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Reusability and photocatalytic activity of bismuth-TiO2 nanocomposites for industrial wastewater treatment
摘要： In this study, bismuth-TiO2 nanotube (Bi-TNT) composites were used for the treatment of industrial wastewater. Bi-TNT were synthesized using two- and one-step anodization methods. The obtained composites were analyzed using X-ray diffraction, field emission scanning electron microscopy, UV–visible diffuse reflectance spectroscopy, Energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. For the two-step Bi-TNT composites, we investigated the effect of different Bi deposition times, Bi concentrations, and Bi deposition voltages on photodegradation efficiency. For the one-step Bi-TNT composites, we investigated the effect of different anodization voltages, anodization times, and Bi concentrations. Initially, the optimal synthesis conditions for two- and one-step Bi-TNT catalysts were identified and then these optimized conditions were used for industrial wastewater treatment that was collected from Banwol Sihwa Industrial Complex Republic of Korea. The Bi-TNT two- and one-step composites showed 2.0 and 2.5 times higher photocatalytic activity, respectively, for industrial wastewater treatment than that of TNT in visible-light. Recycling of Bi-TNT composites showed that the one-step composite method was more efficient and stable than the two-step method because Bi coupling and nanotube formation simultaneously occurred.
关键词： Recycling,Two- and one-step methods,Visible-light,Pollutant degradation,Bi-TiO2 composite
更新于2025-11-21 11:01:37
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Enzyme-free fluorometric assay for chloramphenicol based on double stirring bar-assisted dual signal amplification
摘要： An enzyme-free fluorometric assay is described that accomplishes dual signal amplification by making use of a two stirring bars. Two Y-shaped DNA probes were designed and placed on the bars. When the target (with chloramphenicol as model analyte) is added, it triggers target recycling and simultaneously catalyzes hairpin assembly (CHA). A large fraction of DNA primers is released by the analyte from the bar to the supernatant and open hairpins with G-quadruplex DNA sequence. The G-quadruplex can specifically bind thioflavin T (ThT) to emit fluorescence (with excitation/emission maxima at 445 and 485 nm) for quantification of chloramphenicol. An enzyme is not needed. ThT is added to the system as a fluorescent DNA probe. All this strongly reduces the cost for sensor construction and usage. The dual signal amplification steps occur simultaneously which reduces the detection time. The assay was successfully employed to the determination of CAP in spiked milk and fish samples within 60 min and with a 16 pM limit of detection (at S/N = 3).
关键词： Food safety,Antibiotics detection,Thioflavin T,Catalyzed hairpin assembly,Target recycling
更新于2025-11-19 16:46:39
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Zero background and triple-signal amplified fluorescence aptasensor for antibiotics detection in foods
摘要： It's important to eliminate matrix interference for accurate detecting antibiotic residues in complex food samples. In this study, we designed a zero-backgrounded fluorescence aptasensor to achieve on-site detection of antibiotic residues, with chloramphenicol (CAP) as representative analyte. Moreover, a three stir-bars assisted target recycling system (TSBTR) was designed to achieve triple signal amplification and increase the sensitivity. The bars included one magnetic stir-bar modified with two kinds of long DNA chains, and two gold stir-bars modified with Y shape-duplex DNA probes respectively. In the presence of CAP, the target could recurrently react with the probes on the bars and replace a large amount of long DNA chains into supernatant. After then, the bars were taken out and SYBR green dye was added to the solution. The dye can specifically intercalate into the duplex structures of DNA chains to emit fluorescence while not emitting a signal in its free state. Under the optimized experimental conditions, a wide linear response range of 5 orders of magnitude from 0.001 ng mL?1 to 10 ng mL?1 was achieved with a detection limit of 0.033 pg mL?1 CAP. The assay was successfully employed to detect CAP in food samples (milk & fish) with consistent results with ELISA's. High selectivity and sensitivity were attributed to the zero background signal and triple signal-amplification strategy. Moreover, the detection time can be shortened to 40 min due to that three signal amplified process can occur simultaneously. The fluorescent aptasensor was also label- and enzyme-free. All these ensure the platform to be rapid, cost-effective, easily-used, and is especially appropriate for detection antibiotics in food safety.
关键词： Three stir-bars assisted target recycling,Triple signal amplification,Zero background signal,Fluorescence aptasensor,Antibiotics
更新于2025-11-19 16:46:39
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High Quantum Yield Single-Band Green Upconversion in La <sub/>2</sub> O <sub/>3</sub> :Yb <sup>3+</sup> , Ho <sup>3+</sup> Microcrystals for Anticounterfeiting and Plastic Recycling
摘要： Single-band green upconversion (UC) with high green purity and color stability is urgently required for plastic recycling and anticounterfeiting. However, it is very difficult to obtain single-band green emission for benchmark Yb3+/Er3+ activated UC materials (such as NaYF4:Yb3+,Er3+) due to the strong accompanying red UC. Herein, highly efficient and stable single-band green UC is reported in La2O3:Yb3+/Ho3+ (LYH) microcrystals with record high absolute UC quantum yield (UCQY) of 2.6% for single-band green UC. LYH yields pure green UC with large and stable intensity ratio, IGreen/IRed ≈ 18. LYH presents not only higher UCQY for a single-band green UC but also much more pure and stable green UC than the benchmark UC materials such as NaYF4:Yb3+,Er3+ and Gd2O2S:Yb3+,Er3+. These results suggest that the newly developed LYH can, in principle, be promising for anticounterfeiting and plastic recycling. Its proof-of-concept is demonstrated as a security label based on a transparent institute logo.
关键词： anticounterfeiting,high UC quantum yield,plastic recycling,upconversion materials,pure green UC
更新于2025-09-23 15:23:52
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Building a Fluorescent Aptasensor Based on Exonuclease-Assisted Target Recycling Strategy for One-Step Detection of T-2 Toxin
摘要： In this work, a rapid and accurate assay was successfully developed for T-2 toxin detection based on exonuclease-catalyzed target recycling strategy. Upconversion nanoparticles (UCNPs) were conjugated with T-2 aptamer and used as signal probes, while magnetic nanoparticles (MNPs) were conjugated with the complementary DNA of T-2 aptamer (cDNA) and used as capture probes. The results reveled that good linear correlation (R2 = 0.9988) was achieved for T-2 toxin detection over the concentration range of 0.1–100 ng/mL with a detection limit as low as 0.035 ng/mL (S/N = 3). In addition, the reliability of the proposed method was also applied to the determination of T-2 toxin contents in real food samples and the average recoveries ranged from 95.97 to 104.00%. The sensing platform developed in our study demonstrated great potential for simple and sensitive detection of T-2 toxin contents in food samples.
关键词： T-2 toxin,Food safety,Fluorescence,Aptasensor,Target recycling strategy
更新于2025-09-23 15:23:52
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Power- and Spectral-Dependent Photon-Recycling Effects in a Double-Junction Gallium Arsenide Photodiode
摘要： Photon recycling effects improve radiative efficiencies of semiconductor materials, and play important roles in the design of high performance optoelectronic devices. Conventional research mostly studies the impact of photon recycling on the voltage of photodiodes. Here we systematically analyze the photon response of a microscale gallium arsenide (GaAs) based double junction photodiode. In such a device, the current matching condition between two subcells is determined by their photon coupling. Photodynamics in the device is examined and reveals the material’s internal quantum efficiencies. By leveraging photon distributions inside the device, we discover that its photocurrent and spectral responses are highly dependent on the illumination intensity. Consistent with theoretical analyses, the device’s photocurrents exhibit linear and superlinear power dependent characteristics under near-infrared and violet-blue illuminations, respectively. Due to strongly enhanced photon recycling effects under strong illumination, broadband photon responses (external quantum efficiency close to 50% from 400 nm to 800 nm) could be achieved in such a strongly current mismatched GaAs dual junction device. The understanding of photon processes in such devices would offer routes to the design of high-performance photodetectors and solar cells.
关键词： photovoltaics,photodetectors,gallium arsenide,photon recycling,multijunction
更新于2025-09-23 15:23:52
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Circular economy in RFID technology: analysis of recycling methods of RFID tags
摘要： Circular Economy (CE) is one of the approaches which are intensively developed and tested in different areas of industry and services. The aim of this solution is to use many kinds of resources in a closed flow and to achieve as a small amount of waste as it is possible. One of the potential areas of using CE is Radio Frequency Identification (RFID). In RFID systems tags are utilized in various forms. This paper addresses investigation of a recycling process of RFID tags. Different attachment methods of these tags were tested and then, a recycling procedure was prepared based on the obtained results in which adhesives are recommended to be used as an attaching material between a tag and an identified object. The mentioned procedure was evaluated with using paper-face RFID tags. It was confirmed applicability of the proposed solution. Moreover, the conducted research revealed that an adhesion force of the adhesive layers in the prepared RFID tags decreased in the most extent during the first recycling cycle. It was found that in order to preserve a high adhesion force of these layers it is suggested to place the tags on a clean surface.
关键词： Zero waste economy,mechanical force measurements,radio frequency identification,multiuse RFID tags,recycling cycle
更新于2025-09-23 15:23:52
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Hydrothermal synthesis of tellurium nanorods by using recovered tellurium from waste electronic devices
摘要： Tellurium (Te) nanostructures with controlled morphology have received considerable attention in various applications owing to tunable optic, thermoelectric, photoelectronic, piezoelectric, and electrochemical properties. Herein, we introduce the cost-effective and eco-friendly synthesis of Te nanorods (Te NRs) from end of life electronic devices via hydrothermal methods. The Te NRs show the average diameter of 44.6 nm and a length of 358 nm in presence of polyvinylpyrrolidone, as a stabilizing agent. Moreover, the bismuth and intact p-type semiconductor (i.e., Bi0.5Sb1.5Te3) are selectively recovered as intermediated products. The Te NRs exhibit the NO2 gas sensing properties with concentration as low as 1 ppm at room temperature and fast response/recovery times of 1.59 and 2.10 s at 1 ppm, respectively. We believe that this powerful approach can be expanded to not only selective recovery of valuable materials but synthesis of various nanomaterials from waste electronic devices.
关键词： Recycling,Grain growth,Chemical properties,Powders: chemical preparation,Sensors
更新于2025-09-23 15:23:52
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Characterization of IN 625 recycled metal powder used for selective laser melting
摘要： Additive manufacturing of high-quality materials by Selective Laser Melting depends not only on establishing appropriate process parameters, but also on the characteristics of the metal powders used and their stability over time or after recycling. The aim of the research was to characterize the IN 625 powder used over multiple manufacturing cycles with a Lasertec 30 SLM machine. In order to achieve the research’s goal, virgin and recirculated powder’s physical and technological characteristics were investigated. A decrease in all D-values (D10, D50, D90) of the powder size distribution was observed after multiple recirculation cycles showing a decrease of the powder dimensional range over time. Both virgin and recirculated powders are composed of mainly spherical particles, but elongated particles and satellite particles were observed as well. The dimensional evolution analysis showed a deviation from the powder ideal roundness, deviation that is more pronounced over multiple recirculation cycles. It was experimentally determined that the powders present a good ?owability based on the ?ow rate value obtained for both virgin and recirculated powders, con?rmed also by the Hausner ratio and angle of repose.
关键词： metallic powder,additive manufacturing,recycling,SLM,IN 625
更新于2025-09-23 15:21:01
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[IEEE 2020 IEEE 17th Annual Consumer Communications & Networking Conference (CCNC) - Las Vegas, NV, USA (2020.1.10-2020.1.13)] 2020 IEEE 17th Annual Consumer Communications & Networking Conference (CCNC) - On Performance of Underwater Wireless Optical Communications Under Turbulence
摘要： This paper considers a full-duplex (FD) point-to-point system consisting of one multi-antenna FD access point (FD-AP) and one two-antenna FD mobile station (FD-MS). We adopt simultaneous wireless information and power transfer scheme and apply the self-energy recycling at FD-MS. In order to minimize the weighted sum transmit power, we jointly design the transmit beamforming vector of FD-AP, the receive power splitting ratio of FD-MS, and the transmit power value of FD-MS. Since the original problem is non-convex, we apply semidefinite relaxation and obtain a new convex problem. We further prove that both problems have exactly the same solutions. Finally, simulations are provided to verify our analysis, and the comparison with a half-duplex system demonstrates the significant performance gain from self-energy recycling.
关键词： SWIPT,SDR,Full-duplex,optimality,self-energy recycling
更新于2025-09-23 15:21:01