Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 25
Filtrar
1.
J Hazard Mater ; 472: 134445, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38701727

RESUMO

The prevalence of microplastic (MP) contamination has become a significant environmental concern due to its pervasive nature and persistent effects. While sediments are considered major repositories for MPs, information on their spatial distribution within these matrices is insufficient. This research examined both the horizontal and vertical presence of MPs in the sediments surrounding Lake Paldang in South Korea, alongside a comprehensive evaluation of the physicochemical characteristics of the samples obtained. The total content of MPs varied from 2.15 to 122.2 particles g-1. The average contents of MPs on surface sediments were 40.47, 34.14, 5.01, and 8.19 particles g-1 in north mainstream (NM), south mainstream (SM), tributary (TB), and Tributary catchment (TC) based on Sonae Island, Gyeongan stream, respectively. The most abundant MP types were polyethylene (PE), polytetrafluoroethylene (PTFE), and polypropylene (PP), accounting for more than 70% of the total MPs. The most abundant sizes of MPs were within 45-100 µm. At all sediment depths, polymers were distributed in the order PE, PP, and polyester in NM, SM, and TC, respectively, whereas PTFE mainly occurred in the surface layer. MPs distribution also exhibited seasonal variation as larger inflows and flow rates varied with season.

2.
ACS Appl Mater Interfaces ; 15(25): 30692-30706, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37326512

RESUMO

An efficient interfacial heating system composed of a light-absorbing material and a hydrophilic porous support is developed through eco-friendly and energy-effective fabrication processes. Lignin nanoparticles (NPs) and cellulose nanofibers (CNFs) are harnessed as biorenewable light absorbers and hydrophilic supports, respectively. Lignin NPs are prepared using a solvent exchange process of the fractionated lignin with organic solvents to improve its π-π stacking and light-absorbing property for efficient photothermal conversion. Then, the lignin NPs are mixed with CNFs and lyophilized to obtain a light-absorbing porous hydrogel (LAPH), and the resulting LAPHs are covalently cross-linked and hybridized with Au NPs through a seed-mediated growth to further enhance their mechanical stability, hydrophilicity, and photothermal conversion properties. The resulting LAPHs exhibit an outstanding and prolonged performance as a solar steam generator such as high salt and pH tolerance, evaporation rate (3.17 kg m-2 h-1), and solar steam generation efficiency (83.4%) under 1 sun irradiation.

3.
ACS Omega ; 7(47): 43092-43101, 2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36467915

RESUMO

Laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS) analysis is harnessed to investigate the chemical structure and photochemical properties of two distinct graphene oxide (GO) derivatives simultaneously. The GO derivatives are synthesized with modified Brodie's method (BGO) and Hummers' method (HGO) and characterized by LDI-TOF-MS as well as conventional tools. A series of LDI-TOF-MS analyses reveal that BGO provides higher laser energy absorption, photochemical stability, and photothermal conversion property than HGO based on their fragmentation patterns and laser desorption/ionization behavior of a thermometer molecule. Based on these characteristics, BGO exhibits higher efficiency in the LDI-TOF-MS analysis of various small molecules and synthetic polymers than HGO. These different photochemical properties of BGO are derived from its large sp2 carbon domains compared to HGO. Based on our findings, the analytical potential of LDI-TOF-MS for GO derivatives is clearly demonstrated, which can be an efficient and unique characterization tool to explore both chemical structures and photochemical properties of various carbon materials.

4.
Plants (Basel) ; 10(12)2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34961292

RESUMO

Exogenous glycine betaine (GB) application has been reported to improve plant tolerance to various abiotic stresses, but its effect on freezing tolerance has not been well studied. We investigated the effect of exogenous GB on freezing tolerance of cabbage (Brassica oleracea L.) leaves. Seedlings fed with 30 mM GB via sub-irrigation showed effectively assimilated GB as evident by higher GB concentration. Exogenous GB did not retard leaf-growth (fresh weight, dry weight, and leaf area) rather slightly promoted it. Temperature controlled freeze-thaw tests proved GB-fed plants were more freeze-tolerant as indicated by lower electrolyte leakage (i.e., indication of less membrane damage) and alleviating oxidative stress (less accumulation of O2•- and H2O2, as well as of malondialdehyde (MDA)) following a relatively moderate or severe freeze-thaw stress, i.e., -2.5 and -3.5 °C. Improved freezing tolerance induced by exogenous GB application may be associated with accumulation of compatible solute (proline) and antioxidant (glutathione). GB-fed leaves also had higher activity of antioxidant enzymes, catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD). These changes, together, may improve freezing tolerance through membrane protection from freeze-desiccation and alleviation of freeze-induced oxidative stress.

5.
Ecotoxicol Environ Saf ; 222: 112544, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34325195

RESUMO

Toxicological studies of O-ethyl-O-(4-nitrophenyl) phenylphosphonothioate (EPN) to aquatic vertebrates have been reported, but no reports on toxic mechanism was reported. As zebrafish (Danio rerio) embryos were exposed to EPN, no changes in their survival and hatching rates were observed until 96 h post fertilization (hpf), even at the highest treated concentration of 500 µg/L. In both 250 µg/L and 500 µg/L, edemas were observed in the heart and yolk sac, and a blood pool was also found. Acridine orange staining confirmed apoptotic phynotype, which was the strongest in embryos at 48 hpf. No noticeable difference in the formation and the shape of blood vessels of Tg(fli1a:EGFP) was observed. However, the total body length and number of somite were decreased. Heart formation in Tg(cmlc2:EGFP) were not properly proceeded, and the ventricle did not beat normally at 500 µg/L level. Cardiac development-related genes, myl7 and nppa, were significantly down- and up-regulated in a concentration-dependent manner. The slowed heartbeat was confirmed using Tg(gata1:EGFP), showing stagnant blood flow and seizure-like events were observed. Altogether, EPN can be the cause for the abnormal heart development accompanied by blood stagnation in embryos, interfering normal development with their inner circulatory system.


Assuntos
Inseticidas , Poluentes Químicos da Água , Animais , Embrião não Mamífero , Coração , Inseticidas/toxicidade , Convulsões , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
6.
Int J Mol Sci ; 22(5)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800290

RESUMO

Tumor necrosis factor alpha (TNF-α) was initially recognized as a factor that causes the necrosis of tumors, but it has been recently identified to have additional important functions as a pathological component of autoimmune diseases. TNF-α binds to two different receptors, which initiate signal transduction pathways. These pathways lead to various cellular responses, including cell survival, differentiation, and proliferation. However, the inappropriate or excessive activation of TNF-α signaling is associated with chronic inflammation and can eventually lead to the development of pathological complications such as autoimmune diseases. Understanding of the TNF-α signaling mechanism has been expanded and applied for the treatment of immune diseases, which has resulted in the development of effective therapeutic tools, including TNF-α inhibitors. Currently, clinically approved TNF-α inhibitors have shown noticeable potency in a variety of autoimmune diseases, and novel TNF-α signaling inhibitors are being clinically evaluated. In this review, we briefly introduce the impact of TNF-α signaling on autoimmune diseases and its inhibitors, which are used as therapeutic agents against autoimmune diseases.


Assuntos
Doenças Autoimunes , Fatores Imunológicos/uso terapêutico , Transdução de Sinais , Fator de Necrose Tumoral alfa , Animais , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Doença Crônica , Humanos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/imunologia
7.
J Phys Chem B ; 124(41): 8984-8988, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32946246

RESUMO

The behavior of cinnamycin on a biomimetic membrane was studied with respect to the curvature of a phosphatidylethanolamine (PE)-included membrane with the adhesion measured using an atomic force microscope (AFM). The membrane was formed through vesicle fusion on the hydrophobic surface of silica spheres, which was used to define the curvature of the membrane. The hydrophobicity was generated by the reaction of alkyl-silane and analyzed with an X-ray photoelectron spectrometer. The cinnamycin, immobilized covalently to the AFM tip coated with 1-mercapto-1-undecanol that was observed to be inert to any adhesion to the membrane, showed that the adhesion became stronger with the increase in the curvature. The correlation between the adhesion and the curvature was linearly proportional. Since it was found that the cinnamycin was bound to a PE headgroup and the binding was enhanced by the interaction of the hydrophobic area located at one side of the cinnamycin, the linear proportionality seems to suggest that the interaction is related to the one dimensional orientation of the binding.


Assuntos
Bacteriocinas , Fosfatidiletanolaminas , Fusão de Membrana , Microscopia de Força Atômica , Peptídeos Cíclicos
8.
ChemMedChem ; 15(23): 2257-2263, 2020 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-32924264

RESUMO

Chalcones are considered effective templates for the development of monoamine oxidase (MAO) and cholinesterase (ChE) inhibitors. The present work describes the syntheses of selected 1,3-benzodioxine-containing chalcones (CD3, CD8 and CD10), and their inhibitory activities against MAO-A, MAO-B, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE). Compound CD8 most potently inhibited MAO-B with an IC50 value of 0.026 µM, followed by CD10 and CD3 (1.54 and 1.68 µM, respectively). CD8 potently and non-selectively inhibited MAO-A (IC50 value of 0.023 µM). On the other hand, CD10 and CD8 inhibited AChE with IC50 values of 5.40 and 9.57 µM, respectively. Kinetics and reversibility experiments showed that all synthesized molecules were competitive and reversible inhibitors, and the Ki values of CD8 for MAO-A and MAO-B were 0.018 and 0.0019 µM, respectively. By in vitro and in silico analyses, all compounds were found to have high passive human gastrointestinal absorptions, blood-brain barrier permeabilities, and non-toxicities. Molecular docking simulations revealed that docking affinity of each compound for MAO-B was higher than that for MAO-A. The results indicate that CD8 is a potent non-selective MAO inhibitor, and CD10 is an effective selective MAO-B inhibitor, and both possess AChE inhibitory activity. Therefore, we suggest that CD8 and CD10 be considered potential dual-targeting inhibitors of MAO and AChE for the treatment of various neurodegenerative disorders.


Assuntos
Benzoxazinas/farmacologia , Chalconas/farmacologia , Inibidores da Colinesterase/farmacologia , Inibidores da Monoaminoxidase/farmacologia , Acetilcolinesterase/metabolismo , Benzoxazinas/química , Butirilcolinesterase/metabolismo , Chalconas/química , Inibidores da Colinesterase/química , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Monoaminoxidase/metabolismo , Inibidores da Monoaminoxidase/química
9.
Molecules ; 25(17)2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32859055

RESUMO

Eight compounds were isolated from the roots of Glycyrrhiza uralensis and tested for cholinesterase (ChE) and monoamine oxidase (MAO) inhibitory activities. The coumarin glycyrol (GC) effectively inhibited butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) with IC50 values of 7.22 and 14.77 µM, respectively, and also moderately inhibited MAO-B (29.48 µM). Six of the other seven compounds only weakly inhibited AChE and BChE, whereas liquiritin apioside moderately inhibited AChE (IC50 = 36.68 µM). Liquiritigenin (LG) potently inhibited MAO-B (IC50 = 0.098 µM) and MAO-A (IC50 = 0.27 µM), and liquiritin, a glycoside of LG, weakly inhibited MAO-B (>40 µM). GC was a reversible, noncompetitive inhibitor of BChE with a Ki value of 4.47 µM, and LG was a reversible competitive inhibitor of MAO-B with a Ki value of 0.024 µM. Docking simulations showed that the binding affinity of GC for BChE (-7.8 kcal/mol) was greater than its affinity for AChE (-7.1 kcal/mol), and suggested that GC interacted with BChE at Thr284 and Val288 by hydrogen bonds (distances: 2.42 and 1.92 Å, respectively) beyond the ligand binding site of BChE, but that GC did not form hydrogen bond with AChE. The binding affinity of LG for MAO-B (-8.8 kcal/mol) was greater than its affinity for MAO-A (-7.9 kcal/mol). These findings suggest GC and LG should be considered promising compounds for the treatment of Alzheimer's disease with multi-targeting activities.


Assuntos
Butirilcolinesterase/química , Inibidores da Colinesterase , Cumarínicos , Flavanonas , Glycyrrhiza uralensis/química , Inibidores da Monoaminoxidase , Monoaminoxidase/química , Animais , Inibidores da Colinesterase/química , Inibidores da Colinesterase/isolamento & purificação , Cumarínicos/química , Cumarínicos/isolamento & purificação , Electrophorus , Flavanonas/química , Flavanonas/isolamento & purificação , Humanos , Inibidores da Monoaminoxidase/química , Inibidores da Monoaminoxidase/isolamento & purificação
10.
Chemosphere ; 260: 127622, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673875

RESUMO

In this study, fluorene (FL), FL-1-carboxylic acid (FC-1), and FL-9-carboxylic acid (FC-9) were investigated to understand their acute toxicity by measuring inhibitory effects on hatching rates and developmental processes of zebrafish embryos (Danio rerio). For exposure concentrations up to 3000 µg/L, FC-1 alone showed acute toxicity at 1458 µg/L for LC50 value. FC-1 caused yolk sac and spinal deformities, and pericardial edema. Molecular studies were undertaken to understand FC-1 toxicity examining 61 genes after exposure to 5 µM (equivalent to LC20 value of FC-1) in embryos. In the FC-1-treated embryos, the expression of the cyp7a1 gene, involved in bile acid biosynthesis, was dramatically decreased, while the expression of the Il-1ß gene involved in inflammation was remarkably increased. In addition to these findings, in FC-1-treated embryos, the expression of nppa gene related to the differentiation of the myocardium was 3-fold increased. On the other hand, cyp1a, cyp3a, ugt1a1, abcc4, mdr1, and sult1st1 responsible for detoxification of xenobiotics were upregulated in FC-9-treated embryos. Taken together, carboxylation on carbon 1 of FL increased acute toxicity in zebrafish embryos, and its toxicity might be related to morphological changes with modification of normal biological functions and lowered defense ability.


Assuntos
Fluorenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ácidos Carboxílicos/metabolismo , Embrião não Mamífero/efeitos dos fármacos , Fluorenos/metabolismo , Peixe-Zebra/metabolismo
11.
J Biotechnol ; 320: 77-79, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32593691

RESUMO

The binding of the cinnamycin on the biomimetic membrane was studied with respect to time using the surface plasmon resonance(SPR). The membrane was composed of the inner layer tethered on the gold surface and the outer layer formed on the inner layer, which was at the desired ratio of dioleoylphosphatidylethanolamine(DOPE) to dioleoylphosphatidyl- choline(DOPC). On the bilayer, the cinnamycin solution was injected and showed different behavior of the binding with respect to time up on its concentration. For kinetic analysis, the behavior was converted to the coverage fraction with respect to time, which was ratio to the saturated response of 5 µM cinnamycin solution. The fraction change with respect to time was function of the available-site, which was eventually the subtraction of the fraction from one. With the fitting of the first order of the available site, the rate constant was acquired into 6∼7 × 10-3 s-1. Furthermore, the reciprocals of the fraction and the concentration were fitted with the Langmuir adsorption isotherm. From the fitting, the equilibrium constant was between 1 × 107 and 5 × 107 M-1.


Assuntos
Bacteriocinas , Membranas Artificiais , Peptídeos Cíclicos , Fosfatidiletanolaminas , Ressonância de Plasmônio de Superfície/métodos , Adsorção , Bacteriocinas/química , Bacteriocinas/metabolismo , Cinética , Peptídeos Cíclicos/química , Peptídeos Cíclicos/metabolismo , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/química , Fosfatidiletanolaminas/metabolismo , Termodinâmica
12.
J Environ Manage ; 234: 154-158, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30616187

RESUMO

Accumulation of solid waste has intensified with the increase in world population and industrialization. Most importantly, wastes of animal origin such as animal manures and tannery wastes are a major under-utilized resource in most countries with potential for utilization in crop production. This study evaluated the potential of solid state hydrolyzed tannery animal fleshing (SSF-ANFL) and submerged state hydrolyzed tannery ANFL (SmF-ANFL) vermicompost and compost amended soils on the growth, yield and chemical characteristics of tomatoes. It was interesting to observe that of most measured parameters, the SSF amended treatments resulted in significantly (P < 0.05) the highest measurements compared to the SmF amended treatments. On average, the SSF vermicompost resulted in a 10%, 8.9% and 14% higher plant height, stem girth and leaf numbers, respectively, compared to other treatments combined. It was also noteworthy that, for the same parameters, the SSF-ANFL based treatments resulted in a 7.7%, 10.1% and 7.4% higher plant height, stem girth and leaf numbers, respectively, relative to the SmF-ANFL based treatments. The study demonstrates the potential of animal fleshing based vermicomposts as nutrient sources in crop production.


Assuntos
Compostagem , Solanum lycopersicum , Animais , Esterco , Solo , Resíduos Sólidos
13.
J Environ Manage ; 232: 592-599, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30517840

RESUMO

Excessive nutrients and toxic gas emissions from animal manure management are of great global concern, with negative environmental and economic consequences worldwide. Due to biochar recalcitrance and sorption properties, this study investigated the effect of the biochar(BC) derived from bamboo, amendment on swine manure(SM) composting efficiency through physical, physio-chemical, gaseous emissions, microbiological, and phytotoxic analysis during the 56 day process of in-vessel composting. The treatments were set-up from different ratios of biochar to swine manure mixed with sawdust(SD)(i.e. SM + SD + 3%BC(T1), SM:SD + 5 %BC(T2) and SM:SD + 10 %BC (T3)), while treatment without biochar amendment was used as a control, SM:SD(C). The results showed that, compared to the control, biochar amended compost mixtures had significantly reduced (p ≤ 0.05) bulk density, organic matter(OM), C:N ratio, NH3 emission, pathogenic microorganisms, and phytotoxicity effect (Cress seed, Lepidium sativum Linn.). On the other hand, biochar amendment mixtures had increased total porosity, water holding capacity, rapid thermophilic temperature, and nitrate nitrogen. However, with the most prominent effects in terms of the nutrient quality and degradation rate of compost mixtures, the amendment of 10% biochar is recommended for swine manure management through the composting process.


Assuntos
Compostagem , Microbiota , Animais , Carvão Vegetal , Esterco , Nitrogênio , Solo , Suínos
14.
J Membr Biol ; 251(5-6): 705-709, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30196445

RESUMO

The effect of the trehalose on the physical properties of the fluidic lipid bilayer was studied using surface plasmon resonance (SPR) and cyclic voltammetry (CV). The bilayer was fabricated by tethering 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol on a gold surface to form a monolayer and then using liposomes to adsorb an upper layer on the tethered monolayer. The liposomes were prepared with a desired ratio (mol/mol) of trehalose to lipid, before the adsorption was performed. The formation of the adsorbed layer was monitored with SPR, and the SPR responses were converted to the surface density of the layer. In addition, the CV measurement was conducted to acquire the current-potential responses to evaluate the charge permeability of the layer. The surface density was gradually increased with the trehalose ratio up to 0.5, while the charge permeability was decreased. From these changes, the trehalose appears to be related to the curvature generation induced by the trehalose, which is consistent with the previous simulation results. In the identical measurements at glucose, little change in the properties was observed with even up to 2:1 ratio of glucose:lipid. These results seem attributed to the osmotic and volumetric effect on the headgroup packing disruption. The present study may provide a unique platform to control biological functions related to cellular processes.


Assuntos
Bicamadas Lipídicas/química , Trealose/química , Glucose/química , Lipossomos/química , Ressonância de Plasmônio de Superfície , Propriedades de Superfície , Triglicerídeos/química
15.
J Pharmacopuncture ; 21(2): 98-103, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30151310

RESUMO

OBJECTIVE: DIt is need to evaluate he changes of the bio-signals through the hot-cold stimulation in the CV4. METHODS: The 30 healthy participants were enrolled and randomly allocated, to one of three groups(10 participants for each group): the hot stone therapy(HST) group, or the cold stone therapy(CST) group or no treatment group(NT). All the participants took a rest for 10 minutes for stability before the test. And additional 10 minute rest after measurements of skin test and sEMG. After that two group received hot or cold stone therapy for 30 minutes and one group treated nothing with HRV test. RESULTS: HRV LF value showed a significant increase over time in all three groups, but there was no significant difference between groups but HRV HF value did not show any significant difference with time in all three groups and there was no significant difference between groups. sEMG value showed a significant increase in the left side of the masseter muscle of the HST group and sebum levels was a significant decreased in HST group but no significant meaning was found. CONCLUSION: There was no objective evidence that hot-cold stimulation produced bio-signals changes in comparison to the control group, but additional studies are needed as the subjects were limited.

16.
Sci Total Environ ; 615: 70-77, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28963897

RESUMO

To develop the environmentally benign thermo-chemical process, this study placed great emphasis on the influence of CO2 on pyrolysis of cattle excreta for energy recovery. To this end, this study evaluates the possible enhanced energy recovery from cattle excreta using CO2 as reaction medium/feedstock in the thermal degradation of cattle excreta. The enhanced generation of CO in the presence of CO2 reached up to 15.15mol% (reference value: 0.369mol%) at 690°C, which was equivalent to ~4000 times more generation of CO. In addition to the enhanced generation of CO, the enhanced generation of H2 and CH4 in the thermal degradation of cattle excreta in CO2. Thus, the findings of this study revealed two genuine roles of CO2: 1) enhanced thermal cracking of volatile organic carbons (VOCs) evolved from the thermal degradation of cattle excreta and 2) direct reaction between VOCs and CO2 via gas phase reaction.

17.
Sci Total Environ ; 610-611: 992-996, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-28838036

RESUMO

This report proposes a new approach to evaluate the odour nuisance of cattle manure samples from three different cattle breeds (i.e., native cattle, beef cattle, and milk cow) by means of quantification and speciation of volatile fatty acids (VFAs). To this end, non-catalytic esterification thermally induced in the presence of a porous material (silica) was undertaken, and the optimal operational parameters such as the derivatizing temperature (330°C) for the maximum yield (≥99±0.4%) of volatile fatty acid methyl esters (VFAMEs) were established. Among the VFA species in cattle manure based on quantification of VFAs, the major species were acetic, butyric and valeric acid. Considering the odour threshold of each VFA, our experimental results suggested that the major contributors to odour nuisance were C4-5 VFA species (i.e., butyric and valeric acid). Hydrothermal treatment was performed at 150°C for 0-40min to correlate the formation of VFAs with different types of cattle feed formulations. Our experimental data demonstrated that the formation of total VFAs is linearly proportional to the hydrothermal treatment duration and the total content of VFAs in native cattle, beef cattle, and milk cow manure samples reached up to ~1000, ~3200, and ~2800ppm, respectively. Thus, this study demonstrated that the degree of VFA formation is highly dependent on cattle feed formulations, which rely significantly on the protein content. Furthermore, the hydrothermal treatment provides a favourable condition for generating more VFAs. In this context, producing cattle manure into refused derived fuel (RDF) via a hydrothermal treatment is not a viable option to control odour.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Ácidos Graxos Voláteis/análise , Esterco/análise , Odorantes/análise , Animais , Bovinos , Esterificação
18.
Bioresour Technol ; 244(Pt 1): 810-815, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28841785

RESUMO

This study laid an emphasis on the possible employment of biochar generated from pyrolysis of chicken manure to establish a green platform for producing biodiesel. To this end, the pseudo-catalytic transesterification reaction using chicken manure biochar and waste cooking oil was investigated. Compared with a commercial porous material (SiO2), chicken manure biochar generated from 350°C showed better performance, resulting in 95.6% of the FAME yield at 350°C. The Ca species in chicken manure biochar imparted strong catalytic capability by providing the basicity for transesterification. The identified catalytic effect also led to the thermal cracking of unsaturated FAMEs, which decreased the overall FAME yield. For example, 40-60% of converted FAMEs were thermally degraded. To avoid undesirable thermal cracking arising from the high content of the Ca species in chicken manure biochar, the fabrication of chicken manure biochar at temperatures ≥350°C was highly recommended.


Assuntos
Biocombustíveis , Carvão Vegetal , Esterco , Animais , Galinhas , Culinária , Dióxido de Silício
19.
Environ Pollut ; 230: 81-86, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28649044

RESUMO

This study lays great emphasis on establishing a reliable analytical platform to quantify and specify volatile fatty acids (VFAs) in the aqueous phase by derivatizing VFAs into their corresponding alkyl esters via thermally-induced rapid esterification (only 10 s reaction time). To this end, reaction conditions for the thermally-induced rapid esterification are optimized. A volumetric ratio of 0.5 at 400 °C for VFA/methanol is identified as the optimal reaction conditions to give ∼90% volatile fatty acid methyl ester (VFAME) yield. To maintain a high yield of VFAMEs, this study suggests that dilution of the sample to an optimum concentration (∼500 ppm for each VFA) is required. Derivatization of VFAs into VFAMEs via the thermally-induced rapid esterification is more reliable to quantify and specify VFAs in the aqueous phase than conventional colorimetric method.


Assuntos
Fracionamento Químico/métodos , Ácidos Graxos Voláteis/análise , Poluentes Químicos da Água/análise , Esterificação , Ácidos Graxos , Ácidos Graxos Voláteis/química , Poluentes Químicos da Água/química
20.
Bioresour Technol ; 231: 59-64, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28196780

RESUMO

This study focuses on investigating the optimized chemical composition of biochar used as porous material for biodiesel synthesis via pseudo-catalytic transesterification. To this end, six biochars from different sources were prepared and biodiesel yield obtained from pseudo-catalytic transesterification of waste cooking oil using six biochars were measured. Biodiesel yield and optimal reaction temperature for pseudo-catalytic transesterification were strongly dependent on the raw material of biochar. For example, biochar generated from maize residue exhibited the best performance, which yield was reached ∼90% at 300°C; however, the maximum biodiesel yield with pine cone biochar was 43% at 380°C. The maximum achievable yield of biodiesel was sensitive to the lignin content of biomass source of biochar but not sensitive to the cellulose and hemicellulose content. This study provides an insight for screening the most effective biochar as pseudo-catalytic porous material, thereby helping develop more sustainable and economically viable biodiesel synthesis process.


Assuntos
Biocombustíveis , Carvão Vegetal/farmacologia , Biomassa , Catálise/efeitos dos fármacos , Celulose/análise , Culinária , Esterificação/efeitos dos fármacos , Ésteres/análise , Lignina/análise , Óleos/química , Polissacarídeos/análise , Porosidade , Temperatura , Resíduos/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA