RESUMO
Tetraallylsilane can undergo either a mono or double rearrangement when treated with iodine (I2). The extent of rearrangement depends on the equivalents of I2 used, where 1 equivalent gives high yields of mono-rearranged products and excess (e.g., 3 equivalents) causes double rearrangement to occur. This transformation can be applied to the synthesis of potentially valuable silicon-stereogenic organosilanes.
Assuntos
Iodo , Silanos , Silício , Silanos/química , Iodo/química , Silício/química , Compostos de Organossilício/química , Estereoisomerismo , Estrutura MolecularRESUMO
Objective.The objective of this study is to explore the capabilities of photon-counting computed tomography (PCCT) in simultaneously imaging and differentiating materials with close atomic numbers, specifically barium (Z= 56) and iodine (Z= 53), which is challenging for conventional computed tomography (CT).Approach.Experiments were conducted using a bench-top PCCT system equipped with a cadmium zinc telluride detector. Various phantom setups and contrast agent concentrations (1%-5%) were employed, along with a biological sample. Energy thresholds were tuned to the K-edge absorption energies of barium (37.4 keV) and iodine (33.2 keV) to capture multi-energy CT images. K-edge decomposition was performed using K-edge subtraction and principal component analysis (PCA) techniques to differentiate and quantify the contrast agents.Main results.The PCCT system successfully differentiated and accurately quantified barium and iodine in both phantom combinations and a biological sample, achieving high correlations (R2≈1) between true and reconstructed concentrations. PCA outperformed K-edge subtraction, particularly in the presence of calcium, by providing superior differentiation between barium and iodine.Significance.This study demonstrates the potential of PCCT for reliable, detailed imaging in both clinical and research settings, particularly for contrast agents with similar atomic numbers. The results suggest that PCCT could offer significant improvements in imaging quality over conventional CT, especially in applications requiring precise material differentiation.
Assuntos
Bário , Iodo , Imagens de Fantasmas , Fótons , Tomografia Computadorizada por Raios X , Iodo/química , Tomografia Computadorizada por Raios X/métodos , Bário/química , Processamento de Imagem Assistida por Computador/métodos , Meios de Contraste/química , Análise de Componente PrincipalRESUMO
Energy conversion and pollutant degradation are critical for advancing sustainable technologies, yet they often encounter challenges related to charge recombination and efficiency limitations. This study explores iodine-doped TiO2 nanoparticles as a potential solution for enhancing both energy conversion and pollutant degradation. The nanoparticles were synthesized via the sol-gel method with varying iodine precursor concentrations (0.025-0.1 M) and were characterized for their structural, compositional, and optical properties, particularly in relation to their photocatalytic performance in Rhodamine-B dye degradation. X-ray diffraction confirmed a tetragonal anatase crystal structure, with the average crystallite size decreasing from 10.06 nm to 8.82 nm with increase in iodine concentration. Selected area electron diffraction patterns verified the polycrystalline nature of the nanoparticles. Dynamic light scattering analysis showed hydrodynamic radii ranging from 95 to 125 nm. Fourier-transform infrared spectroscopy identified metal-oxygen vibrations at 441 cmâ»1, and electron microscopy confirmed the spherical morphology of the nanoparticles. Elemental analysis detected the presence of Ti, O, and I in the samples. Diffuse reflectance spectroscopy indicated the optical absorption edges for the doped samples in the visible region from which the corresponding band gap values were deduced. Photoluminescence spectroscopy revealed that the sample with 0.1 M iodine exhibit the lowest emission intensity, suggesting reduced charge recombination. Notably, 0.1 M iodine doped TiO2 samples demonstrated the highest photocatalytic efficiency, achieving 82.36% degradation of Rhodamine-B dye within 140 min under visible light. Additionally, ab-initio density functional theory calculations were performed to investigate the structural, optical, and adsorption properties of TiO2, iodine-doped TiO2, Rhodamine-B, and their composites, providing further insight into the enhanced photocatalytic activity observed in the experiments.
Assuntos
Iodo , Nanopartículas , Rodaminas , Titânio , Titânio/química , Rodaminas/química , Iodo/química , Nanopartículas/química , Catálise , Poluentes Químicos da Água/química , Difração de Raios X , Corantes/química , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Kappaphycus alvarezii is the most widely cultivated seaweed globally. The use of the protein contained in K. alvarezii as an alternative protein source seems to be an effective countermeasure against the protein crisis. Here, we identified the iodine chemical species in K. alvarezii and developed an iodine reduction method. We used various fractionation methods and showed that almost all the iodine in the K. alvarezii alkali extract is present as an iodinated protein, and reducing the amount of iodine per protein was difficult. Subsequently, an iodine reduction method was established to cleave the covalent bonds between the protein and iodine, and we could successfully reduce the amount of iodine per protein by approximately half.
Assuntos
Iodo , Alga Marinha , Iodo/química , Iodo/análise , Alga Marinha/química , Proteínas de Plantas/química , Rodófitas/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Oxirredução , Algas ComestíveisRESUMO
The reagent system based on the combined use of Et3SiH/I2 acts as an efficient N-glycosidation promoter for the synthesis of natural and sugar-modified nucleosides. An analysis of reaction stereoselectivity in the absence of C2-positioned stereodirecting groups revealed high selectivity with six-membered substrates, depending on the nucleophilic character of the nucleobase or based on anomerization reactions. The synthetic utility of the Et3SiH/I2-mediated N-glycosidation reaction was highlighted by its use in the synthesis of the investigational drug apricitabine.
Assuntos
Iodo , Nucleosídeos , Nucleosídeos/química , Nucleosídeos/síntese química , Iodo/química , Glicosilação , Silanos/química , Glicosídeos/química , Glicosídeos/síntese química , Açúcares/químicaRESUMO
Lappaconitine, a diterpene alkaloid isolated from Aconitum sinomontanum Nakai, exhibits a wide range of biological activities, making it a promising candidate for the development of novel derivatives with therapeutic potential. In our research, we executed a two-step transformation via oxidative cleavage of lappaconitine's vicinal diol using the hypervalent iodine reagent PhI(OAc)2, followed by strong alkaline hydrolysis. This approach yielded four new unanticipated compounds, whose structures were identified by spectroscopic methods and/or X-ray crystallography. Thus, we proposed plausible reaction mechanisms for their formations and particularly investigated the remarkable diastereoselectivity for the formation of single stereoisomer 8 observed during the alkaline hydrolysis step. Among them, compound 8 (code name: QG3030) demonstrated both enhanced osteogenic differentiation of human mesenchymal stem cells and significant osteogenic effect in an ovariectomized rat model with no acute oral toxicity.
Assuntos
Aconitina , Iodo , Aconitina/análogos & derivados , Aconitina/química , Aconitina/farmacologia , Humanos , Animais , Estrutura Molecular , Ratos , Iodo/química , Alcaloides/química , Alcaloides/farmacologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Aconitum/química , Cristalografia por Raios X , Osteogênese/efeitos dos fármacos , Estereoisomerismo , Diferenciação Celular/efeitos dos fármacosRESUMO
Biomaterial-associated infections caused by bacteria pose a great threat to human health, and therefore, various antibacterial coatings have been developed to control bacterial infections. Povidone iodine (PVP-I) is a broad-spectrum antimicrobial agent without drug resistance to most pathogenic microorganisms and has been widely used in the clinic. However, its applications in the field of coatings are limited due to its strong water solubility. Here, we used initiated Chemical Vapor Deposition (iCVD) technique to synthesize cross-linked poly(N-vinylpyrrolidone-co-ethylene glycol dimethacrylate) (PVE) coatings to firmly immobilize poly(N-vinylpyrrolidone) (PVP) on surfaces. After complexation with iodine, PVE-I coatings exhibited potent bacteria-killing and antifouling activities against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus in vitro owing to the antibacterial effect of iodine and the hydrophilicity of VP, respectively. The killing and antifouling effects were positively correlated with the VP content. The PVE-I-2 coating displayed excellent anti-infection performance in a rat subcutaneous implantation model in vivo. This study provided a simple method for preparing stable povidone iodine coatings on surfaces via solvent-free iCVD, and combined bacteria-killing and antifouling strategies to fabricate multifunctional antibacterial coatings against bacterial infections on biomaterial surfaces.
Assuntos
Antibacterianos , Escherichia coli , Staphylococcus aureus , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Animais , Ratos , Iodo/química , Iodo/farmacologia , Povidona-Iodo/farmacologia , Povidona-Iodo/química , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/química , Povidona/química , Testes de Sensibilidade Microbiana , Propriedades de SuperfícieRESUMO
A wide range of 3-selenylindoles were synthesized via an eco-friendly approach that uses Oxone® as the oxidant in the presence of a catalytic amount of iodine. This mild and economical protocol showed broad functional group tolerance and operational simplicity. A series of novel selenylindoles bearing a benzenesulfonamide moiety were also synthesized and evaluated as carbonic anhydrase inhibitors of the human (h) isoforms hCa I, II, IX, and XII, which are involved in pathologies such as glaucoma and cancer. Several derivatives showed excellent inhibitory activity towards these isoforms in the nanomolar range, lower than that shown by acetazolamide.
Assuntos
Benzenossulfonamidas , Inibidores da Anidrase Carbônica , Anidrases Carbônicas , Indóis , Iodo , Oxirredução , Sulfonamidas , Inibidores da Anidrase Carbônica/química , Inibidores da Anidrase Carbônica/farmacologia , Inibidores da Anidrase Carbônica/síntese química , Sulfonamidas/química , Sulfonamidas/farmacologia , Sulfonamidas/síntese química , Humanos , Anidrases Carbônicas/metabolismo , Indóis/química , Indóis/farmacologia , Indóis/síntese química , Iodo/química , Compostos Organosselênicos/química , Compostos Organosselênicos/farmacologia , Compostos Organosselênicos/síntese química , Relação Estrutura-Atividade , Estrutura MolecularRESUMO
Photon-counting detector (PCD)-based computed tomography (CT) offers several advantages over conventional energy-integrating detector-based CT. Among them, the ability to discriminate energy exhibits significant potential for clinical applications because it provides material-specific information. That is, material decomposition (MD) can be achieved through energy discrimination. In this study, deep learning-based material decomposition was performed using live animal data. We propose MD-Unet, which is a deep learning strategy for material decomposition based on an Unet architecture trained with data from three energy bins. To mitigate the data insufficiency, we developed a pretrained model incorporating various simulation data forms and augmentation strategies. Incorporating these approaches into model training results in enhanced precision in material decomposition, thereby enabling the identification of distinct materials at individual pixel locations. The trained network was applied to the acquired animal data to evaluate material decomposition results. Compared with conventional methods, the newly generated MD-Unet demonstrated more accurate material decomposition imaging. Moreover, the network demonstrated an improved material decomposition ability and significantly reduced noise. In addition, they can potentially offer an enhancement level similar to that of a typical contrast agent. This implies that it can acquire images of the same quality with fewer contrast agents administered to patients, thereby demonstrating its significant clinical value.
Assuntos
Cálcio , Aprendizado Profundo , Iodo , Fótons , Tomografia Computadorizada por Raios X , Iodo/química , Tomografia Computadorizada por Raios X/métodos , Animais , Cálcio/análise , Processamento de Imagem Assistida por Computador/métodos , Meios de Contraste/químicaRESUMO
The United Nations proposed the Sustainable Development Goals with the aim to make human settlements in cities resilient and sustainable. The excessive discharge of urban waste including sludge and garden waste can pollute groundwater and lead to the emission of greenhouse gases (e.g., CH4). The proper recycling of urban waste is essential for responsible consumption and production, reducing environmental pollution and addressing climate change issues. This study aimed to prepare biochar with high adsorption amounts of iodine using urban sludge and peach wood from garden waste. The study was conducted to examine the variations in the mass ratio between urban sludge and peach wood (2/1, 1/1, and 1/2) as well as pyrolysis temperatures (300 °C, 500 °C, and 700 °C) on the carbon yield and adsorption capacities of biochar. Scanning electron microscopy, Brunauer-Emmett-Teller analysis, Fourier transform infrared spectrometry, powder X-ray diffraction, and elemental analysis were used to characterize the biochar produced at different pyrolysis temperatures and mass ratios. The results indicate that the carbon yield of biochar was found to be the highest (>60%) at a pyrolysis temperature of 300 °C across different pyrolysis temperatures. The absorbed amounts of iodine in the aqueous solution ranged from 86 to 223 mg g-1 at a mass ratio of 1:1 between urban sludge and peach wood, which were comparably higher than those observed in other mass ratios. This study advances water treatment by offering a cost-effective method by using biochar derived from the processing of urban sludge and garden waste.
Assuntos
Carvão Vegetal , Iodo , Pirólise , Esgotos , Carvão Vegetal/química , Iodo/química , Esgotos/química , Adsorção , Temperatura , Jardins , Espectroscopia de Infravermelho com Transformada de Fourier , CidadesRESUMO
Iodine (I2) as a broad-spectrum antiseptic has been widely used for treating bacterial infections. However, I2 has low water-solubility and sublimes under ambient conditions, which limits its practical antibacterial applications. The highly specific and sensitive reaction between I2 and starch discovered 200 years ago has been extensively applied in analytical chemistry, but the antibacterial activity of the I2-starch complex is rarely investigated. Herein, we develop a novel type of iodine-based antiseptics, iodine-soluble starch (I2-SS) cryogel, which can dissolve in water instantly and almost completely kill bacteria in 10 min at 2 µg/mL of I2. Although KI3 and the commercially available povidoneiodine (I2-PVP) solutions show similar antibacterial efficacy, the high affinity of I2 to SS largely enhances the shelf stability of the I2-SS solution with â¼73 % I2 left after one-week storage at room temperature. In sharp contrast, â¼8.5 % and â¼2.5 % I2 are detected in KI3 and I2-PVP solutions, respectively. Mechanistic study reveals that the potent antibacterial effect of I2-SS originates from its attack on multiple bacterial targets. The outstanding antibacterial activity, capability of accelerating wound healing, and good biocompatibility of I2-SS are verified through further in vivo experiments. This work may promote the development of next-generation iodine-based antiseptics for clinical use.
Assuntos
Antibacterianos , Anti-Infecciosos Locais , Criogéis , Iodo , Solubilidade , Amido , Água , Iodo/química , Iodo/farmacologia , Amido/química , Amido/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Anti-Infecciosos Locais/farmacologia , Anti-Infecciosos Locais/química , Água/química , Criogéis/química , Animais , Staphylococcus aureus/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Povidona-Iodo/química , Povidona-Iodo/farmacologia , Escherichia coli/efeitos dos fármacos , Cicatrização/efeitos dos fármacosRESUMO
Nanozyme-mediated antioxidative therapy is a promising star for treating a myriad of important diseases through eliminating excessive reactive oxygen species (ROS) such as O2·- and H2O2, a critical mechanism for inflammatory bowel disease (IBD). This work provides a high biocompatibility iodine-copper-zinc covalent doped carbon dots (Cu,Zn,I-CDs) with the catalase (CAT)-, superoxide dismutase (SOD)- and glutathione peroxidase (GPx)-like catalytic activities for treating ulcerative colitis (UC) by scavenging overproduced ROS. We found that I dopant aids in counteracting the positive charge at Cu,Zn dopants brought on by low pH, enabling Cu,Zn,I-CDs to process strong triple antioxidant nanozyme activities rather than Cu,Zn-CDs. Vitro experiments displayed that the Cu,Zn,I-CDs could scavenge the excessive ROS to protect cellular against oxidative stress and reduce the expression of proinflammatory cytokines, such as TNF-α, IL-1ß, and IL-6. In sodium dextran sulfate (DSS)-induced colitis mice models, Cu,Zn,I-CDs with excellent biocompatibility could effectively relieve the inflammation of the colon, containing the reduction of the colon length, the damaged epithelium, the infiltration of inflammatory cells, and upregulation of antioxidant genes. Therefore, the therapy of Cu,Zn,I-CD antioxidant nanozymes is an effective approach and provides a novel strategy for UC treatment.
Assuntos
Antioxidantes , Carbono , Colite , Cobre , Sulfato de Dextrana , Pontos Quânticos , Zinco , Animais , Camundongos , Cobre/química , Cobre/farmacologia , Carbono/química , Antioxidantes/química , Antioxidantes/farmacologia , Pontos Quânticos/química , Zinco/química , Colite/tratamento farmacológico , Colite/induzido quimicamente , Colite/metabolismo , Colite/patologia , Espécies Reativas de Oxigênio/metabolismo , Iodo/química , Iodo/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Humanos , Superóxido Dismutase/metabolismo , Catalase/metabolismo , Camundongos Endogâmicos C57BLRESUMO
Simultaneous dual-contrast imaging of iodine and bismuth has shown promise in prior phantom and animal studies utilizing spectral CT. However, it is noted that in previous studies, Pepto-Bismol has frequently been employed as the source of bismuth, exceeding the recommended levels for human subjects. This investigation sought to assess the feasibility of visually differentiating and precisely quantifying low-concentration bismuth using clinical dual-source photon-counting CT (PCCT) in a scenario involving both iodinated and bismuth-based contrast materials. Four bismuth samples (0.6, 1.3, 2.5, and 5.1 mg/mL) were prepared using Pepto-Bismol, alongside three iodine rods (1, 2, and 5 mg/mL), inserted into multi-energy CT phantoms with three different sizes, and scanned on a PCCT system at three tube potentials (120, 140, and Sn140 kV). A generic image-based three-material decomposition method generated iodine and bismuth maps, with mean mass concentrations and noise levels measured. The root-mean-square errors for iodine and bismuth determined the optimal tube potential. The tube potential of 140 kV demonstrated optimal quantification performance when both iodine and bismuth were considered. Distinct differentiation of iodine rods with all three concentrations and bismuth samples with mass concentrations ≥ 1.3 mg/mL was observed across all phantom sizes at the optimal kV setting.
Assuntos
Bismuto , Meios de Contraste , Iodo , Imagens de Fantasmas , Fótons , Tomografia Computadorizada por Raios X , Bismuto/química , Iodo/química , Tomografia Computadorizada por Raios X/métodos , Meios de Contraste/química , HumanosRESUMO
Hypervalent iodine reagents have undergone significant development and widespread application in the functionalization of carbohydrates. This is primarily attributed to their exceptional properties, including mildness, ease of handling, high selectivity, environmental friendliness, and stability. This review aims to emphasize the utilization of hypervalent iodine compounds in the functionalization of carbohydrates. The present article covers various aspects, including glycal functionalization, C-H or N-H insertion reactions, O-arylations, C-2 deoxy-2-iodo glycoconjugates, iminosugars, and C3-oxo-glycals, achieved through the use of hypervalent iodine reagents/catalysts. Additionally, it explores hypervalent iodine-mediated bioactive 1,3,5-trioxocane synthesis followed by rare sugars synthesis.
Assuntos
Carboidratos , Iodo , Iodo/química , Carboidratos/químicaRESUMO
The simultaneous discrimination and detection of multiple anions in an aqueous solution has been a major challenge due to their structural similarity and low charge radii. In this study, we have constructed a supramolecular fluorescence sensor array based on three host-guest complexes to distinguish five anions (F-, Cl-, Br-, I-, and ClO-) in an aqueous solution using anionic-induced fluorescence quenching combined with linear discriminant analysis. Due to the different affinities of the three host-guest complexes for each anion the anion quenching efficiency for each host-guest complex was likewise different, and the five anions were well recognized. The fluorescence sensor array not only distinguished anions at different concentrations (0.5, 10, and 50 µM) with 100% accuracy but also showed good linearity within a certain concentration range. The limit of detection (LOD) was < 0.5 µM. Our interference study showed that the developed sensor array had good anti-interference ability. The practicability of the developed sensor array was also verified by the identification and differentiation of toothpaste brands with different fluoride content and the prediction of the iodine concentration in urine combined with machine learning.
Assuntos
Ânions , Iodo , Limite de Detecção , Aprendizado de Máquina , Espectrometria de Fluorescência , Ânions/urina , Ânions/química , Iodo/urina , Iodo/química , Espectrometria de Fluorescência/métodos , Cremes Dentais/química , Corantes Fluorescentes/química , Fluoretos/química , Fluoretos/urina , Análise DiscriminanteRESUMO
Ethynylbenziodoxol(on)es (EB(X)xs) reagents have emerged as useful reagents for peptide/protein modification due to their versatile reactivity and high selectivity. Herein, we report the successful introduction of ethynylbenziodoxoles (EBxs) on different amino acid building blocks (Lys/Orn/Dap), and show their compatibility with both solid phase peptide synthesis (SPPS) and solution phase peptide synthesis (SPS). The selective incorporation of the EBx core into peptide sequences enable efficient macrocyclizations under mild conditions for the synthesis of topologically unique cyclic and bicyclic peptides.
Assuntos
Aminoácidos , Iodo , Peptídeos , Aminoácidos/química , Ciclização , Iodo/química , Peptídeos/química , Peptídeos/síntese química , Técnicas de Síntese em Fase Sólida , Estrutura Molecular , Peptídeos Cíclicos/química , Peptídeos Cíclicos/síntese químicaRESUMO
This study addresses the morphological and chemical characterization of PGS scaffolds after (6, 12, 18, 24, and 30 min) residence in undoped pyrrole plasma (PGS-PPy) and the evaluation of cell viability with human dental pulp stem cells (hDPSCs). The results were compared with a previous study that used iodine-doped pyrrole (PGS-PPy/I). Analyses through SEM and AFM revealed alterations in the topography and quantity of deposited PPy particles. FTIR spectra of PGS-PPy scaffolds confirmed the presence of characteristic absorption peaks of PPy, with higher intensities observed in the nitrile and -C≡C- groups compared to PGS-PPy/I scaffolds, while raman spectra indicated a lower presence of polaron N+ groups. On the other hand, PGS scaffolds modified with PPy exhibited lower cytotoxicity compared to PGS-PPy/I scaffolds, as evidenced by the Live/Dead assay. Furthermore, the PGS-PPy scaffolds at 6 and 12 min, and particularly the PGS-PPy/I scaffold at 6 min, showed the best results in terms of cell viability by the fifth day of culture. The findings of this study suggest that undoped pyrrole plasma modification for short durations could also be a viable option to enhance the interaction with hDPSCs, especially when the treatment times range between 6 min and 12 min.
Assuntos
Sobrevivência Celular , Decanoatos , Polpa Dentária , Iodo , Polímeros , Pirróis , Células-Tronco , Alicerces Teciduais , Humanos , Polpa Dentária/citologia , Pirróis/química , Células-Tronco/citologia , Iodo/química , Alicerces Teciduais/química , Polímeros/química , Sobrevivência Celular/efeitos dos fármacos , Decanoatos/química , Glicerol/química , Glicerol/análogos & derivados , Células Cultivadas , Materiais Biocompatíveis/química , Teste de Materiais , Gases em Plasma/química , Engenharia TecidualRESUMO
Freeze-induced acceleration of I- oxidation and the consequent iodination of dissolved organic matter (DOM) contribute to the formation of organoiodine compounds (OICs) in cold regions. The formed OICs may be a potentially important source of risk and are very closely with the environment and human health. Herein, we investigated the acceleration effects of the freeze process on I- oxidation and the formation of OICs. In comparison to reactive iodine species (RIS) formed in aqueous solutions, I- oxidation and RIS formation were greatly enhanced in frozen solution and were affected by pH, and the content of I- and O2. Freeze-thaw process further promoted I- oxidation and the concentration of RIS reached 45.7 µmol/L after 6 freeze-thaw cycles. The consequent products of DOM iodination were greatly promoted in terms of both concentration and number. The total content of OICs ranged from 0.02 to 2.83 µmol/L under various conditions. About 183-1197 OICs were detected by Fourier transform ion cyclotron resonance mass spectrometry, and more than 96.2% contained one or two iodine atoms. Most OICs had aromatic structures and were formed via substitution and addition reactions. Our findings reveal an important formation pathway for OICs and shed light on the biogeochemical cycling of iodine in the natural aquatic environment.
Assuntos
Congelamento , Iodetos , Oxirredução , Poluentes Químicos da Água , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Iodetos/química , Halogenação , Iodo/químicaRESUMO
Here, lignin and nano-clay were used to prepare novel composite adsorbents by one-step carbonization without adding activators for radioactive iodine capture. Specially, 1D nano-clay such as halloysite (Hal), palygorskite (Pal) and sepiolite (Sep) were selected as skeleton components, respectively, enzymatic hydrolysis lignin (EHL) as carbon source, lignin based porous carbon/nano-clay composites (ELC-X) were prepared through ultrasonic impregnation, freeze drying, and carbonization. Characterization results indicated lignin based porous carbon (ELC) well coated on the surface of nano-clay, and made its surface areas increase to 252 m2/g. These composites appeared the micro-mesoporous hierarchical structure, considerable N doping and good chemical stability. Results of adsorption experiments showed that the introduction of ELC could well promote iodine vapor uptake of nano-clay, and up to 435.0 mg/g. Meanwhile, the synergistic effect between lignin based carbon and nano-clay was very significant for the adsorption of iodine/n-hexane and iodine ions, their capacity were far exceed those of a single material, respectively. The relevant adsorption kinetic and thermodynamics, and mechanism of ELC-X composites were clarified. This work provided a class of low-cost and environmentally friendly adsorbents for radioactive iodine capture, and opened up ideas for the comprehensive utilization of waste lignin and natural clay minerals.
Assuntos
Carbono , Argila , Iodo , Lignina , Lignina/química , Argila/química , Carbono/química , Adsorção , Porosidade , Iodo/química , Cinética , Nanocompostos/química , TermodinâmicaRESUMO
The biogeochemical processes of iodine are typically coupled with organic matter (OM) and the dynamic transformation of iron (Fe) minerals in aquifer systems, which are further regulated by the association of OM with Fe minerals. However, the roles of OM in the mobility of iodine on Fe-OM associations remain poorly understood. Based on batch adsorption experiments and subsequent solid-phase characterization, we delved into the immobilization and transformation of iodate and iodide on Fe-OM associations with different C/Fe ratios under anaerobic conditions. The results indicated that the Fe-OM associations with a higher C/Fe ratio (=1) exhibited greater capacity for immobilizing iodine (â¼60-80% for iodate), which was attributed to the higher affinity of iodine to OM and the significantly decreased extent of Fe(II)-catalyzed transformation caused by associated OM. The organic compounds abundant in oxygen with high unsaturation were more preferentially associated with ferrihydrite than those with poor oxygen and low unsaturation; thus, the associated OM was capable of binding with 28.1-45.4% of reactive iodine. At comparable C/Fe ratios, the mobilization of iodine and aromatic organic compounds was more susceptible in the adsorption complexes compared to the coprecipitates. These new findings contribute to a deeper understanding of iodine cycling that is controlled by Fe-OM associations in anaerobic environments.