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1.
Int J Legal Med ; 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38858273

RESUMEN

Monozygotic (MZ) twins cannot be distinguished using conventional forensic STR typing because they present identical STR genotypings. However, MZ twins do not always live in the same environment and often have different dietary and other lifestyle habits. Metabolic profiles are deyermined by individual characteristics and are also influenced by the environment in which they live. Therefore, they are potential markers capable of identifying MZ twins. Moreover, the production of proteins varies from organism to organism and is influenced by both the physiological state of the body and the external environment. Hence, we used metabolomics and proteomics to identify metabolites and proteins in peripheral blood to discriminate MZ twins. We identified 1749 known metabolites and 622 proteins in proteomic analysis. The metabolic profiles of four pairs of MZ twins revealed minor differences in intra-MZ twins and major differences in inter-MZ twins. Each pair of MZ twins exhibited distinct characteristics, and four metabolites-methyl picolinate, acesulfame, paraxanthine, and phenylbenzimidazole sulfonic acid-were observed in all four MZ twin pairs. These four differential exogenous metabolites conincidently show that the different external environments and life styles can be well distinguished by metabolites, considering that twins do not all have the same eating habits and living environments. Moreover, MZ twins showed different protein profiles in serum but not in whole blood. Thus, our results indicate that differential metabolites provide potential biomarkers for the personal identification of MZ twins in forensic medicine.

2.
Int J Legal Med ; 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38802694

RESUMEN

In forensic practice, determining the postmortem submersion interval (PMSI) and cause-of-death of cadavers in aquatic ecosystems has always been challenging task. Traditional approaches are not yet able to address these issues effectively and adequately. Our previous study proposed novel models to predict the PMSI and cause-of-death based on metabolites of blood from rats immersed in freshwater. However, with the advance of putrefaction, it is hardly to obtain blood samples beyond 3 days postmortem. To further assess the feasibility of PMSI estimation and drowning diagnosis in the later postmortem phase, gastrocnemius, the more degradation-resistant tissue, was collected from drowned rats and postmortem submersion model in freshwater immediately after death, and at 1 day, 3 days, 5 days, 7 days, and 10 days postmortem respectively. Then the samples were analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate the dynamic changes of the metabolites. A total of 924 metabolites were identified. Similar chronological changes of gastrocnemius metabolites were observed in the drowning and postmortem submersion groups. The difference in metabolic profiles between drowning and postmortem submersion groups was only evident in the initial 1 day postmortem, which was faded as the PMSI extension. Nineteen metabolites representing temporally-dynamic patterns were selected as biomarkers for PMSI estimation. A regression model was built based on these biomarkers with random forest algorithm, which yielded a mean absolute error (± SE) of 5.856 (± 1.296) h on validation samples from an independent experiment. These findings added to our knowledge of chronological changes in muscle metabolites from submerged vertebrate remains during decomposition, which provided a new perspective for PMSI estimation.

3.
Ann Hum Biol ; 51(1): 1-9, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38251838

RESUMEN

BACKGROUND: As a new kind of diallelic genetic marker, insertion/deletion (InDel) polymorphisms have recently been used in forensic science. However, there are relatively few studies on the forensic evaluation of InDel genetic polymorphisms from different populations. AIM: The aim of the present work is to assess the genetic polymorphism and forensic applicability of 57 InDels from the Yi ethnic group and explore the genetic background of this group. SUBJECTS AND METHODS: A total sample of 122 unrelated individuals of Yi group from the Yunnan province were genotyped by the AGCU indel 60 Kit. Multiplex population genetic analyses on the same 57 InDels were carried out among the Yunnan Yi group and 29 reference populations. RESULTS: The average allele frequency of these loci in the Yi ethnic group was 0.485. Heterozygosity, polymorphism information content, and the power of discrimination were 0.477, 0.362, and 0.612, respectively. The combined power of discrimination and the combined power of exclusion reached to 0.99999999999999999669 and 0.999962965, respectively. The results showed that 57 InDels polymorphisms have high genetic polymorphisms in the Yi ethnic group. CONCLUSIONS: The 57 InDels could be used for forensic individual identification, paternity testing, and intercontinental population discrimination, with the potential for use in biogeographic ancestry inference.


Asunto(s)
Etnicidad , Polimorfismo Genético , Humanos , Etnicidad/genética , China , Frecuencia de los Genes , Genotipo
4.
Int J Legal Med ; 137(5): 1337-1345, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37270462

RESUMEN

Differentiating between monozygotic (MZ) twins remains difficult because they have the same genetic makeup. Applying the traditional STR genotyping approach cannot differentiate one from the other. Heteroplasmy refers to the presence of two or more different mtDNA copies within a single cell and this phenomenon is common in humans. The levels of heteroplasmy cannot change dramatically during transmission in the female germ line but increase or decrease during germ-line transmission and in somatic tissues during life. As massively parallel sequencing (MPS) technology has advanced, it has shown the extraordinary quantity of mtDNA heteroplasmy in humans. In this study, a probe hybridization technique was used to obtain mtDNA and then MPS was performed with an average sequencing depth of above 4000. The results showed us that all ten pairs of MZ twins were clearly differentiated with the minor heteroplasmy threshold at 1.0%, 0.5%, and 0.1%, respectively. Finally, we used a probe that targeted mtDNA to boost sequencing depth without interfering with nuclear DNA and this technique can be used in forensic genetics to differentiate the MZ twins.


Asunto(s)
ADN Mitocondrial , Genoma Mitocondrial , Femenino , Humanos , ADN Mitocondrial/genética , Heteroplasmia , Secuenciación de Nucleótidos de Alto Rendimiento , Análisis de Secuencia de ADN , Gemelos Monocigóticos/genética
5.
Environ Sci Technol ; 57(16): 6485-6493, 2023 04 25.
Artículo en Inglés | MEDLINE | ID: mdl-37043626

RESUMEN

Biomass pyrolysis within the alkaline molten salt is attractive due to its ability to achieve high hydrogen yield under relatively mild conditions. However, poor contact between biomass, especially the biomass pellet, and hydroxide during the slow heating process, as well as low reaction temperatures, become key factors limiting the hydrogen production. To address these challenges, fast pyrolysis of the algae pellet in molten NaOH-Na2CO3 was conducted at 550, 650, and 750 °C. Algae were chosen as feedstock for their high photosynthetic efficiency and growth rate, and the concept of coupling molten salt with concentrated solar energy was proposed to address the issue of high energy consumption at high temperatures. At 750 °C, the pollutant gases containing Cl and S were completely removed, and the HCN removal rate reached 44.92%. During the continuous pyrolysis process, after a slight increase, the hydrogen yield remained stable at 71.48 mmol/g-algae and constituted 86.10% of the gas products, and a minimum theoretical hydrogen production efficiency of algae can reach 84.86%. Most importantly, the evolution of physicochemical properties of molten NaOH-Na2CO3 was revealed for the first time. Combined with the conversion characteristics of feedstock and gas products, this study provides practical guidance for large-scale application of molten salt including feedstock, operation parameters, and post-treatment process.


Asunto(s)
Gases , Pirólisis , Hidróxido de Sodio , Calor , Cloruro de Sodio , Hidrógeno , Biomasa
6.
Environ Sci Technol ; 55(9): 6373-6385, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33844510

RESUMEN

Algae pyrolytic bio-oil contains a large quantity of N-containing components (NCCs), which can be processed as valuable chemicals, while the harmful gases can also be released during bio-oil upgrading. However, the characteristics of NCCs in the bio-oil, especially the composition of heavy NCCs (molecular weight ≥200 Da), have not been fully studied due to the limitation of advanced analytical methods. In this study, three kinds of algae rich in lipids, proteins, and carbohydrates were rapidly pyrolyzed (10-25 °C/s) at different temperatures (300-700 °C). The bio-oil was analyzed using a Fourier transform ion cyclotron resonance mass spectrometer equipped with electrospray ionization, and the characteristics and evolution of nitrogen in heavy components were first obtained. The results indicated that the molecular weight of most heavy NCCs was distributed in the 200-400 Da range. N1-3 compounds account for over 60% in lipid and protein-rich samples, while N0 and N4 components are prominent in carbohydrate-rich samples. As temperature increases, most NCCs become more aromatic and contain less O due to the strong Maillard and deoxygenation reactions. Moreover, the heavier NCCs were promoted to form lighter compounds with more nitrogen atoms through decomposition (mainly denitrogenation and deoxygenation). Finally, some strategies to deal with the NCCs for high-quality bio-oil production were proposed.


Asunto(s)
Nitrógeno , Pirólisis , Biocombustibles , Biomasa , Calor , Aceites de Plantas , Polifenoles
8.
Neuromolecular Med ; 25(1): 53-63, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-35767210

RESUMEN

Sirtuin-6 (SIRT6), a member of the sirtuins family of NAD ( +) dependent deacetylases, has been shown to have beneficial effects in ischemic stroke. However, the role of SIRT6 in intracerebral haemorrhage (ICH) has not reported. We observed that SIRT6 expression was down-regulated in human ICH patients and down-regulated in ICH-induced rat cortical neurons. We subsequently found that SIRT6 overexpression reduced brain tissue damage and increased neuronal survival in the ICH model of rats and hemin-induced cortical neurons. Our further study found that overexpression of SIRT6 can reduce inflammatory response by down-regulating the expression of NF-kB and thus promote the recovery of neurological function in ICH animals. In conclusion, SIRT6 can inhibit the expression of NF-kB and plays a neuroprotective role in ICH by inhibiting the NF-kB-mediated inflammatory response.SIRT6 could be a novel therapeutic target for ICH.


Asunto(s)
FN-kappa B , Sirtuinas , Ratas , Humanos , Animales , FN-kappa B/metabolismo , Hemorragia Cerebral/genética , Hemorragia Cerebral/metabolismo , Neuroprotección , Sirtuinas/genética
9.
Front Microbiol ; 13: 1052808, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36458191

RESUMEN

Introduction: Bodies recovered from water, especially in the late phase of decomposition, pose difficulties to the investigating authorities. Various methods have been proposed for postmortem submersion interval (PMSI) estimation and drowning identification, but some limitations remain. Many recent studies have proved the value of microbiota succession in viscera for postmortem interval estimation. Nevertheless, the visceral microbiota succession and its application for PMSI estimation and drowning identification require further investigation. Methods: In the current study, mouse drowning and CO2 asphyxia models were developed, and cadavers were immersed in freshwater for 0 to 14 days. Microbial communities in the liver and brain were characterized via 16S rDNA high-throughput sequencing. Results: Only livers and brains collected from 5 to 14 days postmortem were qualified for sequencing. There was significant variation between microbiota from liver and brain. Differences in microbiota between the cadavers of mice that had drowned and those only subjected to postmortem submersion decreased over the PMSI. Significant successions in microbial communities were observed among the different subgroups within the late phase of the PMSI in livers and brains. Eighteen taxa in the liver which were mainly related to Clostridium_sensu_stricto and Aeromonas, and 26 taxa in the brain which were mainly belonged to Clostridium_sensu_stricto, Acetobacteroides, and Limnochorda, were selected as potential biomarkers for PMSI estimation based on a random forest algorithm. The PMSI estimation models established yielded accurate prediction results with mean absolute errors ± the standard error of 1.282 ± 0.189 d for the liver and 0.989 ± 0.237 d for the brain. Conclusions: The present study provides novel information on visceral postmortem microbiota succession in corpses submerged in freshwater which sheds new light on PMSI estimation based on the liver and brain in forensic practice.

10.
Front Microbiol ; 13: 988297, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36532467

RESUMEN

Microbial community succession during decomposition has been proven to be a useful tool for postmortem interval (PMI) estimation. Numerous studies have shown that the intestinal microbial community presented chronological changes after death and was stable in terrestrial corpses with different causes of death. However, the postmortem pattern of intestinal microbial community succession in cadavers retrieved from water remains unclear. For immersed corpses, the postmortem submersion interval (PMSI) is a useful indicator of PMI. To provide reliable estimates of PMSI in forensic investigations, we investigated the gut microbial community succession of corpses submersed in freshwater and explored its potential application in forensic investigation. In this study, the intestinal microbial community of mouse submersed in freshwater that died of drowning or CO2 asphyxia (i.e., postmortem submersion) were characterized by 16S rDNA amplification and high-throughput sequencing, followed by bioinformatic analyses. The results demonstrated that the chronological changes in intestinal bacterial communities were not different between the drowning and postmortem submersion groups. α-diversity decreased significantly within 14 days of decomposition in both groups, and the ß-diversity bacterial community structure ordinated chronologically, inferring the functional pathway and phenotype. To estimate PMSI, a regression model was established by random forest (RF) algorithm based on the succession of postmortem microbiota. Furthermore, 15 genera, including Proteus, Enterococcus, and others, were selected as candidate biomarkers to set up a concise predicted model, which provided a prediction of PMSI [MAE (± SE) = 0.818 (± 0.165) d]. Overall, our present study provides evidence that intestinal microbial community succession would be a valuable marker to estimate the PMSI of corpses submerged in an aquatic habitat.

11.
Vaccines (Basel) ; 10(2)2022 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-35214784

RESUMEN

(1) Background: Although there are extensive data on admission co-variates and outcomes of persons with coronavirus infectious disease-2019 (COVID-19) at diverse geographic sites, there are few, if any, subject-level comparisons between sites in regions and countries. We investigated differences in hospital admission co-variates and outcomes of hospitalized people with COVID-19 between Wuhan City, China and the New York City region, USA. (2) Methods: We retrospectively analyzed clinical data on 1859 hospitalized subjects with COVID-19 in Wuhan City, China, from 20 January to 4 April 2020. Data on 5700 hospitalized subjects with COVID-19 in the New York City region, USA, from 1 March to 4 April 2020 were extracted from an article by Richardson et al. Hospital admission co-variates (epidemiological, demographic, and laboratory co-variates) and outcomes (rate of intensive care unit [ICU] admission, invasive mechanical ventilation [IMV], major organ failure and death, and length of hospital stay) were compared between the cohorts. (3) Results: Wuhan subjects were younger, more likely female, less likely to have co-morbidities and fever, more likely to have a blood lymphocyte concentration > 1 × 109/L, and less likely to have abnormal liver and cardiac function tests compared with New York subjects. There were outcomes data on all Wuhan subjects and 2634 New York subjects. Wuhan subjects had higher blood nadir median lymphocyte concentrations and longer hospitalizations, and were less likely to receive IMV, ICU hospitalization, and interventions for kidney failure. Amongst subjects not receiving IMV, those in Wuhan were less likely to die compared with New York subjects. In contrast, risk of death was similar in subjects receiving IMV at both sites. (4) Conclusions: We found different hospital admission co-variates and outcomes between hospitalized persons with COVID-19 between Wuhan City and the New York region, which should be useful developing a comprehensive global understanding of the SARS-CoV-2 pandemic and COVID-19.

12.
J Mol Neurosci ; 70(11): 1851-1857, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32388801

RESUMEN

Schizophrenia is a serious neurodevelopmental disorder. Genetics is an important factor leading to schizophrenia, but its exact role is still unclear. Many studies have focused on neurotransmitters and regulators that participate in the processes mediated by these neurotransmitters. Alcohol dehydrogenase may not only catalyze the oxidation of retinol and ethanol but also be involved in a variety of neurotransmitter metabolic pathways. Therefore, our study investigated whether ADH7 gene variations in the Chinese Han population were associated with schizophrenia. Genomic DNA was extracted from a cohort of 275 schizophrenic patients (136 men and 139 women) and 313 healthy controls (160 men and 153 women) from the Northern Han Chinese population. The Hardy-Weinberg equilibrium test and linkage disequilibrium analysis were performed. Differences in genotypes, alleles, and haplotypes between the schizophrenic and control groups were determined using the chi-square test and correlation analysis. The distribution of the CC + TT genotype of rs284787 was statistically different between the case and control groups (p = 0.026, OR = 1.448); however, the difference disappeared after Bonferroni correction. Linkage analysis indicated that rs739147, rs284787, rs3805329, rs894369, rs3805331, and rs284786 were closely linked in one block. The haplotype analysis found no association between the composed haplotypes and the occurrence of schizophrenia. Our study showed that the ADH7 gene was not associated with the risk of schizophrenia. Additional studies with larger cohorts of different ethnicities are needed to validate our findings.


Asunto(s)
Alcohol Deshidrogenasa/genética , Polimorfismo de Nucleótido Simple , Esquizofrenia/genética , China , Femenino , Humanos , Desequilibrio de Ligamiento , Masculino
13.
J Int Med Res ; 48(6): 300060520932801, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32567430

RESUMEN

OBJECTIVE: Schizophrenia is a severe neurodevelopmental disorder with a complex genetic and environmental etiology. The gene encoding EF-hand domain-containing protein D2 (EFHD2) may be a genetic risk locus for schizophrenia. METHODS: We genotyped four EFHD2 single-nucleotide polymorphisms (281 schizophrenia cases [SCZ], 321 controls) from northern Chinese Han individuals using Sanger sequencing and polymerase chain reaction-restriction fragment length polymorphism analysis. Differences existed in genotype, allele, and haplotype frequency distributions between SCZ and control groups. RESULTS: The rs2473357 genotype and allele frequency distributions differed between SCZ and controls; however, this difference disappeared after Bonferroni correction. Differences in rs2473357 genotype and allele frequency distributions between SCZ and controls were more pronounced in men than in women. The G allele increased schizophrenia risk (odds ratio = 1.807, 95% confidence interval = 1.164-2.803). Among six haplotypes (G-, A-, G-insC, A-C, G-C, and G-T), the G- haplotype frequency distribution differed between SCZ and controls in women; the A-C and G-C haplotype frequency distributions differed between SCZ and controls in men. CONCLUSIONS: EFHD2 may be involved in schizophrenia. Sex differences in EFHD2 genotype and allele frequency distributions existed among schizophrenia patients. Further research is needed to determine the role of EFHD2 in schizophrenia.


Asunto(s)
Proteínas de Unión al Calcio/genética , Esquizofrenia/genética , Adulto , Alelos , Pueblo Asiatico/genética , Proteínas de Unión al Calcio/metabolismo , Estudios de Casos y Controles , China , Etnicidad/genética , Femenino , Frecuencia de los Genes/genética , Estudios de Asociación Genética/métodos , Predisposición Genética a la Enfermedad/genética , Genotipo , Haplotipos/genética , Humanos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Polimorfismo de Nucleótido Simple/genética
14.
Neuropsychiatr Dis Treat ; 16: 1519-1532, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32606704

RESUMEN

BACKGROUND: Epidemiological studies have shown that genetic factors are among the causes of schizophrenia. Galanin receptor 1 is an inhibitory receptor of galanin that is widely distributed in the central nervous system. This study mainly explored the relationship between polymorphisms of the 5' region of the GALR1 gene and schizophrenia in the northern Chinese Han population. METHODS: A 1545 bp fragment of the 5' regulatory region of the GALR1 gene was amplified and sequenced in 289 schizophrenia patients and 347 healthy controls. RESULTS: Among the haplotypes composed of the 16 detected SNPs, the haplotype H3 was identified as conferring a risk of schizophrenia (p=0.011, OR=1.430, 95% CI=1.084-1.886). In addition, the haplotypes H4 and H7 were both protective against schizophrenia (p=0.024, OR=0.526, 95% CI=0.298-0.927; p=0.037, OR=0.197, 95% CI=0.044-0.885, respectively). In the subgroup analysis by sex, it was found that seven SNP alleles (rs72978691, rs11662010, rs11151014, rs11151015, rs13306374, rs5373, rs13306375) conferred a risk of schizophrenia in females (p<0.05), while allele G of rs7242919 (p=0.007) was protective against schizophrenia in females. Moreover, the rs72978691 AA+AC genotype (p=0.006, OR=1.874, 95% CI=1.196-2.937, power=0.780), rs7242919 CC+CG genotype (p=0.002, OR=2.027, 95% CI=1.292-3.180, power=0.861), rs11151014 GG+GT genotype (p=0.008, OR=1.834, 95% CI=1.168-2.879, power=0.735), rs11151015 GG+AG genotype (p=0.002, OR=2.013, 95% CI =1.291-3.137, power=0.843), rs13306374 CC+AC genotype (p=0.006, OR=1.881, 95% CI=1.198-2.953, power=0.788), and rs13306375 GG+AG genotype (p=0.006, OR=1.868, 95% CI=1.194-2.921, power=0.770) increased the risk of schizophrenia in females. The haplotype FH2 consisting of rs72978691, rs11662010, rs7242919, rs11151014, rs11151015, rs13306374, rs5373, and rs13306375 may also be associated with the risk of schizophrenia in females (p=0.024). CONCLUSION: This study identified an association between polymorphisms in the 5' region of the GALR1 gene and schizophrenia, especially in females.

15.
Bioresour Technol ; 281: 309-317, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30826517

RESUMEN

Untreated corn stalk (CS), deionized water washed CS (WCS), aqueous phase bio-oil washed CS (LCS), and 5% acetic acid washed CS (CCS) were torrefied at 230, 260, and 290 °C. The influences of washing, torrefaction, and combined washing-torrefaction pretreatments on corn stalk pyrolysis were investigated. The combined pretreatments, especially aqueous phase bio-oil washing-torrefaction improved fuel properties of pretreated samples largely by increasing their volatile and hydrogen contents. Absorption peaks of O-H and CO groups in combined pretreatment samples increased when torrefaction temperature increased. In addition, CO, H2, and CH4 contents of pyrolysis gas increased, while CO2 decreased after combined pretreatments. The bio-oil yields from WCS290, LCS290, and CCS290 increased by 134.04%, 127.66%, and 129.79% respectively, compared with that from CS290. Similarly, their relative sugar contents (rich in levoglucosan) increased to 36.63%, 45.89%, and 52.34%, respectively. Aqueous phase oil washing-torrefaction is a promising pretreatment and acetic acid plays the most important role.


Asunto(s)
Aceites de Plantas/química , Polifenoles/química , Zea mays/química , Calor , Pirólisis , Agua
16.
Bioresour Technol ; 273: 77-85, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30415072

RESUMEN

In this study, the effects of a macroporous catalyst (CaO), mesoporous catalyst (MCM-41), and microporous catalysts (ZSM-5 and SAPO-34) on the production of light olefins and aromatics from cellulose catalytic fast pyrolysis were investigated in a dual-catalyst fixed bed reactor. Further the fractional catalytic pyrolysis of MCM-41 or CaO with ZSM-5 or SAPO-34 was explored. The results showed that ZSM-5 was the most efficient catalyst for the formation of light olefins and aromatics followed by MCM-41, CaO and SAPO-34, and no aromatics were found with SAPO-34 only. Moreover, 15% CaO combined 85% ZSM-5 produced the highest yield of light olefins (5.59%) and aromatic (13.42%). The addition of CaO and MCM-41 promoted the selectivity of C2H4 and decreased the production of naphthalene.


Asunto(s)
Alquenos/química , Celulosa/química , Biomasa , Catálisis , Pirólisis , Dióxido de Silicio/química , Zeolitas/química
17.
Bioresour Technol ; 289: 121729, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31323723

RESUMEN

The micropores present in ZSM-5 are beneficial to the production of aromatic compounds in biomass catalytic pyrolysis, although the small pore size leads to severe coke deposition on the catalyst. In this study, a micro-mesoporous structured ZSM-5 zeolite catalyst was synthesized and modified with green templates (sucrose, cellulose, and starch) to introduce additional mesopores. It was found that the catalysts modified using the sucrose and cellulose templates only exhibited a slight increase in their micropore volumes, while the mesopore volume of ZSM-ST (modified with the starch template) reached up to 0.359 cm3/g. This increase promoted the cracking of bulky oxygenates and suppressed the polymerization reaction on the ZSM-5 surface, thereby producing a greater number of aromatic products. Moreover, the benzene, toluene, and xylene (BTX) yields exhibited a positive correlation with the catalyst mesopore volume, with the highest BTX yield of 91.84 mg/g being obtained with 10% starch addition.


Asunto(s)
Pirólisis , Xilenos , Biomasa , Catálisis , Tolueno
18.
Bioresour Technol ; 278: 248-254, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30708327

RESUMEN

Biomass catalytic pyrolysis with various metals (Zn, Fe, Ca, Ce and La) modified ZSM-5 catalysts were analyzed, in order to investigate the relationship between the physicochemical properties of catalysts and the benzene, toluene and xylene (BTX) products. Results revealed that the BTX products were positively correlated with the strong acid site contents of the catalysts. Appropriate amount (0.5-4 wt%) of loaded Zn species increased the strong acid site contents of the catalysts as well as BTX yields, and the highest yield of BTX was observed under Zn loading amount of 2 wt%. While excessive metal loading amount (10 wt%) decreased both the acidity and the physical properties of the catalyst, resulting in poor diffusion of reactants and products in the channel and decreased the BTX yield. It is recommended that ZSM-5 catalyst with higher strong acid site content and pore volume should be used for BTX production.


Asunto(s)
Benceno/química , Tolueno/química , Xilenos/química , Zeolitas/química , Biomasa , Calcio/química , Catálisis , Fenómenos Químicos , Lantano/química , Metales Pesados/química , Pirólisis
19.
Sci Total Environ ; 628-629: 350-357, 2018 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-29453172

RESUMEN

Light olefins are the key building blocks for the petrochemical industry. In this study, the effects of in-situ and ex-situ process, temperature, Fe loading, catalyst to feed ratio and gas flow rate on the olefins carbon yield and selectivity were explored. The results showed that Fe-modified ZSM-5 catalyst increased the olefins yield significantly, and the ex-situ process was much better than in-situ. With the increasing of temperature, Fe-loading amount, catalyst to feed ratio, and gas flow rate, the carbon yields of light olefins were firstly increased and further decreased. The maximum carbon yield of light olefins (6.98% C-mol) was obtained at the pyrolysis temperature of 600°C, catalyst to feed ratio of 2, gas flow rate of 100ml/min, and 3wt% Fe/ZSM-5 for cellulose. The selectivity of C2H4 was more than 60% for all feedstock, and the total light olefins followed the decreasing order of cellulose, corn stalk, hemicelluloses and lignin.

20.
Bioresour Technol ; 261: 62-69, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29653335

RESUMEN

The study presented an approach to introduce Mg-based additives into cotton stalk for strengthening deoxygenation effect during torrefaction. Then catalytic pyrolysis of torrefied feedstock with Mg-based additives residue as catalyst was performed at 550 °C for 10 min in a fixed-bed reactor. The effects of torrefaction temperature (200, 230, 260, 290, 320, 350 °C), type of Mg-based additive (MgO and MgO-K2CO3), mass ratio of additive to biomass (0.5, 1 and 2) on pyrolysis were investigated. The results indicated that yields of bio-char and bio-oil significantly increased and decreased with torrefaction temperature rising to 350 °C. MgO inhibited pyrolysis bio-char yield increase with torrefaction severity. MgO-K2CO3 increased H2 yield a lot from 1.39 to 3.67 mmol/g. It also effectively improved the aromatic hydrocarbons in bio-oil and the reduction of acids. A maximum aromatic hydrocarbons yield of 16.05% was obtained with MgO-K2CO3 (the mass ratio of 0.5:1) at torrefaction temperature of 320 °C.


Asunto(s)
Biocombustibles , Hidrocarburos Aromáticos/metabolismo , Biomasa , Catálisis , Calor , Temperatura
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