RESUMO
Daytime HONO photolysis is an important source of atmospheric hydroxyl radicals (OH). Knowledge of HONO formation chemistry under typical haze conditions, however, is still limited. In the Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain in 2018, we investigated the wintertime HONO formation and its atmospheric implications at a rural site Gucheng. Three different episodes based on atmospheric aerosol loading levels were classified: clean periods (CPs), moderately polluted periods (MPPs) and severely polluted periods (SPPs). Correlation analysis revealed that HONO formation via heterogeneous conversion of NO2 was more efficient on aerosol surfaces than on ground, highlighting the important role of aerosols in promoting HONO formation. Daytime HONO budget analysis indicated a large missing source (with an average production rate of 0.66 ± 0.26, 0.97 ± 0.47 and 1.45 ± 0.55 ppbV/hr for CPs, MPPs and SPPs, respectively), which strongly correlated with photo-enhanced reactions (NO2 heterogeneous reaction and particulate nitrate photolysis). Average OH formation derived from HONO photolysis reached up to (0.92 ± 0.71), (1.75 ± 1.26) and (1.82 ± 1.47) ppbV/hr in CPs, MPPs and SPPs respectively, much higher than that from O3 photolysis (i.e., (0.004 ± 0.004), (0.006 ± 0.007) and (0.0035 ± 0.0034) ppbV/hr). Such high OH production rates could markedly regulate the atmospheric oxidation capacity and hence promote the formation of secondary aerosols and pollutants.
Assuntos
Poluentes Ambientais , Ácido Nitroso , Ácido Nitroso/análise , Poluentes Ambientais/análise , Dióxido de Nitrogênio/análise , China , Aerossóis/análiseRESUMO
Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in the North China Plain. The Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain (McFAN) investigated the physicochemical mechanisms leading to haze formation with a focus on the contributions of multiphase processes in aerosols and fogs. We integrated observations on multiple platforms with regional and box model simulations to identify and characterize the key oxidation processes producing sulfate, nitrate and secondary organic aerosols. An outdoor twin-chamber system was deployed to conduct kinetic experiments under real atmospheric conditions in comparison to literature kinetic data from laboratory studies. The experiments were spanning multiple years since 2017 and an intensive field campaign was performed in the winter of 2018. The location of the site minimizes fast transition between clean and polluted air masses, and regimes representative for the North China Plain were observed at the measurement location in Gucheng near Beijing. The consecutive multi-year experiments document recent trends of PM2.5 pollution and corresponding changes of aerosol physical and chemical properties, enabling in-depth investigations of established and newly proposed chemical mechanisms of haze formation. This study is mainly focusing on the data obtained from the winter campaign 2018. To investigate multiphase chemistry, the results are presented and discussed by means of three characteristic cases: low humidity, high humidity and fog. We find a strong relative humidity dependence of aerosol chemical compositions, suggesting an important role of multiphase chemistry. Compared with the low humidity period, both PM1 and PM2.5 show higher mass fraction of secondary inorganic aerosols (SIA, mainly as nitrate, sulfate and ammonium) and secondary organic aerosols (SOA) during high humidity and fog episodes. The changes in aerosol composition further influence aerosol physical properties, e.g., with higher aerosol hygroscopicity parameter κ and single scattering albedo SSA under high humidity and fog cases. The campaign-averaged aerosol pH is 5.1 ± 0.9, of which the variation is mainly driven by the aerosol water content (AWC) concentrations. Overall, the McFAN experiment provides new evidence of the key role of multiphase reactions in regulating aerosol chemical composition and physical properties in polluted regions.
RESUMO
Hypochlorite (ClO-) is an important reactive oxygen species (ROS) in organisms. In this work, a fluorescent probe DBTM based on triphenylamine was synthesized successfully and characterized by spectral methods. The designed probe can rapidly respond to ClO- in just 1 min, followed by the apparent color change from red to yellow. The colorimetric and ratiometric absorbance change of DBTM was attributed to the strong oxidation of ClO-, which broke the connected double bonds and destroyed the conjugate system. The probe DBTM showed an excellent selectivity towards ClO- in comparison with other ROS probes. Besides, the DBTM probe exhibited a highly sensitive response to ClO-, with the detection limits calculated to be 3.3 nM. The probe can be applied in the form of cotton swabs and test strips that could detect ClO- easily, suggesting its potential use as imaging agents for realistic ClO- detection. In particular, DBTM exhibited very low background fluorescence in living cells and was able to detect the minor variation of endogenous hypochlorite in L929 cells. Based on these advantages, the probe DBTM could be a good candidate for detecting ClO- in biological systems.
Assuntos
Compostos de Anilina/química , Corantes Fluorescentes/química , Ácido Hipocloroso/análise , Animais , Ânions/análise , Linhagem Celular , Camundongos , Microscopia de Fluorescência/métodos , Modelos Moleculares , Imagem Óptica/métodos , Espectrometria de Fluorescência/métodosRESUMO
Two simple and novel fluorescent probes (CDC1 and CDC2) have been designed and prepared here for sensing HSO3- with large Stokes shifts (about 250 nm). The synthesized probes can react with HSO3- just in 2 min, followed by the obvious color change from blue to colorless. The colorimetric and ratiometric absorbance response of the probes to HSO3- is due to the addition of HSO3- to the electron-deficient C=C double bond group, which prevents significant intramolecular charge transfer (ICT). Besides, CDC1 and CDC2 can detect HSO3- in pure water and detection limits of CDC1 and CDC2 reached 4.59 nM and 8.19 nM, respectively. Considering the delicate difference in the two prepared probes' molecular structures, CDC1 containing the carboxyl group has a more significant fluorescence intensity change response to HSO3- in pure water than CDC2 (with sulfinyl group). Beyond better response characteristics, CDC1 also has lower cytotoxicity and better biocompatibility compared with CDC2, which could be chosen to detect HSO3- in living cells. With these superior properties, probe CDC1 could have a potential application in the fields of environmental and biological detection.
Assuntos
Acroleína/análogos & derivados , Corantes Fluorescentes/química , Sulfitos/química , Água/química , Acroleína/química , Animais , Linhagem Celular Tumoral , Humanos , Limite de Detecção , Camundongos , Espectrofotometria UltravioletaRESUMO
Hydrogel adsorbents have attracted considerable attention due to their sludge minimization, good water permeability and renewable performance. Here, a promising strategy for the one-step preparation of pullulan/polydopamine hybird hydrogels (PPGels) was presented. Dumbbell-shaped cross-linker neopentyl glycol diglycidyl ether (NGDE, 2 arms) and Y-shaped cross-linker trimethylolpropane triglycidyl ether (TTE, 3 arms) were selected to study the relationship between cross-linker structure and hydrogel performances. The NGDE possessing less molecular repulsive force and higher reactivity demonstrated more effective cross-linking with the pullulan, which leaded to a decrease in pore size of the hydrogel. Meanwhile, the introduction of polydopamine significantly enhanced the adsorption ability and gave the resulting hybrid gel the specific selectivity toward cationic dyes (96 mg/g for crystal violet, 25.8 mg/g for methylene blue and barely not adsorption for azophloxine). Our data suggested that the electrostatic interaction played a vital role in the dye adsorption process, and the adsorption data could be explained by pseudo-second-order model and Langmuir isotherm model. Furthermore, the obtained PPGel could be easily separated after adsorption. This study describes the relationship between cross-linker structure and properties of pullulan/polydopamine hybrid gels, which provides a new strategy to create polysaccharide-based adsorbents for wastewater remediation.
Assuntos
Corantes , Poluentes Químicos da Água , Adsorção , Glucanos , Hidrogéis , Indóis , Polímeros , Purificação da ÁguaRESUMO
An easy hydrothermal synthesis strategy was applied to synthesize green-yellow emitting nitrogen-doped carbon dots (N-CDs) using 1,2-diaminobenzene as the carbon source, and dicyandiamide as the dopant. The nitrogen-doped CDs resulted in improvement in the electronic characteristics and surface chemical activities. N-CDs exhibited bright fluorescence emission and could response to Ag+ selectively and sensitively. Other ions produced nearly no interference. A N-CDs based fluorescent probe was then applied to sensitively determine Ag+ with a detection limit of 5 × 10-8 mol/L. The method was applied to the determination of Ag+ dissolved in water. Finally, negligibly cytotoxic, excellently biocompatibile, and highly fluorescent carbon dots were applied for HepG2 cell imaging and the quenched fluorescence by adding Ag+ , which indicated its potential applications.
Assuntos
Carbono/química , Corantes Fluorescentes/química , Nitrogênio/química , Pontos Quânticos , Prata/análise , Carbono/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fluorescência , Corantes Fluorescentes/farmacologia , Guanidinas/química , Células Hep G2 , Humanos , Estrutura Molecular , Tamanho da Partícula , Fenilenodiaminas/química , Relação Estrutura-Atividade , Água/químicaRESUMO
Stimuli-responsive polymeric hydrogels are promising and appealing delivery vehicles for protein/peptide drugs and have made protein/peptide delivery with both dosage- and spatiotemporal-controlled manners possible. Here a series of new Salecan-based pH-sensitive hydrogels were fabricated for controlled insulin delivery via the graft copolymerization reaction between Salecan and 2-acrylamido-2-methyl-1-propanesulfonic acid. In this study, on one hand, Salecan played a key role in modifying the structure and the pore size of the developing hydrogel. On the other hand, Salecan tuned the water content and the water release rate of the obtained hydrogel, leading to a controllable release rate of the insulin. More importantly, in vitro release experiments validated that the release of insulin from this intelligent system could be also tailored by the environmental pH of the release medium. For SGA2, the amount of encapsulated insulin released at gastric conditions (pH 1.2) was relatively low (about 26.1 wt % in 24 h), while that released at intestinal conditions (pH 7.4) increased significantly (over 50 wt % in 6 h). Furthermore, toxicity assays demonstrated that the designed hydrogel carriers were biocompatible. These characteristics make the Salecan-based hydrogel a promising candidate for protein/peptide drug delivery device.
Assuntos
Hidrogéis/química , Insulina/química , beta-Glucanas/química , Acrilamidas/química , Alcanossulfonatos/química , Animais , Células COS , Linhagem Celular , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Excipientes/química , Células HEK293 , Humanos , Concentração de Íons de Hidrogênio , Polímeros/químicaRESUMO
Various water pollution issues pose a significant threat to human water safety. Magnetic polydopamine composites (MPCs), which can be separated by magnetic fields after the adsorption process, exhibit outstanding adsorption capacity and heterogeneous catalytic properties, making them promising materials for water treatment applications. In particular, by modifying the polydopamine (PDA) coating, MPCs can acquire enhanced high reactivity, antibacterial properties, and biocompatibility. This also provides an attractive platform for further fabrication of hybrid materials with specific adsorption, catalytic, antibacterial, and water-oil separation capabilities. To systematically provide the background knowledge and recent research advances in MPCs, this paper presents a critical review of MPCs for water treatment in terms of both structure and mechanisms of effect in applications. Firstly, the impact of different PDA positions within the composite structure is investigated to summarize the optimization of properties contributed by PDA when acting as the shell, core, or bridge. The roles of various secondary modifications of magnetic materials by PDA in addressing water pollution problems are explored. It is anticipated that this work will be a stimulus for further research and development of magnetic composite materials with real-world application potential.
Assuntos
Indóis , Polímeros , Purificação da Água , Humanos , Polímeros/química , Antibacterianos , Fenômenos MagnéticosRESUMO
Severe spinal cord injury (SCI) leads to dysregulated neuroinflammation and cell apoptosis, resulting in axonal die-back and the loss of neuroelectric signal transmission. While biocompatible hydrogels are commonly used in SCI repair, they lack the capacity to support neuroelectric transmission. To overcome this limitation, we developed an injectable silk fibroin/ionic liquid (SFMA@IL) conductive hydrogel to assist neuroelectric signal transmission after SCI in this study. The hydrogel can form rapidly in situ under ultraviolet (UV) light. The mechanical supporting and neuro-regenerating properties are provided by silk fibroin (SF), while the conductive capability is provided by the designed ionic liquid (IL). SFMA@IL showed attractive features for SCI repair, such as anti-swelling, conductivity, and injectability. In vivo, SFMA@IL hydrogel used in rats with complete transection injuries was found to remodel the microenvironment, reduce inflammation, and facilitate neuro-fiber outgrowth. The hydrogel also led to a notable decrease in cell apoptosis and the achievement of scar-free wound healing, which saved 45.6 ± 10.8 % of spinal cord tissue in SFMA@IL grafting. Electrophysiological studies in rats with complete transection SCI confirmed SFMA@IL's ability to support sensory neuroelectric transmission, providing strong evidence for its signal transmission function. These findings provide new insights for the development of effective SCI treatments.
Assuntos
Fibroínas , Hidrogéis , Líquidos Iônicos , Traumatismos da Medula Espinal , Transmissão Sináptica , Hidrogéis/administração & dosagem , Hidrogéis/metabolismo , Traumatismos da Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/terapia , Injeções , Feminino , Animais , Ratos Sprague-Dawley , Ratos , Fibroínas/administração & dosagem , Fibroínas/metabolismo , Líquidos Iônicos/administração & dosagem , Líquidos Iônicos/metabolismo , Modelos Animais de Doenças , Teste de Materiais , Materiais Biocompatíveis/administração & dosagem , Materiais Biocompatíveis/metabolismo , Células PC12RESUMO
Despite orientationally variant tears of the meniscus, suture repair is the current clinical gold treatment. However, inaccessible tears in company with re-tears susceptibility remain unresolved. To extend meniscal repair tools from the perspective of adhesion and regeneration, we design a dual functional biologic-released bioadhesive (S-PIL10) comprised of methacrylated silk fibroin crosslinked with phenylboronic acid-ionic liquid loading with growth factor TGF-ß1, which integrates chemo-mechanical restoration with inner meniscal regeneration. Supramolecular interactions of ß-sheets and hydrogen bonds richened by phenylboronic acid-ionic liquid (PIL) result in enhanced wet adhesion, swelling resistance, and anti-fatigue capabilities, compared to neat silk fibroin gel. Besides, elimination of reactive oxygen species (ROS) by S-PIL10 further fortifies localized meniscus tear repair by affecting inflammatory microenvironment with dynamic borate ester bonds, and S-PIL10 continuously releases TGF-ß1 for cell recruitment and bridging of defect edge. In vivo rabbit models functionally evidence the seamless and dense reconstruction of torn meniscus, verifying that the concept of meniscus adhesive is feasible and providing a promising revolutionary strategy for preclinical research to repair meniscus tears.
Assuntos
Ácidos Borônicos , Fibroínas , Líquidos Iônicos , Menisco , Animais , Coelhos , Hidrogéis , Fator de Crescimento Transformador beta1RESUMO
Superficial cartilage defects represent the most prevalent type of cartilage injury encountered in clinical settings, posing significant treatment challenges. Here, we fabricated a cartilage extracellular matrix mimic hydrogel (GHC, consisting of Gelatin, Hyaluronic acid, and Chondroitin sulfate) to avoid the exacerbation of cartilage deterioration, which is often driven by the accumulation of reactive oxygen species (ROS) and a pro-inflammatory microenvironment. The GHC hydrogel exhibited multifunctional properties, including in situ formation, tissue adhesiveness, anti-ROS capabilities, and the promotion of chondrogenesis. The enhancement of tissue adhesion was achieved by chemically modifying hyaluronic acid and chondroitin sulfate with o-nitrobenzene, enabling a covalent connection to the cartilage surface upon light irradiation. In vitro characterization revealed that GHC hydrogel facilitated chondrocyte adhesion, migration, and differentiation into cartilage. Additionally, GHC hydrogels demonstrated the ability to scavenge ROS in vitro and inhibit the production of inflammatory factors by chondrocytes. In the animal model of superficial cartilage injury, the hydrogel effectively promoted cartilage ECM regeneration and facilitated the interface integration between the host tissue and the material. These findings suggest that the multifunctional GHC hydrogels hold considerable promise as a strategy for cartilage defect repair. STATEMENT OF SIGNIFICANCE: : Superficial cartilage defects represent the most prevalent type of cartilage injury encountered in the clinic. Previous cartilage tissue engineering materials are only suitable for full-thickness cartilage defects or osteochondral defects. Here, we developed a multifunctional GHC hydrogel composed of gelatin, hyaluronic acid, and chondroitin sulfate, which are natural cartilage extracellular matrix components. The drug-free and cell-free hydrogel not only avoids immune rejection and drug toxicity, but also shows good mechanical properties and biocompatibility. More importantly, the GHC hydrogel could adhere tightly to the superficial cartilage defects and promote cartilage regeneration while protecting against oxidation. This natural ingredients and multifunctional hydrogel is a potential material for repairing superficial cartilage defects.
RESUMO
Magnetic nanoparticle materials which could be used to remove tetracycline were confined seriously due to their poor stability and unsatisfactory reusability. Here, we facilely prepared novel zeolitic imidazolate framework-8 (ZIF-8) functionalized magnetic nanoparticles (Fe3O4@PDA-ZIF-8) adsorbent utilizing polydopamine as a bond to establish a connection between zeolitic imidazolate framework-8 and Fe3O4, which could improve the stability of magnetic nanoparticles and enhance the tetracycline adsorption capacity simultaneously. The prepared nanocomposites were characterized and their TC adsorption abilities under various experiment conditions (contact time, TC initial concentration and pH values) were also investigated. Experimental results proved that the prepared adsorbent showed superior TC adsorption capacities (92.01 mg/g at pH = 7). Further, the adsorption mechanisms were comprehensively studied and the prepared adsorbent showed satisfactory stability and reusability during the cycle experiment. Altogether, our findings provided a feasible way to design and construct functional magnetic MOF materials for enhancing tetracycline adsorption from wastewater.
Assuntos
Nanopartículas de Magnetita , Poluentes Químicos da Água , Zeolitas , Adsorção , Antibacterianos/química , Indóis , Polímeros , Tetraciclina/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Zeolitas/químicaRESUMO
Fenton-like catalysts represent a family of promising materials to degrade micropollutants from contaminated water. However, the practical applications of Fenton-like catalysts are mainly limited by low catalytic degradation efficiency and stability. Herein, for the first time, rapid fabrication of Ag-decorated Fe3O4/polydopamine (FPA) microspheres was achieved via the help of UV irradiation, and the designed FPA microspheres were employed as Fenton-like catalysts to degrade micropollutants. Results showed that UV irradiation could activate the generation of the polydopamine shell and accelerate the Ag deposition, which played a crucial role in the rapid synthesis of highly active and stable FPA catalysts. Relative to reported catalysts, these FPA microspheres exhibited outstanding catalytic degradation performance, achieving 94.38% removal of tetracycline within 60 min. This work will provide a convenient strategy in the sustainable and efficient purification of wastewater to improve the quality of human life.
Assuntos
Peróxido de Hidrogênio , Polímeros , Catálise , Humanos , IndóisRESUMO
Bacterial infections are a common problem associated with wound treatment that imposes a significant burden on healthcare systems and patients. As a result, healthcare providers urgently need new treatment strategies to protect people. Hydrogel biomaterials with inherent antimicrobial properties offer an attractive and viable solution to this issue. Here, for the first time, we have developed a new efficient synthetic strategy to prepare cationic hydrogels (PHCI) with intrinsically efficient antimicrobial properties by chemically cross-linking trans-1,4-cyclohexanediamine with 1,3-dibromo-2-propanol using a condensation reaction without the use of toxic cross-linking agents. As expected, the prepared PHCI hydrogel possessed an inherent antibacterial ability that can adsorb and kill Staphylococcus aureus and Escherichia coli electrostatically. Notably, in vivo experiments on normal and diabetic rat models confirmed that the PHCI hydrogel can quickly stop bleeding, efficiently kill bacteria, promote the conversion of macrophages from the proinflammatory M1 phenotype to the repaired M2 phenotype, and accelerate collagen deposition and blood vessel formation, thereby achieving rapid wound healing. Overall, this work presents an effective antibacterial dressing that might provide a facile but effective approach for clinical wound management.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Infecções Bacterianas/tratamento farmacológico , Hidrogéis/química , Hidrogéis/farmacologia , Cicatrização/efeitos dos fármacos , Infecção dos Ferimentos/tratamento farmacológico , Animais , Antibacterianos/uso terapêutico , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Diabetes Mellitus Experimental/complicações , Escherichia coli/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Hemostáticos/química , Hemostáticos/farmacologia , Hemostáticos/uso terapêutico , Hidrogéis/uso terapêutico , Masculino , Camundongos , Ratos Sprague-Dawley , Staphylococcus aureus/efeitos dos fármacos , Infecção dos Ferimentos/complicações , Infecção dos Ferimentos/metabolismo , Infecção dos Ferimentos/patologiaRESUMO
With the increasingly severe international security situation, the application of explosives is more and more extensive, and the probes that can detect the explosives quickly and efficiently have attracted people's attention. In this work, two novel probes T1 and T2 were synthesized through vitamin E succinate and tetraphenylethylene derivative. Fluorescence spectra showed that both T1 and T2 had a typical aggregation-induced emission (AIE) effect in THF/H2O solution, and explosive FOX-7 could effectively quench this fluorescence without being affected by other explosives or ions. The filter paper and cotton rods prepared with these two probes could detect FOX-7 specifically, which also provided the possibility for practical application on the battlefield.
RESUMO
Magnetic nanoparticles that can be employed as Fenton-like catalysts Fenton-like catalysts are attractive materials for degrading antibiotics. In this study, we facilely prepared novel magnetic pullulan (MP) hydrogels by doping modified magnetic nanoparticles into pullulan matrices, which could enhance catalytic degradation performance and strengthen the stability of resulting hydrogels. This is the first time that MP hydrogels have been fabricated successfully and used as Fenton-like catalysts for tetracycline hydrochloride (TCH) degradation. MP hydrogels were characterized and their catalytic TCH degradation abilities were also investigated. The optimized conditions (pH value, Fe3O4 content, H2O2 content and TCH concentration) for TCH degradation were investigated. The optimized system showed excellent degradation efficiency for TCH. Further, the degradation mechanism was comprehensively studied. Finally, synthesized MP hydrogels showed impressive reusability and stability in the cycle experiment. Thus, our findings would open new possibilities to develop magnetic hydrogels in eliminating antibiotic contaminants.
Assuntos
Antibacterianos/isolamento & purificação , Glucanos/química , Hidrogéis/química , Nanopartículas Magnéticas de Óxido de Ferro/química , Águas Residuárias/química , Antibacterianos/metabolismo , Catálise , Peróxido de Hidrogênio/química , Ferro/química , Tetraciclina/isolamento & purificação , Tetraciclina/metabolismo , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodosRESUMO
Fluorescent sensor has been noticed in detecting system due to its sensitive, selective, operational simplicity and low cost. We designed a coumarin-connected carboxylic indolium sensor molecule that is water-soluble and cytomembrane-permeable. This infrared (IR) emitter is selectively sensitive towards cyanide detection in aqueous media according to CN- nucleophilic attack on the indole C=N function. Upon the addition of CN- anion, the color of sensor in water varied from blue to colorless by naked eyes and fluorescence quenching was observed by spectroscopic method. This was because the intramolecular charge transfer (ICT) effect occurred when the fluorescent sensor was added with CN-. The minimum detection limit of the sensor's fluorescence response to CN- is 4.44â¯×â¯10-7â¯mol/L. Furthermore, the cytotoxicity test shows the sensor has lower cytotoxicity, and indicates that this sensor can be utilized for practical detection of trace cyanide in wastewater.
Assuntos
Cumarínicos/química , Cianetos/análise , Indóis/química , Imagem Molecular , Água/química , Animais , Ânions , Morte Celular , Cumarínicos/síntese química , Indóis/síntese química , Melanoma Experimental/patologia , Camundongos , Modelos Moleculares , Espectroscopia de Prótons por Ressonância Magnética , Soluções , Espectrofotometria UltravioletaRESUMO
Polysaccharide is a renewable, biocompatible and biodegradable material that has received considerable attention. In this work, a series of polysaccharide gels were synthesized from the chemical cross-linking of pullulan with diglycerols. The effects of the diglycerol chain length on the performance of the gels were evaluated by XRD, TGA, SEM, rheological testings and swelling measurements. Overall, increasing the chain length resulted in a smaller pore size and stronger mechanical strength. Tetramethylene glycol diglycidyl ether (longest chain length)-derived Gel-T, which had the best performance (acceptable porous structure, good swelling ability and strong rigidity), was used to produce a nanocomposite hydrogel with montmorillonite (MMT). The incorporation of MMT led to a decrease in gel swelling and an increase in gel strength. The obtained nanocomposite system exhibited excellent adsorption properties (80â¯mg/g) towards crystal violet, and the adsorption behaviours were well represented by the pseudo-second-order kinetic and Langmuir isotherm models. Altogether, this study provides a better understanding of the structure-function relationships of pullulan-constructed hydrogel materials and will help to design more practical adsorbents for dye removal.
Assuntos
Glucanos/síntese química , Hidrogéis/síntese química , Nanocompostos/química , Polissacarídeos/síntese química , Águas Residuárias/química , Purificação da Água , Adsorção , Bentonita/química , Violeta Genciana/química , Glicerol/química , Cinética , Fenômenos Mecânicos , Porosidade , Poluentes Químicos da Água/químicaRESUMO
In this work, we designed a kind of novel fluorescent probes based on naphthalene-benzoindole conjugate derived for sensitively monitoring the pH fluctuation in environment and biological systems. In the spectral method, these two probes both show significant red shift, color change and fluorescence quenching due to the effect of intramolecular charge transfer (ICT) mechanism. Moreover, we found that the probe bearing with carboxyl group displayed a more hydrophilicity than the one bearing with hydrogen atom instead, and the former exhibits a faster response and higher fluorescence intensity. Besides, the probe bearing with carboxyl group shows lower cytotoxicity, evidences by the vitro study. It indicates that this probe has great potential in application in living cell imaging as well as pH-fluctuation monitoring.
Assuntos
Corantes Fluorescentes/química , Indóis/química , Naftalenos/química , Animais , Linhagem Celular Tumoral , Colorimetria/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Humanos , Concentração de Íons de Hidrogênio , Indóis/síntese química , Indóis/toxicidade , Camundongos , Microscopia de Fluorescência/métodos , Modelos Químicos , Naftalenos/síntese química , Naftalenos/toxicidadeRESUMO
Fenton technology has been proven an effective way to remove dyes from wastewater. However, the demanding pH of reaction condition restricted its wide application. In this study, we report a novel Fenton-like catalyst (Fe3O4@PDA-MnO2) facilely synthesized by polydopamine (PDA) coating and MnO2 depositing onto the surface of Fe3O4 nanoparticles. This method for preparing magnetic Fe3O4@PDA-MnO2 catalyst could avoid the agglomeration of MnO2 nanoparticles and make the catalyst collect easily from the solution. The resultant Fe3O4@PDA-MnO2 nanoparticles possess core-shell nanostructure. Fe3O4@PDA-MnO2 catalyst could cooperate with hydrogen peroxide to form a Fenton-like reagent for the removal of methylene blue (MB) and performed excellent catalytic activities towards MB, including high degradation efficiency of 97.36% after 240 min. Besides, Fe3O4@PDA-MnO2 can retain excellent reusability after 5 using-cycles. More importantly, the catalyst can be used in a wide pH range from 2 to 12 in Fenton systems, demonstrating that the degradation process is independent on pH which is different from most reported studies. Also, Fe3O4@PDA-MnO2 could still keep more than 75% removal efficiency of MB in industrial wastewater treatment application. Therefore, the synthesized Fe3O4@PDA-MnO2 would be a promising device for the removal of dyes from wastewater.