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1.
Water Sci Technol ; 81(10): 2092-2108, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32701489

RESUMO

Mesocellular foam (MCF) silica molecular sieve material was successfully synthesized using a hydrothermal method. X-ray diffraction, infrared spectroscopy, low nitrogen adsorption-desorption, scanning electron microscopy, and transmission electron microscopy (TEM) characterization techniques were used to characterize the material. Low temperature nitrogen adsorption-desorption method showed that pore size of the synthesized MCF was 12 nm. TEM study showed that the synthesized MCFs had honeycomb structure pores, which can be good for the absorbance of dye organic macromolecule substances. This work studied the adsorption of crystal violet by MCF and the results showed that when the adsorptive conditions were pH = 9.0, MCF:crystal violet = 150:1, and when the contact time was 10 min at room temperature of 25 ± 1 °C, the adsorption rate reached 99.71% and adsorption capacity was 6.646 mg/g. This study found that the adsorption is a Freundlich type, it is a multimolecular layer adsorption, and it belongs to the pseudo-second-order kinetic model. According to the ΔG0 obtained from adsorption thermodynamics, when the temperature is 25-40 °C, the adsorption enthalpy change ΔH0 = -25.65 kJ/mol, ΔG0 < 0, the adsorption is an exothermic reaction and can spontaneously occur. The adsorption entropy change ΔS0 = 5.54 J/(mol·K) and the entropy of system increased.


Assuntos
Violeta Genciana , Dióxido de Silício , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Temperatura , Termodinâmica
2.
Environ Sci Pollut Res Int ; 27(20): 25727-25739, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32350844

RESUMO

The Ocotea puberula bark powder (OPBP) was evaluated as an effective adsorbent for the removal of crystal violet (CV) from colored effluents. OPBP was characterized and presented a surface with large cavities, organized as a honeycomb. The main functional groups of OPBP were O-H, N-H, C=O, and C-O-C. The adsorption of CV on OPBP was favorable at pH 9 with a dosage of 0.75 g L-1. The Avrami model was the most suitable to represent the adsorption kinetic profile, being the estimated equilibrium concentration value of 3.37 mg L-1 for an initial concentration of 50 mg L-1 (CV removal of 93.3%). The equilibrium was reached within 90 min. The data were better described by the Langmuir isotherm, reaching a maximum adsorption capacity of 444.34 mg g-1 at 328 K. The Gibbs free energy ranged from - 26.3554 to - 27.8055 kJ mol-1, and the enthalpy variation was - 11.1519 kJ mol-1. The external mass transfer was the rate-limiting step, with Biot numbers ranging from 0.0011 to 0.25. Lastly, OPBP application for the treatment of two different simulated effluents was effective, achieving a removal percentage of 90%.


Assuntos
Ocotea , Poluentes Químicos da Água/análise , Adsorção , Violeta Genciana , Concentração de Íons de Hidrogênio , Cinética , Casca de Planta/química , Termodinâmica
3.
J Mol Diagn ; 22(6): 729-735, 2020 06.
Artigo em Inglês | MEDLINE | ID: covidwho-477970

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic now has >2,000,000 confirmed cases worldwide. COVID-19 is currently diagnosed using quantitative RT-PCR methods, but the capacity of quantitative RT-PCR methods is limited by their requirement of high-level facilities and instruments. We developed and evaluated reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays to detect genomic RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus of COVID-19. RT-LAMP assays reported in this study can detect as low as 100 copies of SARS-CoV-2 RNA. Cross-reactivity of RT-LAMP assays to other human coronaviruses was not observed. A colorimetric detection method was adapted for this RT-LAMP assay to enable higher throughput.


Assuntos
Betacoronavirus/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Colorimetria/métodos , Primers do DNA , Violeta Genciana , RNA Viral/genética , Transcrição Reversa
4.
J Mol Diagn ; 22(6): 729-735, 2020 06.
Artigo em Inglês | MEDLINE | ID: covidwho-214148

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic now has >2,000,000 confirmed cases worldwide. COVID-19 is currently diagnosed using quantitative RT-PCR methods, but the capacity of quantitative RT-PCR methods is limited by their requirement of high-level facilities and instruments. We developed and evaluated reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays to detect genomic RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus of COVID-19. RT-LAMP assays reported in this study can detect as low as 100 copies of SARS-CoV-2 RNA. Cross-reactivity of RT-LAMP assays to other human coronaviruses was not observed. A colorimetric detection method was adapted for this RT-LAMP assay to enable higher throughput.


Assuntos
Betacoronavirus/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Colorimetria/métodos , Primers do DNA , Violeta Genciana , RNA Viral/genética , Transcrição Reversa
5.
J Mol Diagn ; 22(6): 729-735, 2020 06.
Artigo em Inglês | MEDLINE | ID: covidwho-35118

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic now has >2,000,000 confirmed cases worldwide. COVID-19 is currently diagnosed using quantitative RT-PCR methods, but the capacity of quantitative RT-PCR methods is limited by their requirement of high-level facilities and instruments. We developed and evaluated reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays to detect genomic RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus of COVID-19. RT-LAMP assays reported in this study can detect as low as 100 copies of SARS-CoV-2 RNA. Cross-reactivity of RT-LAMP assays to other human coronaviruses was not observed. A colorimetric detection method was adapted for this RT-LAMP assay to enable higher throughput.


Assuntos
Betacoronavirus/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Colorimetria/métodos , Primers do DNA , Violeta Genciana , RNA Viral/genética , Transcrição Reversa
6.
J Mol Diagn ; 22(6): 729-735, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32276051

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic now has >2,000,000 confirmed cases worldwide. COVID-19 is currently diagnosed using quantitative RT-PCR methods, but the capacity of quantitative RT-PCR methods is limited by their requirement of high-level facilities and instruments. We developed and evaluated reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays to detect genomic RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus of COVID-19. RT-LAMP assays reported in this study can detect as low as 100 copies of SARS-CoV-2 RNA. Cross-reactivity of RT-LAMP assays to other human coronaviruses was not observed. A colorimetric detection method was adapted for this RT-LAMP assay to enable higher throughput.


Assuntos
Betacoronavirus/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Colorimetria/métodos , Primers do DNA , Violeta Genciana , RNA Viral/genética , Transcrição Reversa
7.
Environ Monit Assess ; 192(5): 262, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32246207

RESUMO

In this research, an efficient sorbent based on poly(ß-cyclodextrin-ester)-functionalized silica-coated magnetic nanoparticles (MNPs-CDP) was prepared and used for magnetic solid-phase extraction of the malachite green (MG) and crystal violet (CV) from water samples prior to their determination by high-performance liquid chromatography-ultra violet detection (HPLC-UV). The synthesized nanoparticles were characterized by the field emission-scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FT-IR). Of course, the factors, which could influence the extraction efficiency like pH, sorbent amount, salt content, extraction time, desorption time, eluent type, and volume and sample volume, were optimized by response surface methodology. Then, for both of MG and CV, good linearity (0.1-200 µg L-1, r2 ≥ 0.99) was achieved under the optimized conditions. The limits of detection (LODs) and the limits of quantification (LOQs), for both of MG and CV, were 0.03 µg L-1 and 0.1 µg L-1, respectively. Precision of the method expressed as the relative standard deviations (RSDs) at concentration level of 100 µg L-1 was 5.6 and 4.2 for MG and CV, respectively. Ultimately, usability of proposed method was investigated by analysis of CV and MG in tap water, fish pond water, and the lake water, and the satisfactory recoveries were obtained in the range of 92-100.5%.


Assuntos
Violeta Genciana/química , Nanopartículas de Magnetita , Corantes de Rosanilina/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/química , Adsorção , Monitoramento Ambiental , Limite de Detecção , Fenômenos Magnéticos , Dióxido de Silício , Espectroscopia de Infravermelho com Transformada de Fourier , beta-Ciclodextrinas
8.
Chemosphere ; 254: 126752, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32335436

RESUMO

In the literature, there is a lack of data on the effect of gentian violet (GV) and congo red (CR) dyes on the biosynthesis pathway of biogenic amines (BAs) in Lemna minor L. (common duckweed). This plant species is an important link in the food chain. Both dyes inhibited growth, biomass yield and the biosynthesis of chlorophyll a in common duckweed. The predicted toxic units demonstrated that GV had a more toxic effect on the growth rate and biomass yield of common duckweed than CR. Decarboxylase activity in the biosynthesis of BAs in common duckweed is also a useful indicator for evaluating the toxicity of both dyes. Gentian violet also exerted more phytotoxic effects on the analyzed biochemical features of common duckweed because it changed the putrescine (Put) biosynthesis pathway, increased tyramine content 1.6 fold, inhibited the activity of S-adenosylmethionine decarboxylase by 40% and the activity of ornithine decarboxylase (ODC) by 80%. Tyrosine decarboxylase (TDC) was most active in plants exposed to the highest concentration of GV. Similarly to control plants, in common duckweed exposed to CR, Put was synthesized from ornithine; however, spermidine content was 86% higher, Put content was 51% lower, and ODC activity was 86% lower.


Assuntos
Araceae/fisiologia , Vermelho Congo/toxicidade , Violeta Genciana/toxicidade , Poluentes Químicos da Água/toxicidade , Araceae/efeitos dos fármacos , Aminas Biogênicas , Biomassa , Vias Biossintéticas , Clorofila A , Violeta Genciana/metabolismo
9.
Nat Commun ; 11(1): 1207, 2020 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-32139700

RESUMO

The emergence of antibiotic resistant bacteria is a major threat to the practice of modern medicine. Photobactericidal agents have obtained significant attention as promising candidates to kill bacteria, and they have been extensively studied. However, to obtain photobactericidal activity, an intense white light source or UV-activation is usually required. Here we report a photobactericidal polymer containing crystal violet (CV) and thiolated gold nanocluster ([Au25(Cys)18]) activated at a low flux levels of white light. It was shown that the polymer encapsulated with CV do not have photobactericidal activity under white light illumination of an average 312 lux. However, encapsulation of [Au25(Cys)18] and CV into the polymer activates potent photobactericidal activity. The study of the photobactericidal mechanism shows that additional encapsulation of [Au25(Cys)18] into the CV treated polymer promotes redox reactions through generation of alternative electron transfer pathways, while it reduces photochemical reaction type-ІІ pathways resulting in promotion of hydrogen peroxide (H2O2) production.


Assuntos
Escherichia coli/efeitos dos fármacos , Escherichia coli/efeitos da radiação , Ouro/farmacologia , Luz , Nanopartículas/química , Compostos de Sulfidrila/química , Violeta Genciana/farmacologia , Testes de Sensibilidade Microbiana , Espectroscopia Fotoeletrônica , Espécies Reativas de Oxigênio/metabolismo
10.
Dermatol Online J ; 26(1)2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32155035

RESUMO

Pyoderma gangrenosum is a rare autoinflammatory skin disease. Treatment is multifactorial, addressing inflammation, pain, underlying disease, if present, and the wound. Gentian violet has been used for hundreds of years in a variety of dermatologic conditions for its anti-inflammatory properties. This study aims to evaluate gentian violet in wound healing for pyoderma gangrenosum. We conducted a retrospective chart review of patients with pyoderma gangrenosum treated with gentian violet at the Wake Forest School of Medicine Department of Dermatology in the last 10 years. The primary outcome was clinical improvement. Of the 34 cases that met inclusion criteria, 70% improved with gentian violet, 24% had no documented change, 3% initially improved then worsened, and 3% had unclear results. Gentian violet is a safe and cheap treatment that may improve resolution of pyoderma gangrenosum lesions in addition to systemic therapy.


Assuntos
Anti-Infecciosos Locais/administração & dosagem , Violeta Genciana/administração & dosagem , Pioderma Gangrenoso/tratamento farmacológico , Administração Tópica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
13.
BMC Infect Dis ; 20(1): 170, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32087681

RESUMO

BACKGROUND: Infectious meningitis is a serious disease and patient outcome relies on fast and reliable diagnostics. A syndromic panel testing approach like the FilmArray ME can accelerate diagnosis and therefore decrease the time to pathogen specific therapy. Yet, its clinical utility is controversial, mainly because of a remaining uncertainty in correct interpretation of results, limited data on its performance on clinical specimens and its relatively high costs. The aim of this study was to analyze clinical performance of the assay in a real life setting at a tertiary university hospital using a pragmatic and simple sample selection strategy to reduce the overall cost burden. METHODS: Over a period of 18 months we received 4623 CSF samples (2338 hospitalizations, 1601 individuals). FilmArray ME analysis was restricted to CSF-samples with a high pretest probability of infectious meningitis, e.g. positive Gram-stain, samples in which leukocytes and/or bacteria were evident or urgent suspicion of infection was communicated by clinicians. N = 171 samples matched to our risk criteria and were subjected to FilmArray ME analysis. Those samples were also analyzed by reference methods: culture only (n = 45), PCR only (n = 20) or both methods (n = 106). RESULTS: 56/171 (32.75%) were FilmArray ME positive. Bacterial pathogens were detected in 30/56 (53.57%), viral pathogens were detected in 27/56 (48.21%) and yeast DNA was detected in 1/56 (1.79%) of positive samples. Double detection occurred in 2/56 samples. In 52/56 (92.86%) FilmArray ME positive samples, results could be confirmed by the reference assays (sensitivity = 96.30%, specificity =96.58%). CONCLUSION: The FilmArray ME assay is a fast and reliable diagnostic tool for the management of infectious meningitis and can easily be implemented in routine diagnostic workflows. However, correlation of test results and underlying clinical symptoms requires experienced users and the awareness of potentially false negative or false positive results. Moreover, considering the need for antimicrobial susceptibility testing, the use of molecular tests as a stand-alone diagnostic cannot be recommended.


Assuntos
Testes Diagnósticos de Rotina/métodos , Encefalite/diagnóstico , Meningite/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase Multiplex/métodos , Coloração e Rotulagem/métodos , Testes Diagnósticos de Rotina/economia , Encefalite/líquido cefalorraquidiano , Encefalite/microbiologia , Encefalite/virologia , Violeta Genciana , Alemanha , Hospitais Universitários , Humanos , Laboratórios , Meningite/líquido cefalorraquidiano , Meningite/microbiologia , Meningite/virologia , Técnicas de Diagnóstico Molecular/economia , Reação em Cadeia da Polimerase Multiplex/economia , Fenazinas , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Coloração e Rotulagem/economia , Centros de Atenção Terciária
14.
Environ Sci Pollut Res Int ; 27(11): 12047-12054, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31983007

RESUMO

Preparation of Ce2(MoO4)3 nanoparticles is reported via the microemulsion method by using two different surfactants, i.e., cationic surfactant, cetyltrimethylammonium bromide (CTAB), and nonionic surfactant, Triton X-100. The water pools produced in the microemulsion systems behave as nanoreactors for reaction of the cerium (3+) and molybdate ions to produce Ce2(MoO4)3 nanoparticles. The structure and morphology of the products were characterized by using Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray analysis (EDX), UV-Vis spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The prepared Ce2(MoO4)3 nanoparticles were successfully utilized as photocatalysts to remove crystal violet from aqueous solution in which the maximum percentage of dye degradation was about 89% after 5 h under the visible light irradiation. Also, kinetic study of the photocatalytic degradation revealed that pseudo-second order model is the best one for describing kinetic of the reaction.


Assuntos
Violeta Genciana , Nanopartículas , Catálise , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
15.
BMC Res Notes ; 13(1): 29, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31931859

RESUMO

OBJECTIVE: Bacterial meningitis is a life threatening condition that requires prompt recognition and treatment. Currently, Gram stain is widely used for the microscopic detection of bacterial pathogens in cerebrospinal fluid (CSF). In Nepal, fluorescent microscopes have been installed in laboratories as a part of the National tuberculosis control program. However, information on the utility of the acridine orange (AO) stain for the direct detection of bacteria in CSF samples in Nepal is not available. Therefore, this study aims to compare Gram stain and AO stain for the rapid detection of bacterial pathogens in CSF of clinically suspected meningitis cases in Kathmandu, Nepal. RESULTS: Bacterial pathogens were detected in 9.30% (36/387) by either of the three tests, 9.04% (35/387) by AO stain, 8.27% (32/387) by culture and 6.46% (25/387) by Gram's stain. Considering culture as a gold standard, the sensitivity of AO stain was higher than Gram stain. The specificity of AO stain was 98.87%. Detection and differentiation of the bacteria was much clear in AO staining than Gram staining. AO is a better alternative to Gram stain in the rapid detection of bacterial pathogens in CSF in the setting where fluorescent microscope is available.


Assuntos
Laranja de Acridina , Bactérias/isolamento & purificação , Líquido Cefalorraquidiano/microbiologia , Corantes Fluorescentes , Meningites Bacterianas/diagnóstico , Microscopia de Fluorescência , Laranja de Acridina/química , Bactérias/patogenicidade , Corantes , Corantes Fluorescentes/química , Violeta Genciana/química , Meningites Bacterianas/microbiologia , Microscopia , Nepal , Fenazinas/química , Sensibilidade e Especificidade , Coloração e Rotulagem
16.
PLoS Negl Trop Dis ; 14(1): e0007481, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31961864

RESUMO

BACKGROUND: Crystal violet (CV) was used for several years in blood banks to eliminate the parasite Trypanosoma cruzi in endemic areas in order to prevent transfusion-transmitted Chagas disease. One mechanism of action described for CV involves inhibition of proline uptake. In T. cruzi, proline is essential for host cell infection and intracellular differentiation among other processes, and can be obtained through the proline permease TcAAAP069. METHODOLOGY/PRINCIPAL FINDINGS: CV inhibited proline transporter TcAAAP069 and parasites overexpressing this permease were 47-fold more sensitive to this compound than control parasites. Using CV as reference molecule, loratadine, cyproheptadine, olanzapine and clofazimine were identified as structurally related compounds to CV (structural analogues) by in silico drug repurposing through a similarity-based virtual screening protocol. All these already-approved drugs for clinical use inhibited TcAAAP069 activity with different efficacies and also presented trypanocidal action in epimastigotes, trypomastigotes and amastigotes of the Y, CL Brener and Dm28c T. cruzi strains. Finally, a synergistic effect between benznidazole and the CV chemical analogues was evidenced by combination and dose-reduction indexes values in epimastigotes and trypomastigotes of the Y strain. CONCLUSIONS/SIGNIFICANCE: Loratadine, cyproheptadine and clofazimine inhibit TcAAAP069 proline transporter and also present trypanocidal effect against all T. cruzi life stages in strains from three different DTUs. These CV structural analogues could be a starting point to design therapeutic alternatives to treat Chagas disease by finding new indications for old drugs. This approach, called drug repurposing is a recommended strategy by the World Health Organization to treat neglected diseases, like Chagas disease, and combination therapy may improve the possibility of success of repositioned drugs.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/antagonistas & inibidores , Violeta Genciana/química , Violeta Genciana/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Doença de Chagas/parasitologia , Clofazimina/farmacologia , Simulação por Computador , Reposicionamento de Medicamentos , Humanos , Estágios do Ciclo de Vida/efeitos dos fármacos , Loratadina/farmacologia , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Tripanossomicidas/química , Trypanosoma cruzi/genética , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/metabolismo
17.
Environ Sci Pollut Res Int ; 27(10): 10484-10494, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31940142

RESUMO

Sugarcane bagasse, a largely available waste worldwide, was submitted to solid-state fermentation (SSF) using the fungus Metarhizium anisopliae, aiming to produce enzymes. The solid waste generated from SSF was tested as an alternative biosorbent to treat colored effluents containing crystal violet (CV) dye. The biosorbent, here named BW (bagasse waste), was characterized, and experimental tests were performed to verify the influence of pH and dosage on the CV biosorption. Isotherms and biosorption kinetics were performed, and the biosorption thermodynamic parameters were determined. The potential of BW was also evaluated for the treatment of a simulated textile effluent. The maximum biosorption capacity was 131.2 mg g-1 at 328 K, and the Liu was the most appropriate model to represent equilibrium data. The biosorption was spontaneous and endothermic. The use of BW in the simulated effluent showed that it is an efficient material, reaching color removal values of 85%. Therefore, the sugarcane bagasse generated from SSF can be considered a potential biosorbent to remove CV from textile effluents. This finding is relevant from the total environment viewpoint, since, at the same time, SSF generates enzymes and a solid waste, which in turn can be used as biosorbent to treat colored effluents.


Assuntos
Violeta Genciana , Poluentes Químicos da Água/análise , Adsorção , Biomassa , Corantes , Concentração de Íons de Hidrogênio , Cinética , Resíduos Sólidos , Termodinâmica
18.
Environ Sci Pollut Res Int ; 27(9): 9152-9166, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31916156

RESUMO

A novel adsorbent derived from banyan aerial roots was prepared via modification and employed to aqueous gentian violet (GV) and rhodamine B (RhB) removal. The surface morphology and physicochemical properties of modified banyan aerial roots (MBARs) were investigated by SEM, EDS, N2 adsorption/desorption, zeta potential, XRD, and FT-IR characterization experiments. Adsorption factors were tested, and the optimal conditions for GV and RhB removal were pH of 6 and 3, doses of 0.02 g and 0.03 g, and reaction time of 540 min. Adsorption isotherm simulation illustrated that theoretical monolayer adsorption capacities of GV and RhB were 456.64 mg/g and 115.23 mg/g, respectively. Kinetics data was assessed with pseudo-first-order and pseudo-second-order models, and the latter described GV and RhB adsorption better at 288 K, 298 K, 308 K, and 318 K. Thermodynamic analysis indicated that GV and RhB adsorption processes were endothermic and spontaneous. From the research results, it could be inferred that GV adsorption was mainly dominated by electrostatic interaction, while RhB adsorption might be primarily attributed to electrostatic interaction and hydrogen bonding. The study based on full utilization of waste plant fibers facilitates recycling of biomass resources, and due to simplicity, safety, and eco-friendliness of the preparation, as well as low cost and high efficiency of the application, MBARs may be potential absorbents for the treatment of dyestuff wastewater.


Assuntos
Rodaminas/química , Poluentes Químicos da Água , Purificação da Água , Adsorção , Violeta Genciana , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
19.
Sci Total Environ ; 711: 134662, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31831251

RESUMO

A novel Fe3O4-graphene-biochar composite (GBC-Fe3O4) was prepared to enhance the adsorption capacity and recollection efficiency of graphene-biochar composites (GBCs). The adsorption characteristics were tested to remove crystal violet (CV), which is a refractory compound in industrial wastewater. Structural and morphological analysis exhibited that a larger surface area, greater thermal stability, and more functional groups were present after Fe3O4 nanoparticles coated the GBC surface. This improved the CV adsorption versus uncoated GBC. The introduction of G and Fe3O4 nanoparticles collectively reduced the zeta potentials of GBC-Fe3O4 to -38.1 ± 1.1 mV versus -24.3 ± 2.2 mV for GBC and -20.7 ± 1.2 mV for BC. The maximum Qmax values were obtained 436.68 mg/g at 40 °C. Fourier transform infrared analysis suggested that the interactions of functional groups, such as aromatic C = C and C = O, -OH, C-C, and π-π played an important role in CV adsorption. The thermodynamic analysis of Langmuir and Freundlich isotherms indicated that the adsorption improved as a spontaneous endothermic process. The saturation magnetization of GBC-Fe3O4 reached 61.48 emu/g, allowing efficient recollection of the material with a magnet. The CV adsorbability of the re-collected GBC-Fe3O4 was 157.31 mg/g, which was slightly lower than freshly prepared GBC-Fe3O4 (199 mg/g). These findings demonstrated that GBC-Fe3O4 was an efficient and reusable multifunctional biochar.


Assuntos
Carvão Vegetal , Adsorção , Compostos Férricos , Violeta Genciana , Grafite , Cinética , Poluentes Químicos da Água
20.
J Forensic Sci ; 65(2): 661-663, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31617942

RESUMO

Ink dating is a significant problem in terms of forensic science. Ballpoint pens are generally used as writing tools on the documents. Aging is determination of the changes in dyes and solvents in the composition of ink over time by analytical methods. The evaporation of the solvents from the paper surface is faster than the decomposition process of the dyes. In this study, in 2017, we were asked by the court to determine whether the texts on the suspicious pages of an agenda dated 1996 were written within 2 years or earlier. Phenoxyethanol and dyes were examined in the composition of all suspected ink samples. The results show the determination of both the decomposition process of the dyes and the evaporation process of phenoxyethanol in the aging of the document entries written by ballpoint pen.


Assuntos
Corantes , Etilenoglicóis , Ciências Forenses/métodos , Violeta Genciana , Tinta , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Fatores de Tempo
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