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1.
Analyst ; 146(15): 4748-4755, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34231563

RESUMO

Since oxidative stress has been recognized as a major factor contributing to the progression of several neurodegenerative disorders, reactive oxygen species (ROS) including superoxide have received great attention as a representative molecular marker for the diagnosis of Alzheimer's disease (AD). Here, superoxide-sensitive fluorogenic molecular probes, benzenesulfonylated resorufin derivatives (BSRs), were newly devised for optical bioimaging of oxidative events in neurodegenerative processes. BSRs, fluorescence-quenched benzenesulfonylated derivatives of resorufin, were designed to recover their fluorescence upon exposure to superoxide through a selective nucleophilic uncaging reaction of the benzenesulfonyl cage. Among BSRs, BSR6 presented the best sensitivity and selectivity to superoxide likely due to the optimal reactivity matching between the nucleophilicity of superoxide and its electrophilicity ascribed to the highly electron-withdrawing pentafluoro-substitution on the benzenesulfonyl cage. Fluorescence imaging of inflammatory cells and animal models presented the potential of BSR6 for optical sensing of superoxide in vitro and in vivo. Furthermore, microglial cell (Bv2) imaging with BSR6 enabled the optical monitoring of intracellular oxidative events upon treatment with an oxidative stimulus (amyloid beta, Aß) or the byproduct of oxidative stress (4-hydroxynonenal, HNE).


Assuntos
Doença de Alzheimer , Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides/metabolismo , Animais , Sondas Moleculares , Estresse Oxidativo , Espécies Reativas de Oxigênio , Superóxidos
2.
Mitochondrial DNA B Resour ; 6(3): 860-861, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33796658

RESUMO

The complete chloroplast (cp) genome of Stauntonia hexaphylla, a monotypic genus native to Korea, was determined. The whole cp genome is 158,390 bp in size, containing a large single-copy (LSC) region of 87,115 bp and a small single-copy region (SSC) of 18,928 bp, separated by a pair of inverted repeats (IRs) of 26,174 bp. The cp genome encodes 117 genes, including 79 protein-coding, 38 tRNA-coding, and 8 rRNA-coding genes. The overall GC content is 37.8%. A phylogenetic analysis demonstrated a close relationship between S. hexaphylla and S. obovatifoliola subsp. urophylla. The cp genome will provide new insight into the evolution of Lardizabalaceae.

3.
Am J Chin Med ; 49(1): 69-94, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33371815

RESUMO

Vaccinium bracteatum Thunb. Leaves (VBL) are a component of traditional herbal medicines. However, molecular mechanisms of VBL in stress-related memory impairment are still unclear. This study aimed to investigate the spatial memory improvement effects of VBL in an animal model of chronic restraint stress (CRS) by using Y maze test and identified possible protective mechanisms against oxidative stress inducers (e.g., corticosterone and hydrogen peroxide [H2O2]) in SH-SY5Y neuronal cells. VBL showed neuroprotective effects via reduced release of lactate dehydrogenase (LDH) in corticosterone or H2O2-induced cell death that was mediated through the regulation of cleaved caspase-3 and Nrf2 pathways. Furthermore, CRS-exposed mice were orally administered VBL (10, 50, 100, and 200 mg/kg) daily for 21 days. CRS-exposed mice treated with VBL showed significantly increased spontaneous alternation in short-term memory (STM) and long-term memory (LTM) trials, and number of total arm entries in LTM trials as measured by the Y maze test. Moreover, VBL (50, 100, and 200 mg/kg) decreased acetylcholinesterase (AChE) activity in the hippocampus (HC, [Formula: see text] ¡ 0.01 and [Formula: see text] ¡ 0.001, respectively) and prefrontal cortex (PFC). CRS-exposed mice treated with VBL had dramatically decreased total Tau and Tau phosphorylation in the synapse of the HC and PFC which might be mediated by the regulation of CaMKII and GSK3[Formula: see text] phosphorylation. Additionally, VBL reduced CRS-induced upregulation of N-methyl-D-aspartate (NMDA) receptor subunits (NMDAR1, 2A, and 2B). Thus, VBL exerts spatial memory improvement by regulating CRS-induced NMDA receptor neurotoxicity and Tau hyperphosphorylation.


Assuntos
Transtornos da Memória/etiologia , Transtornos da Memória/psicologia , Memória/efeitos dos fármacos , Fitoterapia , Extratos Vegetais/farmacologia , Folhas de Planta/química , Receptores de N-Metil-D-Aspartato/metabolismo , Restrição Física/efeitos adversos , Aprendizagem Espacial/efeitos dos fármacos , Vaccinium myrtillus/química , Proteínas tau/metabolismo , Animais , Células Cultivadas , Doença Crônica , Humanos , Masculino , Transtornos da Memória/tratamento farmacológico , Transtornos da Memória/genética , Camundongos Endogâmicos C57BL , Fármacos Neuroprotetores , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/uso terapêutico , Estimulação Química
4.
Food Nutr Res ; 642020.
Artigo em Inglês | MEDLINE | ID: mdl-33240033

RESUMO

BACKGROUND: Climacterium is a series of physical and mental symptoms occurring in women and men due to decreased levels of sex hormones. Women lose the ability to become pregnant due to decreased ovarian estrogen production; the initial symptom being hot flushes. In addition, urogenital atrophy, sexual dysfunction, mood changes, and osteoporosis occur. Extracts of Stauntonia hexaphylla (SH) and Vaccinium bracteatum (VB) fruits, with a wide range of biological activities, are widely used in traditional herbal medicine. OBJECTIVE: The purpose of this study was to investigate the mitigation of menopausal symptoms, such as hot flushes and postmenopausal osteoporosis after combinatorial treatment with SH and VB (SHVB) of ovariectomized (OVX) rats. DESIGN: We measured the bone regenerative effect of SHVB on receptor activator of nuclear factor-κB (NF-κB) ligand-induced osteoclast differentiation in vitro and on ovariectomy-induced osteoporosis in vivo. We investigated the effect of SHVB in a rat model of menopausal hot flushes, in which the tail skin temperature increases following ovariectomy-induced rapid decline in estrogen levels. RESULTS: SHVB inhibited osteoclast formation and tartrate-resistant acid phosphatase activity in primary mouse bone marrow-derived cells. In an estrogen deficiency-induced rat model, measurement of serum bone turnover factors showed that treatment with SHVB lowered the increased bone turnover. Additionally, SHVB decreased OVX-induced bone loss of the total femur. SHVB inhibited osteoclast differentiation, prevented bone mass reduction, and improved trabecular bone structure and biochemical markers in OVX-induced osteoporosis. In addition, administration of SHVB significantly ameliorated the changes in skin temperature in OVX rats. CONCLUSION: SHVB improved the symptoms of menopause. These results provide the foundation for developing SHVB as a natural substance to replace hormones in the future.

5.
Mitochondrial DNA B Resour ; 5(3): 2490-2492, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-33457839

RESUMO

Elaeagnus is a genus which consists about 70 species of flowering plants in the family Elaeagnaceae, and its edible fruit is a natural product used as food and in traditional medicine. In this study, we sequenced the complete chloroplast (cp) genome of four species, namely Elaeagnus umbellate Thunb., E. multiflora Thunb., E. macrophylla Thunb., and E. glabra Thunb., to study their phylogenetic relationships within the Elaeagnaceae. Total lengths of the chloroplast genome were 152,261 bp, 152,267 bp, 152,224 bp, and 152,227 bp, respectively. The four genomes had representative quadripartite structures, with an LSC region (82,207 bp, 82,191 bp, 82,136 bp, and 82,139 bp) and an SSC region (18,262 bp, 18,282 bp,and 18,278 bp for both species) separated by a pair of IRs (25,896 bp, 25,897 bp, and 25,905 bp for the latter two species), respectively. Moreover, they were composed of 136-137 genes, including 88 protein-coding genes, 40-41 tRNA genes, and 8 rRNA genes. A maximum likelihood phylogenetic analysis indicated that E. umbellata was most closely related to E. multiflora, whereas E. macrophylla was close to E. glabra.

6.
Foods ; 8(12)2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31835363

RESUMO

Zanthoxylum schinifolium and Zanthoxylum piperitum are the sources of the well-known traditional Korean herbal medicines "sancho" (prickly ash) and "chopi" (Korean pepper), respectively. Sancho and chopi are often indiscriminately mixed due to the similar appearance of the herbal materials when used as spices and herbal medicines. Moreover, commercial sancho and chopi products often contain adulterants, which is insufficient to ensure food efficacy and safety. In this study, we developed hypervariable insertion/deletion (InDel) markers to distinguish between sancho and chopi products by comparing the complete chloroplast genome sequences of four Zanthoxylum species deposited in the National Center for Biotechnology Information (NCBI) GenBank. Comparative analyses of the nucleotide diversity (Pi) of these Zanthoxylum genomes revealed four hypervariable divergent sites (trnH-psbA, psbZ-trnG, trnfM-rps14, and trnF-ndhK) with Pi > 0.025 among 520 windows. Of these four regions, including two genic and two intergenic regions, only psbZ-trnG yielded accurate PCR amplification results between commercial sancho and chopi products from the Korean herbal medicine market. We therefore selected psbZ-trnG, an InDel-variable locus with high discriminatory powers, as a candidate DNA barcode locus. This InDel marker could be used as a valuable, simple, and efficient tool for identifying these medicinal herbs, thereby increasing the safety of these spices and herbal materials in the food market.

7.
Am J Chin Med ; : 1-20, 2018 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-30284467

RESUMO

The present study evaluates the anti-oxidative stress activity of Vaccinium bracteatum Thunb. fruit extract (VBFW) to identify the mechanisms responsible for its antidepressant-like effects. To evaluate the antidepressant and anti-oxidant effects of VBFW, malondialdehyde (MDA), serotonin transporter (SERT), and monoamine oxidase A (MAO-A) levels were measured in a mouse model of chronic restraint stress (CRS). The underlying mechanisms preventing oxidative stress and neuronal apoptosis were investigated using in vitro models of hydrogen peroxide (H2O[Formula: see text]-induced neuronal damage. The results showed that VBFW treatment (200[Formula: see text]mg/kg) significantly reduced MDA, SERT, and MAO-A levels in the prefrontal cortex of CRS mice. Furthermore, VBFW (30[Formula: see text][Formula: see text]g/mL) exhibited protective effects against H2O2-induced cell death via inhibition of the H2O2-induced increase in Bax and decrease in Bcl-2 levels within the mitochondria of SH-SY5Y cells. Furthermore, VBFW (10 and 30[Formula: see text][Formula: see text]g/mL) exerted protective effects against H2O2-induced cell death through inhibition of key mitochondria-associated apoptotic proteins such as cytochrome c, caspase-3 and PARP. Additionally, VBFW (10 and 30[Formula: see text][Formula: see text]g/mL) could improve the activity of anti-oxidant enzymes (such as SOD and catalase) in H2O2-treated SH-SY5Y cells. These results suggest that the antidepressant and anti-oxidant effects of VBFW might be mediated by the regulation of SERT and MAO-A, and possibly associated with regulation of oxidative stress-induced apoptosis.

8.
ACS Appl Mater Interfaces ; 10(45): 39107-39115, 2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30350940

RESUMO

To utilize the potential of small-molecule-based organic solar cells, proper designs of the photoactive materials which result in reasonable performance in a halogen-free solvent system and thickness tolerance over a range are required. One of the best approaches to achieve these requirements is via the molecular engineering of small-molecule electron donors. Here, we have modified a previously reported dithienobenzodithiophene (DTBDT)-based small molecule (SM1) via the dimerization approach, that is, the insertion of an additional DTBDT into the main backbone of the small molecule (SM2). An SM1-based photoactive film showed severe pinhole formation throughout the film when processed with a halogen-free o-xylene solvent. On the other hand, the modified small-molecule SM2 formed an excellent pinhole-free film when processed with the o-xylene solvent. Because of the dimerization of the DTBDT in the SM2 core, highly crystalline films with compact lamellae and an enhanced donor/acceptor interdigitation were formed, and all of these factors led to a high efficiency of 8.64% with chloroform and 8.37% with the o-xylene solvent systems. To the best of our knowledge, this study represents one of the best results with the SM donor and fullerene derivative acceptor materials that have shown the device performance with halogen-free solvents.

9.
Front Pharmacol ; 9: 604, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30038568

RESUMO

The leaves of Vaccinium bracteatum Thunb. are a source of traditional herbal medicines found in East Asia. The present study aimed to evaluate the mechanisms underlying the antidepressant-like effects of water extract of V. bracteatum Thunb. leaves (VBLW) in a mouse model of chronic restraint stress (CRS) and to identify the possible molecular in vitro mechanisms of the neuroprotective effects. The CRS-exposed mice were orally administered VBLW (100 and 200 mg/kg) daily for 21 days consecutively. The behavioral effects of VBLW were assessed through the forced swim test (FST) and the open field test (OFT). The levels of serum corticosterone (CORT), corticotropin releasing hormone (CRH), and adrenocorticotropin hormone (ACTH), brain monoamines, such as serotonin, dopamine, and norepinephrine, and serotonin turnover by tryptophan hydroxylase 2 (TPH2), serotonin reuptake (SERT), and monoamine oxidase A (MAO-A) were evaluated, in addition to the extracellular signal-regulated kinases (ERKs)/protein kinase B (Akt) signaling pathway. CRS-exposed mice treated with VBLW (100 and 200 mg/kg) showed significantly reduced immobility time and increased swimming and climbing times in the FST, and increased locomotor activity in the OFT. Moreover, CRS mice treated with VBLW exhibited significantly decreased CORT and ACTH, but enhanced brain monoamine neurotransmitters. In addition, CRS mice treated with VBLW had dramatically decreased protein levels of MAO-A and SERT, but increased TPH2 protein levels in the hippocampus and the PFC. Similarly, VBLW significantly upregulated the ERKs/Akt signaling pathway in the hippocampus and the PFC. Furthermore, VBLW showed neuroprotective effects via increased CREB phosphorylation in CORT-induced cell injury that were mediated through the ERK/Akt/mTOR signaling pathways. These results suggested that the antidepressant-like effects of VBLW might be mediated by the regulation of the HPA axis, glucocorticoids, and serotonin turnover, such as TPH2, SERT, and MAO-A, as well as the concentration of monoamine neurotransmitters, and the activities of ERK and Akt phosphorylation, which were possibly associated with neuroprotective effects.

10.
Molecules ; 23(6)2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29865213

RESUMO

The tuber of Cynanchum wilfordii (Baekshuoh Radix in Korean) is an important medicinal herb in Korea and China; however, it is difficult to differentiate C. wilfordii from a related medicinal herb, C. auriculatum (Baishouwu Radix in Chinese). We sought to develop a molecular method that could be used to distinguish between the tubers of C. wilfordii and C. auriculatum. We aligned the chloroplast genome sequences (available in the NCBI database) of the two species and identified three species-specific insertion and deletion (InDel) sites in the trnQ-psbK, rps2-rpoC2, and psaJ-rpl33 intergenic spacer (IGS) regions. To confirm the presence of these three InDels and validate their use as markers, we designed three primer pairs to amplify the trnQ-psbK, rps2-rpoC2, and psaJ-rpl33 IGS regions. Polymerase chain reaction (PCR) amplification of the trnQ-psbK IGS region yielded a 249 bp fragment for C. wilfordii, and 419 bp fragment for C. auriculatum, whereas the rps2-rpoC2 IGS primers produced a 629 bp fragment from C. wilfordii and a 282 bp fragment from C. auriculatum. In the psaJ-rpl33 IGS region, allele fragments of 342 and 360 bp in length were amplified from C. wilfordii, whereas 249 and 250 bp fragment were amplified from C. auriculatum. We propose these three InDel markers as a valuable, simple, and efficient tool for identifying these medicinal herbs and will thus reduce adulteration of these herbal materials in commercial markets.


Assuntos
Cynanchum/genética , DNA de Cloroplastos/genética , Marcadores Genéticos , Mutação INDEL , Primers do DNA , Reação em Cadeia da Polimerase
11.
J Am Chem Soc ; 140(21): 6700-6709, 2018 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-29767509

RESUMO

Proton transfer polymerization between thiol and epoxide groups is shown to be an adaptable and utilitarian method for the synthesis of hydrogels. For instance, the polymerization catalyst can be organic or inorganic, and the polymerization medium can be pure water, buffer solutions, or organic solvents. The gelation mechanism can be triggered at ambient conditions, at a physiological temperature of 37 °C, or through using light as an external stimulus. The ambient and photochemical methods both allow for nanoimprint lithography to produce freestanding patterned thick films. The required thiol- and epoxide-carrying precursors can be chosen from a long list of commercially available small molecular as well as polymeric materials. The water uptake, mechanical, and biodegradation properties of the gels can, therefore, be tuned through the choice of appropriate gelation precursors and polymerization conditions. Finally, the thio-ether groups of the cross-linked networks can be functionalized through a postgelation modification reaction to access sulfonium-based cationic structures. Such structural changes endow antibacterial properties to the networks. In their pristine form, however, the gels are biocompatible and nonadhesive, allowing cancer cells to grow in a cluster formation.

12.
Nutrients ; 9(10)2017 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-28953224

RESUMO

Benign prostatic hyperplasia (BPH) is characterized by uncontrolled proliferation of the prostate gland. Cynanchum wilfordii has been reported to improve sexual behavior in male rats. In this study, we investigated the protective effect of an aqueous extract of C. wilfordii (CWW) against BPH development in a testosterone-induced BPH rat model. The rats were divided into the following six groups: sham/vehicle; BPH/vehicle; BPH/finasteride; and three CWW doses (50, 100, and 200 mg/kg). After a 4-week treatment with CWW, the rats were euthanized at scheduled times, and their prostates were weighed, followed by a histopathological examination. Prostate growth inhibition rates in rats administered CWW 50, 100, and 200 mg/kg were 54.5%, 51.8%, and 50.1%, respectively. The BPH/CWW group showed decreased serum testosterone and dihydrotestosterone (DHT) levels compared to the BPH/vehicle group. Furthermore, the BPH/CWW group showed reduced prostate testosterone and DHT levels compared to the BPH/vehicle group. Mechanistically, the reverse transcription-polymerase chain reaction revealed downregulated mRNA expression levels of the androgen receptor, 5α-reductase, and B-cell lymphoma-2 (Bcl-2) in the BPH/CWW200 group compared with those in the testosterone-induced groups. In conclusion, these findings show the effectiveness of CWW in slowing the progression of testosterone-induced BPH in rats.


Assuntos
Inibidores de 5-alfa Redutase/farmacologia , Antagonistas de Receptores de Andrógenos/farmacologia , Proliferação de Células/efeitos dos fármacos , Colestenona 5 alfa-Redutase/metabolismo , Cynanchum , Extratos Vegetais/farmacologia , Próstata/efeitos dos fármacos , Hiperplasia Prostática/prevenção & controle , Receptores Androgênicos/efeitos dos fármacos , Testosterona , Inibidores de 5-alfa Redutase/isolamento & purificação , Antagonistas de Receptores de Andrógenos/isolamento & purificação , Animais , Colestenona 5 alfa-Redutase/genética , Cynanchum/química , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Masculino , Tamanho do Órgão , Extratos Vegetais/isolamento & purificação , Raízes de Plantas , Próstata/enzimologia , Próstata/patologia , Antígeno Prostático Específico/sangue , Hiperplasia Prostática/induzido quimicamente , Hiperplasia Prostática/enzimologia , Hiperplasia Prostática/patologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos Sprague-Dawley , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Fatores de Tempo
13.
Bioresour Technol ; 190: 466-73, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25804534

RESUMO

A microbial fuel cell (MFC) with biological Fe(III) reduction was implemented for simultaneous ethanolamine (ETA) degradation and electrical energy generation. In the feasibility experiment using acetate as a substrate in a single-chamber MFC with goethite and ammonium at a ratio of 3.0(mol/mol), up to 96.1% of the ammonium was removed through the novel process related to Fe(III). In addition, the highest voltage output (0.53V) and maximum power density (0.49Wm(-2)) were obtained. However, the ammonium removal and electrical performance decreased as acetate was replaced with ETA. In the long-term experiment, the electrical performance markedly decreased where the voltage loss increased due to Fe deposition on the membranes.


Assuntos
Compostos de Amônio/isolamento & purificação , Fontes de Energia Bioelétrica/microbiologia , Eletrodos/microbiologia , Etanolamina/metabolismo , Ferro/metabolismo , Purificação da Água/instrumentação , Compostos de Amônio/química , Desenho de Equipamento , Análise de Falha de Equipamento , Etanolamina/isolamento & purificação , Ferro/química , Oxirredução , Águas Residuárias , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/metabolismo
14.
Mycobiology ; 42(3): 296-300, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25346610

RESUMO

We selected Pleurotus ostreatus from among several edible mushrooms because it has high anti-gout xanthine oxidase (XOD) inhibitory activity. The maximal amount of XOD inhibitor was extracted when the Pleurotus ostreatus fruiting body was treated with distilled water at 40℃ for 48 hr. The XOD inhibitor thus obtained was purified by Sephadex G-50 gel permeation chromatography, ultrafiltration, C18 solid phase extraction chromatography and reverse-phase high-performance liquid chromatography with 3% of solid yield, and its XOD inhibitory activity was 0.9 mg/mL of IC50. The purified XOD inhibitor was a tripeptide with the amino acid sequence phenylalanine-cysteine-histidine and a molecular weight of 441.3 Da. The XOD inhibitor-containing ultrafiltrates from Pleurotus ostreatus demonstrated dose-dependent anti-gout effects in a Sprague-Dawley rat model of potassium oxonate-induced gout, as shown by decreased serum urated levels at doses of 500 and 1,000 mg/kg, although the effect was not as great as that achieved with the commercial anti-gout agent, allopurinol when administered at a dose of 50 mg/kg.

15.
Sci Total Environ ; 449: 443-50, 2013 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-23454706

RESUMO

Iron-based degradative solidification/stabilization (DS/S-Fe(II)) is a modification of conventional solidification/stabilization (S/S) that incorporates degradative processes for organic contaminant destruction with immobilization. This study investigated the effectiveness of a binder mixture of Portland cement and slag in a DS/S-Fe(II) system to treat trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), vinyl chloride (VC), trichloromethane (CF), and dichloromethane (MC), which are major chlorinated hydrocarbons contained in waste oils and waste organic solvents. For TCE, 1,1-DCE, and VC, degradation experiments were conducted using three different binder combinations with Fe(II) (cement/Fe(II), slag/Fe(II), and cement/slag/Fe(II)). When cement and slag were mixed at a 1:1 ratio (% wt), the TCE and 1,1-DCE dechlorination rate was enhanced compared to that when cement or slag was used alone with Fe(II). Also, batch experiments were conducted in the solid phase consisting of cement, slag, sand, and Fe(II) to treat liquid wastes that contain chlorinated compounds at high concentrations. TCE was completely removed after 5 days in the cement/slag/sand/Fe(II) system, in which the initial TCE concentration was 11.8mM, with Fe(II) concentration of 565 mM. While the CF concentration was decreased by 95% after 5 days when the initial CF and Fe(II) concentration was 0.25 mM and 200 mM, respectively. However, MC was not degraded with the cement/slag/Fe(II) system.

16.
J Hazard Mater ; 227-228: 402-9, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22695386

RESUMO

Monosulfate was examined as a novel material for As(V) removal since its layered double hydroxide structure was expected to possess a high capacity for anion exchange. Phase-pure monosulfate was synthesized by hydration at 80-90°C for 36 h using a stoichiometric mixture of tricalcium aluminate (calcined at 1300°C) and gypsum. The analyses of PXRD, WDXRF, and FE-SEM confirmed the successful synthesis of highly pure monosulfate with a negligible impurity of ettringite. Batch experiments were carried out to investigate the kinetics of As(V) removal by monosulfate. A close relationship between As(V) uptake and sulfate release was observed. The intercalation of arsenate in the interlayer of monosulfate was confirmed by PXRD and FT-IR analyses. From a series of equilibrium batch experiments, it is seen that initial sorption of As(V) on monosulfate follows Langmuir isotherm, whereas further injection of As(V) caused transformation of monosulfate to ettringite, which was confirmed by FE-SEM micrographs. However, after the transformation, the solid phases in the equilibrium experiments were found to significantly lose their ability to take up As(V) in exchange for sulfate. A possible explanation for this result was hypothesized and discussed in the context of the literature.


Assuntos
Arsênio/química , Sulfatos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Compostos de Alumínio/química , Compostos de Cálcio/química , Sulfato de Cálcio/química , Microscopia Eletrônica de Varredura , Difração de Pó , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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