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1.
Huan Jing Ke Xue ; 43(1): 387-397, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989523

RESUMO

Heavy metal ion wastewater poses a serious threat to human health and the environment. The adsorption method is an important method to remove heavy metal ions from heavy metal wastewater. Magnetic attapulgite (ATP) composite nanomaterials with excellent adsorption properties were prepared by grafting the Fe3O4 nanoparticles and using 3-aminopropyl triethoxy silane (APTES) modification. The prepared ATP-Fe3O4-APTES materials were used as adsorbents and applied to the treatment of heavy metal ion wastewater. The structure and surface properties of the materials were characterized by FT-IR, XRD, SEM, TEM, and BET characterization, Zeta potential, and VSM. The effects of pH, adsorption time, adsorption temperature, and initial concentration of Pb2+ on the adsorption properties of the ATP-Fe3O4-PEI materials were investigated. The results show that the maximum adsorption capacity of the materials for Pb2+ was 129.32 mg·g-1 under optimum conditions. The adsorption process conformed to the pseudo second order kinetic model and Langmuir adsorption isotherm, which indicates that the adsorption of Pb2+ is a monolayer chemical adsorption and a spontaneous endothermic process. The driving force of adsorption mainly comes from the coordination between the amino group (-NH2) on the ATP-Fe3O4-APTES surface and Pb2+. These results indicate that the functionalized magnetic attapulgite adsorbent has good adsorption properties for heavy metal ions and is expected to be used in the treatment of heavy metal ion wastewater.


Assuntos
Vermelho Congo , Poluentes Químicos da Água , Adsorção , Humanos , Cinética , Compostos de Magnésio , Compostos de Silício , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
2.
AAPS PharmSciTech ; 23(1): 48, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34984564

RESUMO

Gefitinib is a tyrosine kinase inhibitor that is intended for oral administration yet suffers poor bioavailability along with undesirable side effects. To enhance its solubility and allow colon targeting, gefitinib (ZD) and blends of different ratios of polymers (ternary dispersion) were prepared in organic solution, and solid dispersions were generated employing the spray drying (SD) technique. The methylmethacrylate polymer Eudragit S 100 was incorporated for colon targeting; polyvinylpyrrolidone (PVP) and hydroxypropyl methyl cellulose (HPMC) were utilised to improve the solubility of ZD. SEM, DSC, XRPD, FT-IR, dissolution and cytotoxicity studies were undertaken to characterise and evaluate the developed formulations. SEM images revealed that the rod-shaped crystals of ZD were transformed into collapsed spheres with smaller particle size in the spray-dried particles. DSC, FTIR and XRPD studies showed that ZD loaded in the spray-dried dispersions was amorphous. ZD dissolution and release studies revealed that while a significant (P < 0.05) increase in the ZD dissolution and release was observed from HPMC-based solid dispersion at pH 7.2 (up to 95% in 15 h), practically no drug was released at pH 1.2 and pH 6.5. Furthermore, the HPMC-based solid dispersions displayed enhanced mucoadhesive properties compared with PVP-based ones. Interestingly, cell viability studies using the neutral red assay showed that PVP and HPMC-based solid dispersions had no additional inhibitory effect on Caco-2 cell line compared to the pure drug.


Assuntos
Secagem por Atomização , Células CACO-2 , Liberação Controlada de Fármacos , Gefitinibe , Humanos , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier
3.
Se Pu ; 40(1): 88-99, 2022 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-34985220

RESUMO

Submicron nonporous silica (NPS) materials feature small particle sizes, smooth surfaces, and regular shapes. They also exhibit excellent performance as a stationary phase; however, their use is limited by their low specific surface area and low phase ratio. Therefore, a novel surface modification strategy tailored for NPS microspheres was designed, involving a multi-step reaction. 3-Glycidyloxypropyltrimethoxysilane (GPTS) was first grafted onto NPS particles as a silane coupling agent. Polyethyleneimine (PEI), a high-molecular-weight polymer, was then coated onto the particles, providing numerous amino reaction sites. In the final step, an acylation reaction was initiated between stearoyl chloride and the amino groups to obtain the final product, designated as C18-NH2-GPTS-SiO2. Elemental analysis, FT-IR spectroscopy, Zeta potential analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were employed to investigate the success of the chemical modifications at each step. The carbon content increased from 0.55% to higher than 8.29%. Thus, it solved the low carbon loading capacity problem when modifying NPS microspheres with traditional C18 reversed phase (e. g., octadecyl chlorosilane modification). Meanwhile, the reasons for the considerable differences between NPS and porous silica (PS) microspheres in terms of the reactivity to surface modification were investigated in detail. The BET method was employed to compare the pore structures. FT-IR and 29Si solid-state NMR spectroscopy were employed to analyze the differences in the structure and quantity of silanol groups on the surfaces of the NPS and PS microspheres. Differences were observed not only in the pore size and surface area, but also in the types of silanol groups. FT-IR analysis indicated that the NPS and PS microspheres had different υSi-OH band positions, which shifted from 955 to 975 cm-1, respectively. 29Si solid-state NMR analysis further highlighted the differences in structural information for Si atom environments. Results revealed that 16% of silicon atoms in the PS microspheres had one hydroxyl group (isolated silanols, Q3, δ 100), while 19% had two hydroxyl groups (geminal silanols, Q2, δ 90). On the other hand, the NPS microspheres possessed no geminal silanols, and only 30% of the Si atoms were in the Q3 state. Therefore, the NPS microspheres had a lower density of silanol groups and lacked geminal silanol groups, compared to the PS microspheres. Geminal silanol groups have already been confirmed in previous studies to offer far higher reactivity than isolated silanols. These factors together explained the low reactivity of NPS microspheres toward surface modification. Further, the low specific surface area of the microspheres arising from their nonporous nature made it challenging to obtain a high carbon content through a simple one-step reaction. Hydrophobic substances such as hydrocarbons from the benzene series and polycyclic aromatic hydrocarbons (PAHs) were selected to study the chromatographic performance. The hydrophobic mechanism was revealed by the separation of PAHs using different ratios of acetonitrile. Separation was achieved with a C18-NH2-GPTS-SiO2 column, following which a hydrophobic phenomenon occurred. The presence of the amino coating led to the inversion of the electroosmotic flow (EOF) of the silica microspheres on the pressurized capillary electrochromatography (pCEC) platform. It also enhanced the linear velocity in the pCEC platform when the pH was selected to be low. The effects of the applied voltage on the separation ability of the 720 nm C18-NH2-GPTS-SiO2 column were examined to determine optimal conditions. Rapid and effective separation was achieved in a relatively short time. Therefore, the C18-NH2-GPTS-SiO2 stationary phase is promising for practical use with a higher phase ratio, demonstrating superiority for use in reversed-phase pCEC separation, and thus, providing a new strategy and valuable reference for the future application of submicron NPS microspheres.


Assuntos
Eletrocromatografia Capilar , Carbono , Tamanho da Partícula , Dióxido de Silício , Espectroscopia de Infravermelho com Transformada de Fourier
4.
In Vivo ; 36(1): 189-197, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34972714

RESUMO

BACKGROUND/AIM: The pathogenesis, treatment and prevention of atherosclerosis continue to be the subject of intensive research and study by the scientific community. Based on Fourier-transform infrared spectra and 3D-Doppler echogram, we attempted to develop a computational simulation model for predicting the association of atherosclerotic risk factors with pathogenic molecular structural changes. MATERIALS AND METHODS: Atheromatic carotid arteries from 56 patients (60-85 years old) were used as samples. Color 3D-Doppler echogram screening was performed on all patients preoperatively. Each infrared spectrum consisted of 120 co-added spectra at a spectral resolution of 4 cm-1 Results: The infrared spectral analysis reveals 'marker bands', such as the 1,744 cm-1 band assigned to aldehyde formation and to the 'fingerprint' digital spectral region of 1,050-1,169 cm-1, characteristic of the presence of advanced glycation end products (C-O-C). The accumulation of calcium phosphate salts increases the formation rate of stenosis. The critical point of stenosis risk starts at about 45%, while when stenosis is over 60-70%, the risk of ischemic stroke or other major adverse cardiovascular events increases dramatically. CONCLUSION: Fourier-transform infrared spectroscopy and mathematical simulation models showed that carotid artery stenosis over 45% reduces the blood flow rate, while stenosis over 65% dramatically increases the hemodynamic disturbance, with a parallel increase the rate of ischemic stroke or other major adverse cardiovascular events.


Assuntos
Aterosclerose , Doenças das Artérias Carótidas , Estenose das Carótidas , Acidente Vascular Cerebral , Idoso , Idoso de 80 Anos ou mais , Aterosclerose/diagnóstico por imagem , Artérias Carótidas/diagnóstico por imagem , Doenças das Artérias Carótidas/diagnóstico por imagem , Estenose das Carótidas/diagnóstico por imagem , Humanos , Pessoa de Meia-Idade , Espectroscopia de Infravermelho com Transformada de Fourier
5.
Food Chem ; 371: 131385, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34808778

RESUMO

The combination of multiple dietary polyphenols may have synergistic beneficial effects. And the beneficial effects can be further improved by the encapsulation of proteins. The interactions of procyanidin B2 (PB2) and/or dihydromyricetin (DMY) with ß-lactoglobulin (ß-LG) were investigated using multi-spectroscopic techniques and molecular docking. The structural change of ß-LG in the presence of PB2 and/or DMY was demonstrated by dynamic light scattering, Fourier transform infrared spectroscopy and circular dichroism spectroscopy. Response surface analysis was used to optimize the synergistic antioxidant activity between PB2 and DMY. Besides, the antioxidant activity, stability, in vitro digestion and cytotoxicity of PB2 and DMY in the binary and ternary systems were investigated. These studies will elucidate the interaction mechanism of PB2 and/or DMY with ß-LG. The research results can provide theoretical support for the development of functional foods and beverages with synergistic activity, improved stability and bioaccessibility, thereby promoting human health and preventing diseases.


Assuntos
Lactoglobulinas , Polifenóis , Antioxidantes , Digestão , Humanos , Simulação de Acoplamento Molecular , Espectroscopia de Infravermelho com Transformada de Fourier
6.
J Environ Manage ; 302(Pt B): 114103, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798586

RESUMO

In this study, (3-mercaptopropyl) triethoxysilane (MPTMS)-modified ordered mesoporous silica (OMS) materials were prepared using a post-grifting method, with MPTMS as the organic functionalized reagent. The OMS materials were analyzed by FT-IR spectra, N2 sorption, and small angle X-ray scattering to evaluate their potential for scavenging Cd2+ from water. Moreover, a (3-mercaptopropyl) triethoxysilane-functionalized ordered mesoporous silica modified polyvinylidene fluoride (MPTMS-OMS/PVDF) membrane was synthesized using the solvent phase inversion method to remediate wastewater containing heavy metal ions. The MPTMS-OMS was characterized by a maximum specific surface area of 422 m2/g, high surface hydrophilicity, and high pure water flux. The MPTMS-OMS/PVDF exhibited a dynamic adsorption capacity for Cd2+ in water. At an MPTMS-OMS content of 5 wt%, the Cd2+ removal efficiency was 90%, whereas the pure PVDF showed no Cd2+ adsorption capacity. These results highlight the potential of the MPTMS-OMS/PVDF membrane to eliminate Cd2+ during the decontamination of aqueous streams containing low-concentrations of contaminants.


Assuntos
Metais Pesados , Dióxido de Silício , Adsorção , Cádmio , Polímeros de Fluorcarboneto , Polivinil , Espectroscopia de Infravermelho com Transformada de Fourier , Água
7.
J Environ Manage ; 302(Pt B): 114111, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34800771

RESUMO

In this study, the visible-light-induced intimately coupled photocatalysis and biodegradation (ICPB) technology was fabricated using the TiO2/bagasse cellulose composite as the carrier and Phanerochaete mixed activated sludge as the biological source. The ICPB degradation effect of elemental chlorine free (ECF) bleaching wastewater was evaluated via the response surface design. Then, the wastewater was characterized, including absorbable organic halogen (AOX), dissolved organic carbon (DOC), chemical oxygen demand (COD), chroma, pH, suspended solids, and the organic compound changes in wastewater were analyzed by fourier transform infrared spectroscopy (FT-IR). Under the optimal conditions of pH 7, carrier filling rate of 5%, aeration rate of 2 L/min, and reaction time of 7 h, the degradation efficiencies of AOX, COD, and DOC were 95%, 91%, and 82%, respectively. The X-ray photoelectron spectroscopy (XPS) results of the ICPB carrier after the reaction were almost identical to those before the reaction. The biomass and its activity on the ICPB system were analyzed by the dominant bacteria during degradation (Curaneotrichosporon, Paenibacillus, Cellulonas, Phanerochaete, Dechlorobacter, Rhodotorula, Sphingobacterium, and Ruminiclostridium), which had a good degradation effect on wastewater. This study affords a novel method for the degradation of ECF bleaching wastewater and a new idea for ICPB technology optimization.


Assuntos
Águas Residuárias , Biodegradação Ambiental , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio
8.
Food Chem ; 366: 130530, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34303204

RESUMO

In this study, the effects of different temperatures, incubation times and types of reducing sugars, including glucose and different low molecular weight (Mw) chito-oligosaccharides (COS) with varying acetylation degree (AD), on the extent of Maillard reaction (MR) on chitosan-based films were studied. Interestingly, an improvement of structural and functional properties of all MR-crosslinked films was noted, which is more pronounced by heating at higher temperature and exposure time. These findings were proved through Fourier-transform infrared and X-ray diffraction analyses. In addition, color change and Ultraviolet spectra demonstrate that glucose addition provides the high extent of MR, followed by COS1 (Mw < 4.4 kDa; AD, 18.20%) and COS2 (Mw < 4.4 kDa; AD, 10.63%). These results were confirmed by enhanced water resistance and thermal properties. Moreover, MR-chitosan/COS films showed the highest mechanical properties, whereas, glucose-loaded films were brittle, as demonstrated by scanning electron microscopy micrographs. Furthermore, MR-chitosan/COS1 films exhibited the better antioxidant behavior followed by chitosan/glucose and chitosan/COS2 films, mainly at higher heating-conditions. Thereby, MR-crosslinked chitosan/COS based films were attractive to be applied as functional and active coating-materials in various fields.


Assuntos
Quitosana , Antioxidantes , Glucose , Reação de Maillard , Peso Molecular , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Chemosphere ; 286(Pt 1): 131478, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34303904

RESUMO

Due to the widespread usage of hydrogen peroxide (H2O2) in various consumer and industrial products (Examples: fuel cells and antibacterial agents), it became important to accurately detect H2O2 concentration in environmental, medical and food samples. Herein, titanium carbide Ti3C2Tx (MXene) was synthesized by using Ti, Al and C powders at high-temperature. Then, nanocrystalline iron oxide (α-Fe2O3) was obtained from a single solid-phase method. Using Ti3C2Tx and Fe2O3 powders, Ti3C2Tx-Fe2O3 nanocomposite was prepared by ultrasonication. As-synthesized, Ti3C2Tx-Fe2O3 composite had been characterized by UV-Visible (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Raman spectroscopy. The Fe2O3 nanoparticles (NPs) were decorated on the surface of Ti3C2Tx as observed by high resolution scanning electron microscopy (HR-SEM) and high resolution transmission electron microscopy (HR-TEM). The Ti3C2Tx nanosheets were formed with the average size of 400-500 nm. HR-SEM images of α-Fe2O3 showed that the coral-like particles with the average length ~5 µm were obtained. The electrochemical properties of the individual (Ti3C2Tx and α-Fe2O3) and composite materials (Ti3C2Tx-Fe2O3) were investigated by cyclic voltammetry (CV). Ti3C2Tx-Fe2O3 nanocomposite modified electrode had exhibited potent electro-catalytic activity for H2O2 reduction by reducing the overpotential about 320 mV and a linear response was recorded from 10 nM to 1 µM H2O2. The optimization of various parameters such as material composition ratio, amount of catalyst, effects of pH, scan rate and interference effects with other biomolecules were carried out. In addition, the kinetic parameters such as rate constant, diffusion coefficient and the active surface area of the electrodes were calculated. Moreover, the Ti3C2Tx-Fe2O3 composite modified electrode was used successfully to detect H2O2 in food and urine samples. We believe that Ti3C2Tx-Fe2O3 composite based materials could be used for the fabrication of non-enzymatic H2O2 sensors for medical diagnosis, food safety and environmental monitoring applications.


Assuntos
Peróxido de Hidrogênio , Titânio , Compostos Férricos , Espectroscopia de Infravermelho com Transformada de Fourier
10.
J Hazard Mater ; 421: 126629, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34315020

RESUMO

Spent caustic discharges are responsible for increasing oil and grease (O&G) matter in refineries wastewater, leading to increasing treatment costs due to low water quality and environmental constraints associated with high O&G concentration discharges. As a way to settle and optimize treatment technologies for such complex effluents, more insight regarding the effluents impact and deeper characterization is necessary. The present study intends to assess the possibility of a relationship between the processed crude oils with the polar O&G concentration in naphthenic spent caustic as well as in the final wastewater; Sines refinery was considered as case-study. Also, in order to get insights about the nature of the polar O&G compounds, their structures and their prevalence in the effluent treatment system was carried out through detailed analytical characterization studies. Proton nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) were chosen. It was found that, for the Sines refinery, spent caustic discharges may increase the refinery effluent management cost up to 3 €/ton of processed crude oil, every time a high kerosene cut acid crude oil is processed. It was also found that the typical spent caustic O&G effluents are composed by organic contaminants with low molecular weight (MW), with aromatic and polar arrangements, like phenolic groups and naphthenic acids. This outcome is crucial for subsequently establishing the best technologies able to deal with such complex effluents.


Assuntos
Cáusticos , Petróleo , Petróleo/análise , Petróleo/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias
11.
Food Chem ; 366: 130645, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34325243

RESUMO

The chemical and thermal characteristics of goldenberry pomace oil (GPO) and goldenberry seed oil (GSO) were investigated. GPO and GSO contained high levels of unsaturated fatty acids (90.1% and 85.1%, respectively), and the major fatty acid was linoleic (62.0% and 72.8%, respectively). Additionally, GPO contained eleven triacylglycerol (TAG) species, three of which represented 82.7%, namely C54:6, C54:4 and C52:4, and trilinolein was the dominant one (35.5%). GSO contained nine TAG species, two of which represented 80.3%, namely C54:6 and C52:4, and trilinolein was dominant (53.3%). The DSC analysis of GPO and GSO revealed that three exothermal peaks were detected during cooling. Three endothermal peaks (one of which is exothermal for GSO) were detected during melting, and the most significant peaks occurred at low temperatures. FTIR spectra indicated that GPO and GSO did not contain peroxides or trans fatty acids, but they did contain low concentrations of free fatty acids.


Assuntos
Physalis , Cristalização , Ácidos Graxos , Sementes , Espectroscopia de Infravermelho com Transformada de Fourier
12.
Biochim Biophys Acta Biomembr ; 1864(1): 183779, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34560046

RESUMO

Biophysical characterization of antimicrobial peptides helps to understand the mechanistic aspects of their action. The physical behavior of the KR-12 antimicrobial peptide (e.g. orientation and changes in secondary structure), was analyzed after interactions with a Staphylococcus aureus membrane model and solid surfaces. We performed antimicrobial tests using Gram-positive S. aureus (ATCC 25923) bacteria. Moreover, Langmuir-Blodgett experiments showed that the synthetic peptide can disturb the lipidic membrane at a concentration lower than the Minimum Inhibitory Concentration, thus confirming that KR-12/lipid interactions are involved. Partially- and fully-deactivated KR-12 hybrid samples were obtained by physisorption and covalent immobilization in chitosan/silica and glyoxal-rich solid supports. The correlation of Langmuir-Blodgett data with the α-helix formation, followed by FTIR-ATR in a frozen-like state, and the antimicrobial activity showed the importance of these interactions and conformation changes on the first step action mode of this peptide. This is the first time that material science (immobilization in solid surfaces assisted by FTIR-ATR analysis in frozen-like state) and physical (Langmuir-Blodgett/Schaefer) approaches are combined for exploring mechanistic aspects of the primary action mode of the KR-12 antimicrobial peptide against S. aureus.


Assuntos
Antibacterianos/química , Catelicidinas/química , Lipídeos/antagonistas & inibidores , Fragmentos de Peptídeos/química , Antibacterianos/farmacologia , Catelicidinas/farmacologia , Quitosana/química , Quitosana/farmacologia , Humanos , Lipídeos/química , Lipídeos de Membrana/antagonistas & inibidores , Testes de Sensibilidade Microbiana , Fragmentos de Peptídeos/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade
13.
Opt Lett ; 47(1): 102-105, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34951890

RESUMO

By stabilizing the evaporation dynamics of a microliter fluorocarbon droplet, we demonstrate a fast-scan optofluidic Fourier transform (FT) spectrometer on the tip of an optical fiber operating in the 1000-2000 nm window with a resolution of 3.5 cm-1 (i.e., <1 nm at 1560 nm). Compared with other FT near-infrared (NIR) small-scale spectrometers reported in the literature, the fluorocarbon droplet spectrometer shows the largest wavelength span and span/resolution ratio, allowing spectral analysis of broadband or narrowband radiation to be easily performed. Our results open the way for the practical application of droplet spectrometers as advanced optofluidic NIR analyzers with small size and low cost that are capable of operating in harsh environments, even in the absence of electrical power sources.


Assuntos
Refratometria , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Biochim Biophys Acta Mol Basis Dis ; 1868(1): 166279, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34600082

RESUMO

The tumor stroma plays a pivotal role in colon cancer genesis and progression. It was observed that collagen fibers in the extracellular matrix (ECM) of cancer stroma, undergo a strong remodeling. These fibrous proteins result more aligned and compact than in physiological conditions, creating a microenvironment that favors cancer development. In this work, micro-FTIR spectroscopy was applied to investigate the chemical modifications in the tumor stroma. Using Fuzzy C-means clustering, mean spectra from diseased and normal stroma were compared and collagen was found to be responsible for the main differences between them. Specifically, the modified absorptions at 1203, 1238, 1284 cm-1 and 1338 cm-1 wavenumbers, were related to the amide III band and CH2 bending of side chains. These signals are sensitive to the interactions between the α-chains in the triple helices of collagen structure. This provided robust chemical evidence that in cancer ECM, collagen fibers are more parallelized, stiff and ordered than in normal tissue. Principal Component Analysis (PCA) applied to the spectra from malignant and normal stroma confirmed these findings. Using LDA (Linear Discriminant Analysis) classification, the absorptions 1203, 1238, 1284 and 1338 cm-1 were examined as spectral biomarkers, obtaining quite promising results. The use of a PCA-LDA prediction model on samples with moderate tumor degree further showed that the stroma chemical modifications are more indicative of malignancy compared to the epithelium. These preliminary findings have shown that micro-FTIR spectroscopy, focused on collagen signals, could become a promising tool for colon cancer diagnosis.


Assuntos
Carcinogênese/genética , Carcinoma/diagnóstico , Colágeno/química , Neoplasias do Colo/diagnóstico , Espectroscopia de Infravermelho com Transformada de Fourier , Carcinoma/química , Carcinoma/patologia , Colágeno/ultraestrutura , Colo/química , Colo/patologia , Neoplasias do Colo/química , Neoplasias do Colo/patologia , Epitélio/química , Epitélio/patologia , Matriz Extracelular/química , Matriz Extracelular/patologia , Humanos , Análise de Componente Principal , Microambiente Tumoral/genética
15.
Chemosphere ; 287(Pt 3): 132342, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34583298

RESUMO

Organosilane, with functional organic groups attached to inorganic silicon atoms, exhibits excellent passivation performance for pyrite. However, a considerable number of micro-cracks will gradually appear on the surface of passivation film under long-term corrosion of oxidizing medium, resulting in a significant decrease of passivation effect. To improve the stability and long-term performance of organosilane coating, a novel passivator (PT-ATP@HQ) with self-healing function was prepared to inhibit the oxidation of pyrite. We chose 3-mercaptopropyltrimethoxysilane (Prop-SH) and tetraethoxysilane (TEOS) as the host coating (PT), and attapulgite clay (ATP) loaded with 8-hydroxyquinoline (8-HQ) was used to endow the coating with better passivation and self-healing performance. The electrochemical and chemical leaching results showed that the addition of ATP@HQ greatly improved the passivation performance of PT coating. The passivation efficiencies of total Fe and SO42- reached to 88.1% and 79.2%, respectively. We also found that the protective capability of the scratched PT-ATP@HQ coating can be recovered automatically through 8-HQ release from ATP. The passivation and self-healing mechanisms were investigated by FT-IR, XPS, 29Si NMR, and other characterization methods, which were as follows: firstly, the organosilanes hydrolyzed to form highly active silanol groups, then dehydration condensation reaction occurred between silanol molecules and ATP@HQ to obtain cross-linked network structure connected by Si-O-Si bonds. After that, Si-OH groups reacted with the hydroxyl groups of pyrite to form Fe-O-Si bonds, thereby an inert and dense passivation film attached to the surface of pyrite. Once the passivation film is locally damaged, 8-HQ will automatically release to repair the cracks.


Assuntos
Compostos de Organossilício , Argila , Ferro , Compostos de Magnésio , Oxirredução , Compostos de Silício , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfetos
16.
Chemosphere ; 287(Pt 4): 132370, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34592209

RESUMO

The aim of this study is to produce an electrode that can be used in H2O2 production and Electro-Fenton (EF) process by an effective, cheap, and easy method. For this reason, a superhydrophobic electrode with a higher PTFE ratio and high thickness was produced with a simple press. The produced electrode was used in the production of H2O2 and mineralization of Atrazine. First, the effect of pH, cathode voltage, and operation time on H2O2 production was evaluated. The maximum H2O2 concentration (409 mg/L), the highest current efficiency (99.80%), and the lowest electrical energy consumption (3.16 kWh/kg) were obtained at 0.8 V, 7.0 of pH, and 120 min, and the stability of the electrode was evaluated up to 720 min. Then, the effects of the operational conditions (pH, cathode voltage, operating time, and catalyst concentration) in electro-Fenton were evaluated. The fastest degradation of Atrazine (>99%) was obtained at 2.0 V, 3.0 of pH, and 0.3 mM of Fe2+ in 15 min. In the final part of the study, the degradation intermediates were identified, and the characterization of the electrode was evaluated by SEM, XRD, FT-IR, tensiometer, potentiostat, and elemental analyzer.


Assuntos
Atrazina , Poluentes Químicos da Água , Carbono , Eletrodos , Peróxido de Hidrogênio , Oxirredução , Oxigênio , Fuligem , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
17.
Chemosphere ; 287(Pt 4): 132351, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34592215

RESUMO

Sulfate radical advance oxidation processes (SR-AOPs) have attracted a greater attention as a suitable alternative of the hydroxyl radical based advance oxidation process (HR-AOPs). In this study, for the first time we report liquid phase mineralization of nuclear grade cationic IRN-77 resin in Co2+/peroxymonosulfate (PMS) based SR-AOPs. After the dissolution of cationic IRN-77 resin, 30 volatile and 15 semi-volatile organic compounds were analyzed/detected using non-targeted GC-MS analysis. The optimal reaction parameters for the highest chemical oxygen demand (COD) removal (%) of IRN-77 resin were determined, and the initial pH, PMS dosage, and reaction temperature were found to be the most influential parameters for the resin degradation. We successfully achieved ∼90% COD removal (1000 mg/L; 1000 ppm) of dissolved spent resin for SR-AOPs by optimizing the reaction parameters as initial pH = 9, Co2+ = 4 mM (catalyst), PMS = 60 mM (as oxidant) at 60 °C temperature for 60 min reaction. The electron spin resonance spectroscopy (ESR) spectra confirmed the presence of SO4∙- and OH∙ as main reactive species in the Co2+/PMS resin system. In addition, Fourier transform infrared spectroscopy (FT-IR) analyses were used for structural characterization of solid and liquid phase resin samples. We believe that this work will offer a robust approach for the effective treatment of spent resin generated from nuclear industry.


Assuntos
Resinas de Troca Iônica , Peróxidos , Oxirredução , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfatos
18.
Chemosphere ; 287(Pt 4): 132385, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34597635

RESUMO

Discharging of inorganic and organic pollutants creates a serious threat to the human health and the environment. In the current work, we have synthesized Ethylenediaminetetraacetic acid (EDTA) functionalized graphene oxide-chitosan nanocomposite (GO-EDTA-CS) for simultaneous removal of inorganic (i.e., mercury (Hg(II) and copper (Cu(II)) and organic pollutants (i.e., methylene blue (MB) and crystal violet (CV)) from wastewater via adsorption process. The structural, functional, morphological, elemental compositions, surface area and thermal properties of the synthesized nanocomposite were identified using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), Brunauer-Emmett-Teller (BET), and thermogravimetric analyzer (TGA), respectively. Different batch adsorption experiments such as pH effect, contact time, initial pollutants concentration, reusability etc. were studied in monocomponent system to optimize the results. The adsorption process apparently followed pseudo-second-order (PSO) kinetics for both pollutants, however the adsorption kinetics was also explained by the intra-particle diffusion model. The isotherm data for both metals ions and dyes were well fit by the Langmuir isotherm model. The maximum adsorption capacities of the adsorbent were determined 324 ± 3.30 130 ± 2.80, 141 ± 6.60, and 121 ± 3.50 mg g-1 for Hg(II), Cu(II), MB, and CV, respectively. The excellent adsorption capacity was attributed to the availability of various active functional groups (e.g., -COOH, -OH, -NH2, etc.) on the adsorbent. The EDS, elemental mapping and FTIR analysis performed before and after the adsorption of heavy metals and dyes by GO-EDTA-CS confirmed the simultaneous adsorption of the pollutants. Moreover, GO-EDTA-CS could maintain its adsorption capacity for both inorganic and organic pollutants even after seven cycles of adsorption-desorption, indicating itself a promising adsorbent for practical wastewater treatment containing both inorganic and organic toxic pollutants.


Assuntos
Quitosana , Poluentes Ambientais , Nanocompostos , Poluentes Químicos da Água , Adsorção , Ácido Edético , Grafite , Humanos , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias , Poluentes Químicos da Água/análise
19.
J Colloid Interface Sci ; 607(Pt 2): 1762-1775, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34600340

RESUMO

Excess fluoride in water poses a threat to ecology and human health, which has attracted global attention. In this study, a series of lanthanum-based metal-organic frameworks (La-MOFs) were synthesized by varying the organic ligands (i.e., terephthalic acid (BDC), trimesic acid (BTC), biphenyl-4,4-dicarboxylic acid (BPDC), 2,5-dihydroxyterephthalic acid (BHTA), and 1,2,4,5-benzenetetracarboxylic acid (PMA)) to control the microscopic structure of the MOFs and subsequently apply them for the removal of fluoride in water. The maximum capture capacities of La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC at 298 K are 105.2, 125.9, 145.5, 158.9, and 171.7 mg g-1, respectively. The adsorption capacity is greater than most reported adsorbents. The adsorption isotherms of La-MOFs for fluoride are well fit to the Langmuir isotherm model. In addition, the adsorption kinetics of La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC follows the pseudo-second-order kinetic model, and the kinetic rate-limiting step of adsorption is chemical adsorption. Thermodynamics revealed that temperature is favorable for the adsorption of fluoride. Meanwhile, La-BTC, La-BPDC, La-BHTA, La-PMA, and La-BDC are suitable for the removal of fluoride in a relatively wide pH range (4.0-9.0). Simultaneously, from X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis, electrostatic attraction and ligand exchange are identified as the main action mechanisms for the adsorption of fluoride of La-MOFs. The prepared La-MOFs are used as efficient adsorbents for removal of fluoride in actual water, indicating that they have great potential in removing fluoride in real and complex environmental water. This work provides a new strategy for designing adsorbents with adjustable microstructure and expected function to effectively recover fluorosis in water.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Adsorção , Fluoretos , Humanos , Concentração de Íons de Hidrogênio , Cinética , Lantânio , Ligantes , Espectroscopia de Infravermelho com Transformada de Fourier , Água , Poluentes Químicos da Água/análise
20.
Chemosphere ; 287(Pt 4): 132286, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34600349

RESUMO

Coal is primarily a fuel material but lately it has been utilized as an adsorbent for removing toxic metal ions. However, its usage for removing organic pollutants is not well studied. We report here a systematic study on the use of coal samples of varying carbon contents as adsorbents for removing Basic Blue 41 as a model cationic dye. The coal samples were collected from coal mines and were thoroughly characterized. The concentrations of carbon, hydrogen, oxygen, nitrogen and sulphur contents were measured by CHNS analyzer. The concentrations of aluminum, silicon, sulphur, titanium and iron were determined by EDXRF, which corresponded to silicon dioxide (quartz) and aluminium silicate (kaolinite) as the major mineral inclusions, corroborated by XRD results and micrographs showing elemental maps determined from SEM-EDAX. The coal samples with low carbon content revealed higher adsorption capacity (qe âˆ¼ 8.0-9.3 mg/g) of Basic Blue dye at optimized adsorbent dose (2 mg/mL), pH 9 and contact time (120 min). The adsorption kinetic studies satisfied pseudo second order model and the intra-particle diffusion of the dye was evident. The dye adsorption followed Langmuir adsorption isotherm, and the qmax values ranged between 17 and 30 mg/g for low carbon content coal. The FT-IR, Brunauer-Emmett-Teller (BET) surface area and zeta potential results of the coal samples could explain the adsorption phenomenon of cationic dye. The kinetic and thermodynamic studies revealed that the adsorption of Basic Blue 41 dye was based on chemisorptions mechanism.


Assuntos
Carvão Mineral , Poluentes Químicos da Água , Adsorção , Carbono , Concentração de Íons de Hidrogênio , Cinética , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Poluentes Químicos da Água/análise
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