , Alquenos , Glicoles
15.
J Environ Manage ; 300: 113788, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34562817

RESUMEN

Profitability studies are needed to establish the potential pathways required for viable biomethane production in the Brandenburg region of Germany. This work study the profitability of a potential biomethane production plant in the eastern German region of Brandenburg, through a specific practical scenario with data collected from a regional biogas plant located in Alteno (Schradenbiogas GmbH & Co. KG). Several parameters with potential economic influence such as distance of the production point to the grid, waste utilization percentage, and investment, were analyzed. The results illustrate a negative overall net present value with the scenario of no governmental investment, even when considering trading the CO2 obtained throughout the process. Subsidies needed to reach profitability varied with distance from 13.5 €/MWh to 19.3 €/MWh. For a fixed distance of 15 kms, the importance of percentage of waste utilization was examined. Only 100% of waste utilization and 75% of waste utilization would reach profitability under a reasonable subsidies scheme (16.3 and 18.8 €/MWh respectively). Concerning the importance of investment, a subsidized investment of at least 70% is demanded for positive net present values. Besides, the sensitivity analysis remarks the energy consumption of the biogas upgrading stage, the electricity price, and the energy consumption of biogas production as major parameters to be tackled for the successful implementation of biogas upgrading plants. The results here obtained invite to ponder about potential strategies to further improve the economic viability of this kind of renewable projects. In this line, using the CO2 separated to produce added-value chemicals can be an interesting alternative.


Asunto(s)
Alimentos , Eliminación de Residuos , Biocombustibles , Electricidad , Alemania , Metano
16.
J Environ Manage ; 300: 113746, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34562822

RESUMEN

Greenhouse gas emissions from power plants that use fossil fuels cause a serious impact to the environment, for this reason the use of renewable energy technologies is an important alternative as a way of combatting climate change. The production of power via biomass is considered as a carbon neutral energy resource, but it is well known that the non-fossil CO2 emitted from this type of processes can also be captured. In order to do so, in this work it is proposed a match between a Biogas combined cycle power plant and postcombustion carbon capture process, to capture the CO2 produced by the biogas combustion, and also it considered a match with an organic Rankine cycle that uses the wasted energy of the combustion gases. Additionally, it is considered that the captured carbon is used to produce some value-added chemicals and fuels. Environmental and energetic evaluations were carried out for the coupling of those technologies. The implementation of the carbon capture plant, results on a diminution of the 87% of the emission of the combined cycle power plant. The life cycle analysis results show that the study case of Syngas production via dry reforming of methane, presents the lower global warming potential (0.088 CO2-eq kg/kg) and it was also found that the global warming potential has a reduction with the help of the mass integration between the different alternatives of CO2 utilization. Finally, it was found an annual reduction of 0.055 CO2-eq t for the system with mass integration compared with the cases without mass integration.


Asunto(s)
Biocombustibles , Dióxido de Carbono , Carbono , Dióxido de Carbono/análisis , Efecto Invernadero , Centrales Eléctricas
17.
Environ Sci Technol ; 55(19): 12809-12817, 2021 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-34523924

RESUMEN

Airborne carbonyl compounds such as formaldehyde, acrolein, and methyl ethyl ketone have long been chemicals-of-concern in the environment due to their reactivity and their potential for negative health effects. Standard methods for determining carbonyls in air, which focus on a set of 15 or fewer compounds, involve derivatization to form nonvolatile hydrazones, which can readily be analyzed via liquid chromatography (LC) with ultraviolet detectors. Here, we apply a new LC-high-resolution mass spectrometry (HRMS) method to natural gas and a variety of upgraded biofuels to better assess their total carbonyl profile using the inherent selectivity of the standard sampling methodology and the selectivity and sensitivity of HRMS. The standard method accounted for only 64% of the total carbonyl content in natural gas and between 26 and 45% of the total carbonyl content in biogas sources, with the balance detected by the new LC/HRMS method. An additional 540 compounds with molecular formulas consistent with carbonyl compounds were detected compared to only 14 target compounds using the standard method. These results demonstrate that the established method dramatically under-reports both the total carbonyl load and the diversity of carbonyl species in natural gas and biogas samples.


Asunto(s)
Biocombustibles , Gas Natural , Acroleína , Formaldehído , Espectrometría de Masas
18.
Waste Manag ; 135: 47-59, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34474306

RESUMEN

The increase in anaerobic digestion systems has profoundly affected the waste management of territories, particularly for agricultural systems. Changes in cultural practices and imports of organic waste modify the carbon (C) and nitrogen (N) fluxes on territories where anaerobic digestion is implemented. Successful anaerobic digestion can increase the economic and ecological efficiency of the waste management system. Conversely, poor anaerobic digestion leads to low economic and environmental efficiency due to greenhouse gas emissions and nutrient loss. Modeling the impact of anaerobic digestion on the systems integrating anaerobic digestion can improve the efficiency of these practices. The aim of this study was to develop, analyze, and evaluate a simple mass balance tool able to predict carbon and nitrogen fluxes in anaerobic digestion systems. The tool is composed of an exhaustive substrate database used by three models: (i) an anaerobic digestion model that predicts C and N contents in biogas and digestate; (ii) a phase separation model that predicts C and N content in liquid and solid phase digestates; and (iii) a storage model that predicts C and N content in raw, liquid phase, and solid phase digestates, as well as C and N emissions during storage. Sensitivity analyses were performed on the tool to determine critical inputs. Sensitivity analysis showed that outputs were highly sensitive to their respective inputs and to total inputs of solids. Performance evaluation showed that the tool can provide good quality predictions with R2 correlations between observation and prediction varying from 0.72 to 0.99 with the best predictions obtained for raw digestate.


Asunto(s)
Carbono , Nitrógeno , Agricultura , Anaerobiosis , Biocombustibles , Nitrógeno/análisis
19.
Biosens Bioelectron ; 194: 113614, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34500225

RESUMEN

The performance of bioelectrochemical systems (BESs) is significantly influenced by metabolic interactions within a particular microbial community. Although some studies show that interspecific metabolic cooperation benefits BESs performance, the effect of interspecific substrate competition on BESs performance has not yet been discussed. Herein, the impact of interspecific competition is investigated by monitoring the extracellular electron transfer of exoelectrogenic Shewanella oneidensis MR-1 and non-exoelectrogenic Citrobacter freundii An1 alone and simultaneously. The bacterial consortia generate the highest current of 38.4 µA cm-2, 6 times of that produced by the single strain S. oneidensis MR-1. Though S. oneidensis MR-1 loses out to C. freundii An1 in solution, the competition enhances the metabolic activity of S. oneidensis MR-1 on electrode, which facilitates the biofilm formation and therefore helps S. oneidensis MR-1 to gain an competitive advantage over C. freundii An1. Increased metabolic activity triggers more electrons generation and flavin secretion of S. oneidensis MR-1 which contributes to its excellent exoelectrogenic capacity. The proteomics analysis confirms that the expression of proteins related to lactate metabolism, biofilm formation, and outer membrane c-type cytochromes are significantly upregulated in S. oneidensis MR-1 from bacterial consortia.


Asunto(s)
Fuentes de Energía Bioeléctrica , Técnicas Biosensibles , Citrobacter freundii/genética , Ecología , Shewanella
20.
Waste Manag ; 135: 243-255, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34543813

RESUMEN

The valorization of waste frying oil (WFO) to biodiesel has been carried out via solid base catalyzed transesterification reaction. A novel potassium tin oxide (KSO) catalyst was synthesized via polymer precursor auto combustion method. The catalyst showed the best physicochemical properties when it was calcined at 800 °C. Using KSO 800 catalyst, the highest FAME conversion (99.5%) of WFO found at moderated reaction condition within very short time (35 min); moreover, no leaching of K-species was observed in reusability test upto 5th cycle. Kinetics proved that the above catalytic reaction followed pseudo-first-order kinetics and the rate of the reaction was doubled with increasing 10 °C reaction temperature. The reaction activation energy, enthalpy of activation, entropy of activation, and Gibb's free energy of activation of the reaction were found to be 66.52 kJ/mol, 62.95 kJ/mol, -74.07 J/mol/K and 88 kJ/mol respectively. Evaluation of the green parameters revealed that KSO 800 catalyzed transesterification process approached a cleaner route with excellent efficacy in terms of turnover frequency and yield. KSO 800 helped to produce high quality biodiesel from WFO adopting faster and greener reaction pathway. Thus, KSO 800 was considered as a potential and green catalyst for transforming waste oil into biofuel.


Asunto(s)
Biocombustibles , Administración de Residuos , Catálisis , Esterificación , Aceites Vegetales , Potasio , Compuestos de Estaño
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