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Electrochromic Properties of Polyaniline-Based Hybrid Organic/Inorganic Materials
摘要： Hybrid materials based on polyaniline (PAni) were obtained by in situ polymerization of aniline with chitosan and/or organically modified clay (nanomer I-24) in HCl. The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and direct current (DC) electrical conductivity. Thin films of PAni, PAni-clay, PAni-chitosan and PAni-chitosan-clay were prepared by casting a solution of each sample in N-methyl-2-pyrrolidone (NMP) onto indium tin oxide (ITO)/glass electrodes and their electrochromic properties were investigated. It was observed color variation from transparent yellow in the reduced state (E = ?0.2 V vs. Ag/AgCl), green in the intermediate state (E = 0.5 V) and dark blue in the oxidized state (E = 0.8 V) for all samples. The color changes of each material in function of the applied potential were tracked using the Commission Internationale de l’Eclairage (CIE) system of colorimetry, in which the color change was much more significant for PAni-clay film.
关键词： chitosan,organophilic clay,hybrid material,conjugated polymer,polyaniline
更新于2025-09-23 15:22:29
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Synthesis and characterization of spin-coated clay/PVDF thin films
摘要： This paper reports the fabrication of Cloisite-15A (C-15A)-dispersed polyvinylidene fluoride (PVDF) nanocomposite thin films by spin coating and their characterization for sensor applications. The effects of nanoclay, duration of ultrasonication and spinning speed on the morphology and properties of thin films were studied. The influence of these parameters on the amount of β-phase was analysed using Fourier transform infrared (FTIR) and X-ray diffraction (XRD) techniques. The influence of C-15A on the morphology and surface quality of thin films was analysed by scanning electron microscopy (SEM). Piezoelectric coefficient was measured at 110 Hz and 0.25 N. Contact angle was measured to assess the hydrophobicity of thin films. The β-phase of 82.97% was obtained in the specimens with 5 wt% C-15A, processed at 500 rpm and spun for 35 min. The piezoelectricity of the specimens increased from ?18 to ?25 pC N?1. Experiments were conducted as per L16 orthogonal array.
关键词： spin coating,Cloisite-15A,β-crystals,PVDF/clay thin films,piezoelectricity
更新于2025-09-23 15:22:29
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Effects of different LED lights and substrate media on growth of lettuce in an aquaponic system
摘要： Light emitting diodes (LED) are a good source of light energy because its light intensity can be adjusted, it has a low operating temperature as well as a long life and it uses less energy than other light sources. Current agriculture production places increasing emphasis on producing clean food, conserving the environment and effectively utilizing energy. Lettuce (Lactuca sativa L. ‘Ziwei’) production in an aquaponic system, exploiting waste excreted by fish as the plant fertilizer, was investigated. LEDs of various colour combinations were used as light sources for growing lettuce; included 1) fluorescent (a non-LED control), 2) white LED, 3) white and red LED (1:1), 4) white and red LED (1:2), 5) white and red LED (2:1) and 6) white, red and blue LED (1:1:1). Plants were grown on two substrates (laterite rock and expanded clay balls) in flood and drain aquaponic systems. Lettuce grown under white and red LEDs light (1:1, 1:2 and 2:1) on the laterite rock had the greatest plant height, leaf length, leaf width, leaf number, SPAD value, fresh and dry weight of stem and roots without iron deficiency symptoms. The combination of white and red LEDs lights (1:1, 1:2 and 2:1) and laterite rock has potential to improve growth of vegetables grown on aquaponic systems in greenhouse and plant factories.
关键词： laterite rock,clay balls and plant factory
更新于2025-09-23 15:21:01
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Particle Size Distribution of Natural Clayey Soils: A Discussion on the Use of Laser Diffraction Analysis (LDA)
摘要： Particle size distribution is one of the most significant factors determining physical soil properties. Laser diffraction analysis (LDA) is an alternative method to the traditional hydrometric methods (HM) used to determine particle size distribution in soils. However, significant differences in fraction content are found in relation to the applied methods of a particle size test. Above all, measurements performed by LDA for clayey soils usually produce different results to those based on Stokes’ equation. Methodical problems, such as an appropriate method of dispersing the sample and the selection of LDA calculation theory, also play a significant role in fine soils. This paper contains the results of analyses of Neogene clays from Poland, which are characterized by differentiation with regard to the content of clay fraction particles. In this article, the validity of using laser diffraction analysis (LDA) for the identification and characterization of clayey sediments with common genesis is assessed. The possibility of finding reliable pedotransfer functions to the convert LDA results to a hydrometric analysis is discussed.
关键词： Stokes’ equation,clay soils,shape anisotropy,hydrometric method,particle size analysis,laser diffraction analysis (LDA)
更新于2025-09-23 15:19:57
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Soil Content Accurately Modeled Using Spectroscopy
摘要： Soil is the foundation of food production on the planet. Clay and organic carbon content of the soil are among the most influential factors in soil functions, productivity, and management. Current laboratory methods for studying clay and organic carbon are slow, highly uncertain, and expensive. Visible near-infrared spectroscopy has shown to be a powerful tool to detect and quantify molecules of interest in a sample. In an article recently published in the Soil Science Society of America Journal, researchers report on a novel method of combinatory on-the-go spectroscopy and soil electrical conductivity measurements in agricultural fields as a substitute to soil sample collection and laboratory analysis. The team used multivariate regression methods to predict soil clay and organic carbon in soil using the rapidly obtained data. They found that although the uncontrolled spectral measurement environment in the field introduced a large amount of noise in the dataset, comprehensive spectral preprocessing and redundant variable removal could still lead to accurate models. Furthermore, it was shown that spectroscopy alone could provide the best results without the need for adding electrical conductivity data. In addition to the practical applications in soil and agricultural studies, the results also have important implications for future sensor design, data processing, and soil modeling.
关键词： soil content,organic carbon,multivariate regression,spectroscopy,clay
更新于2025-09-16 10:30:52
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Feasibility of Plasma Treated Clay in Clay/Polymer Nanocomposites Powders for use Laser Sintering (LS)
摘要： The addition of small quantities of nano-clay to nylon is known to improve mechanical properties of the resulting nano-composite. However, achieving a uniform dispersion and distribution of the clay within the base polymer can prove difficult. A demonstration of the fabrication and characterization of plasma-treated organoclay/Nylon12 nanocomposite was carried out with the aim of achieving better dispersion of clay platelets on the Nylon12 particle surface. Air-plasma etching was used to enhance the compatibility between clays and polymers to ensure a uniform clay dispersion in composite powders. Downward heat sintering (DHS) in a hot press is used to process neat and composite powders into tensile and XRD specimens. Morphological studies using Low Voltage Scanning Electron Microscopy (LV-SEM) were undertaken to characterize the fracture surfaces and clay dispersion in powders and final composite specimens. Thermogravimetric analysis (TGA) testing performed that the etched clay (EC) is more stable than the nonetched clay (NEC), even at higher temperatures. The influence of the clay ratio and the clay plasma treatment process on the mechanical properties of the nano-composites was studied by tensile testing. The composite fabricated from (3% EC/N12) powder showed ~19 % improvement in elastic modulus while the composite made from (3% NEC/N12) powder was improved by only 14%). Most notably however is that the variation between tests is strongly reduced when etch clay is used in the composite. We attribute this to a more uniform distribution and better dispersion of the plasma treated clay within polymer powders and ultimately the composite.
关键词： Clay/Polymer Nanocomposites,Mechanical Properties,Plasma Treated Clay,Laser Sintering,Nylon12
更新于2025-09-12 10:27:22
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Modification of kaolinite from Pará/Brazil region applied in the anionic dye photocatalytic discoloration
摘要： The incorporation of titanium oxide and other transition metals on the surface of different materials has been shown to be a promising strategy to improve the efficiency of photocatalytic processes aiming at the decontamination of aqueous systems caused by persistent organic contaminants such as dyes. The objective of this work was to evaluate the catalytic properties of nanocomposites based on the kaolinite (Kaol) with TiO2 incorporated, obtained from the sol-gel method, used in discoloration of the coomasie brilliant blue dye (CBB) in aqueous solution. The nanocomposites were prepared from the reaction of titanium tetraisopropoxide with purified natural kaolinite and calcined at different temperatures. The samples were characterized by the XRD, FTIR, SEM-XED, BET-BJH and diffuse reflectance spectroscopy techniques, which demonstrated the structure, crystalline pattern, as well as the incorporation of titanium in the clay structure, changes caused by modification in morphology, texture and energy gap. The photocatalytic tests were performed using 5 × 10?5 mol L?1, 1.0 and 1.5 g L?1 concentration, respectively, to the CBB dye solution and to the synthesized materials. Among the nanocomposites, the sample calcined at 300 °C, KaolBT-300, presented the best photocatalytic performance. The addition of the H2O2 oxidant to the solution containing KaolBT-300 at the concentration of 1.5 g L?1 increased the discoloration percentage to 97.31% of the CBB solution dye after 120 min of irradiation. The discoloration kinetics of the CBB dye obeys the pseudo-first-order velocity law. Finally, the reuse of the KaolBT-300 sample in three consecutive cycles of photocatalysis demonstrated a significant adhesion stability of the TiO2 particles on the clay surface, indicating that it can be used in advanced oxidative processes for the degradation of organic pollutants.
关键词： Natural clay,Sol-gel synthesis,Heterogeneous catalysis,Titanium oxide,Water treatment,Dye
更新于2025-09-10 09:29:36
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An affordable photocatalyst for pharmaceuticals and superior electro catalyst for methanol oxidation - A dual role by CuWO4 anchored bentonite clay
摘要： In this present study, we developed a novel bentonite loaded CuWO4 nanoparticles (BEN-CuWO4 NPs) through the simple hydrothermal method. The as-prepared BEN-CuWO4 NPs was systematically characterized by various spectroscopic techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Field emission scanning electron microscopy (FESEM), High resolution transmission electron microscopy (HR-TEM), DRS-UV visible spectroscopy, Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS) and Photoluminescence (PL) techniques. For the first time, the BEN-CuWO4 NPs were utilized as a bifunctional catalyst for the photodegradation of Diclofenac sodium (DFS) and electrooxidation of methanol. More distinctively, the BEN-CuWO4 NPs exhibited excellent photocatalytic activity could degrades above 94% DFS solution under visible light illumination with superior stability. Further, BEN-CuWO4 NPs portrayed superior electrocatalytic activity for the oxidation of methanol when compared to the pristine CuWO4. In addition, Impedance studies revealed that the BEN-CuWO4 NPs holds the tremendous dielectrical properties. This present investigation opens a new door way for the synthesis of multifunctional nanostructured materials for practical energy and environmental applications.
关键词： Photo degradation,Electrochemical studies,Bentonite clay,Copper tungstate,Hydrothermal,Diclofenac sodium
更新于2025-09-10 09:29:36
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Applications of sunlight responsive Fe-Ag-TiO2 composite incorporating in-situ dual effect for the degradation of pentoxifylline
摘要： Silver modified TiO2 based immobilized system incorporating in-situ dual effect (photocatalysis and photo-Fenton) was examined for the degradation and mineralization of an environmentally persistent drug, pentoxifylline (PEN) under natural sunlight. The modified TiO2 was characterized through DRS, XRD, SEM/EDS, TGA, XPS, FTIR, and Raman spectroscopy to confirm the distribution of Ag on TiO2 surface. Ag-TiO2-P25 exhibited better degradation efficiency with high rate constant i.e. 0.055 min?1 in comparison to 0.037 min?1 (unmodified TiO2-P25). Attempts were made to enhance the degradation efficiency of system by incorporating in-situ dual effect in fixed-mode using Ag-TiO2-P25. Novel clay beads using waste fly-ash and foundry sand were used for Ag-TiO2-P25 immobilization (Fe-Ag-TiO2 composite). The value of rate constant was augmented to 0.132 min?1 with dual process. The practical feasibility of technique was validated by conducting the degradation of PEN in a solar pilot-scale reactor with total volume handling of 5 L using Fe-Ag-TiO2 composite.
关键词： Clay beads,Dual effect,Ag-TiO2-P25,Fe-Ag-TiO2 composite
更新于2025-09-10 09:29:36
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Effect of Calcination Temperature in Preparation of ZnO-SiO2/Laponite and its Physical Character and Photocatalytic Activity
摘要： ZnO-SiO2/laponite was prepared by sol-gel preparation procedure consit of SiO2 pillarization to laponite followed by ZnO dispersion by using zinc acetate as precursor. The obtained material was characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, diffuse reflectance UV-visible (DRUV-visible) and N2 adsorption-desorption analysis. The photocatalytic performance of the material in decolorization of methylene blue was also investigated. Compared with ZnO-SiO2 nanoparticles, it is concluded that ZnO-SiO2/laponite possess higher photocatalytic activity and influenced by calcination temperature.
关键词： Photocatalyst,Pillarization,Laponite,Clay,ZnO-SiO2
更新于2025-09-09 09:28:46