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Separation of boron from silicon by steam-added electron beam melting
摘要： Removal of boron from silicon is a tough task by traditional directional solidification and vacuum refining techniques, due to its large and inappropriate segregation coefficient and low saturated vapor pressure. At high temperature boron react with oxygen to form volatile boron oxides which can be evaporated. So, the removal procedure of boron from silicon melt is investigated by incorporating a small amount of water vapor above the melted surface. The results show that boron is oxidized to mainly form BO and evaporated with 28% removal efficiency by average. It is considered that oxygen atoms experience a series of physical and chemical processes, such as a chemical reaction in the bulk of the melt, evaporation from the melt surface, transportation across the gas phase and ionization due the electron beam, which is conducive to the continuous removal of boron.
关键词： Electron beam melting,Photovoltaic,Boron removal,Oxygen self-circulating path,Solar-grade silicon
更新于2025-09-23 15:23:52
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Q-graphene-scaffolded covalent organic frameworks as fluorescent probes and sorbents for the fluorimetry and removal of copper ions
摘要： Metal-free fluorescent covalent organic frameworks (COFs) were synthesized initially with Q-Graphene (QG) scaffolds by the one-step covalent reactions of melamine-aldehyde and phenol-aldehyde poly-condensations using paraformaldehyde. It was discovered that onion-like hollow QG, which consists of multi-layer graphene and different carbon allotropes having a high proportion of folded edges and surface defects, could endow the scaffolded COFs with enhanced green fluorescence and environmental stability. Unexpectedly, they could exhibit the powerful absorption for Cu2+ ions resulting in the specific quenching of fluorescence. A fluorimetric strategy with QG-scaffolded COFs was thereby developed to probe Cu2+ ions separately in blood and wastewater with the linear concentration ranges of 0.0010 - 10.0 μM (limit of detection of 0.50 nM) and 0.0032 - 32.0 μM (limit of detection of 2.4 nM), respectively, promising the potential applications for the field-applicable monitoring of Cu2+ ions in the clinical and environmental analysis fields. In addition, the prepared COFs sorbents were employed to absorb Cu2+ ions in wastewater showing high removal efficiency. More importantly, such an one-pot fabrication route with hollow QG scaffolds may be tailorable extensively for the preparation of a variety of metal-free multifunctional COFs with enhanced fluorescence, water solubility, environmental stability, and metal removal capability.
关键词： Q-Graphene Scaffold；Covalent Organic Frameworks；Fluorescent Analysis；Removal Sorbents；Copper Ions
更新于2025-09-23 15:23:52
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Photocatalysis removing of NO based on modified carbon nitride: The effect of celestite mineral particles
摘要： Atmospheric NO is one of the toxic and hazardous gases. Its’ levels are continually rising in recent years. As we known, mineral particles contained in the atmosphere may affect the photocatalytic NO removal process. In this study, we found that celestite modification could greatly improve the activity (about 3.8 times) and stability of g-C3N4 for the photocatalytic NO removal. In our system, celestite particles embed in the N vacancies of g-C3N4. The synergistic effect of celestite and N vacancy is the origin of improved NO removal activity. During the light irradiation, photogenerated electrons can be captured and confined by N vacancy. Meanwhile, celestite can transfer these confined electrons to O2 and produce more ·OH, which could oxidize NO to nitrate. These findings can help us to understand the influence of mineral particles in the photocatalytic NO removal and design highly efficient NO removal phtocatalysts.
关键词： NO removal,g-C3N4,Photocatalysis,Celestite,Mineral particles
更新于2025-09-23 15:23:52
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Enhanced oxytetracycline removal coupling with increased power generation using a self-sustained photo-bioelectrochemical fuel cell
摘要： Photo-bioelectrochemical fuel cell (PBFC) represents a promising technology for enhancing removal of antibiotic pollutants while simultaneously sustainable transformation of organic wastes and solar energy into electricity. In this study, simultaneous antibiotic removal and bioelectricity generation were investigated in a PBFC with daily light/dark cycle using oxytetracycline (OTC) as a model compound of antibiotic. The specific OTC removal rate increased by 61% at an external resistance of 50 U compared to that in the open-circuit control, which was attributed to bioelectrochemically enhanced co-metabolic degradation in the presence of the bioanode. The OTC removal was obviously accelerated during illumination of cathode in contrast with a dark cathode due to the higher driving force for anodic bioelectrochemical reaction by using photosynthetic oxygen as cathodic electron acceptor during illumination than that using nitrate in dark. The bioelectrocatalytic activity of anodic biofilm was continuously enhanced even at an initial OTC concentration of up to 50 mg L?1. The degradation products of OTC can function as mediators to facilitate the electron transfer from bacteria to the anode, resulting in 1.2, 1.76 and 1.8 fold increase in maximum power output when 10, 30 and 50 mg L?1 OTC was fed to the bioanode, compared to the OTC-free bioanode, respectively. The OTC feeding selective enriched OTC-tolerant bacterial community capable of degrading complex organic compounds and producing electricity. The occurrence of ARGs during bioelectrochemical degradation of OTC was affected more greatly by the succession of the anodic bacterial community than the initial OTC concentration.
关键词： Bioanode,Electron transfer,Oxytetracycline removal,Photo-bioelectrochemical fuel cell
更新于2025-09-23 15:23:52
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Purification and comprehensive utilization of sapphire kerf waste
摘要： Sapphire kerf waste (a fine powder) is a great potential source of high-purity α-Al2O3 and is currently discarded without reutilization, which is a waste of this resource and causes environmental problems, such as occupying space and generating dust. Herein, we report a feasible combined method to recycle valuable high-purity α-Al2O3 from sapphire kerf waste through the ultrasound-assisted leaching of nickel, diamond removal by bulk heating and a grinding process. The impurities in the waste were collected, and their existence states were characterized as independent metal nickel and diamond. The nickel impurity was removed from the waste by ultrasound-assisted leaching using a mixture of sulfuric acid and nitric acid, and the optimal leaching efficiency reached 99.67% under the conditions of sulfuric acid: nitric acid = 2:1 (v/v), 4 mol/L H+ concentration, 4 mL/g liquid-solid ratio, 45 °C, 30 min, 200 rpm, 240 W ultrasonic power and 45 kHz ultrasonic frequency. Subsequently, nickel ions in the lixivium were recycled in the form of nickel sulfate through extraction and stripping treatments. The diamond impurity was removed by bulk heating in flowing oxygen, and the optimal removal ratio was 99.65% under the conditions of 800 °C, 30 min and oxygen flow of 400 mL/min. High-purity α-Al2O3 was successfully recovered from the sapphire kerf waste after the grinding process, which had a purity higher than 99.99 wt% and an average diameter of 0.6 mm. In addition, the kinetics of leaching nickel and diamond removal were systematically analysed based on the shrinking model, and the chemical reaction was found to be the control step. The reaction mechanisms of the two processes were also studied. The economic evaluation revealed that the profit from dealing with 1 kg sapphire kerf waste with this method was $13.68. Therefore, the proposed method is promising for providing technical and economical guidance for industrial production.
关键词： Purification,Sapphire kerf waste,Carbon removal,Nickel leaching,Recycle
更新于2025-09-23 15:23:52
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Color removal from wastewater by photocatalytic process using titanium dioxide-coated glass, ceramic tile, and stainless steel sheets
摘要： Dye pollutants from textile industries are a major wastewater problem because they have complex chemical structures. Photocatalysis is a promising wastewater treatment method, which is used to remove dyes under light irradiation in the presence of a photocatalyst. In this article, titanium dioxide (TiO2) photocatalyst was synthesized through sol-gel technique and coated on different substrates (i.e. transparent glass, glazed ceramic tile, and stainless steel) by doctor blade technique. The coated substrates were used in an innovative reactor to remove colors in dye wastewater. The photocatalytic activities of the designed reactor were determined using a synthetic dye wastewater (methylene blue) under UV irradiations (36W-UVA or 30W-UVC lamps). The results showed that the optimum substrate yielded the highest color removal efficiency (93.03 ± 0.66%) was TiO2-coated glass under UVC irradiation. The recycling ability of TiO2-coated glass sheet was also evaluated. It was found that TiO2-coated glass sheet provided the same efficiencies for 20 cycles. In addition, the actual wastewater from textile industry was tested in this study with different pH values (i.e. pH = 3e11). The maximum color removal obtained was 87.86 ± 0.23% at pH value 11 on TiO2-coated glass under UVC irradiation. The color removal was found to decrease with decreasing pH.
关键词： Photocatalysis,Color removal,Wastewater treatment,Titanium dioxide,Dye wastewater
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 8th International Conference on Consumer Electronics - Berlin - Berlin, Germany (2018.9.2-2018.9.5)] 2018 IEEE 8th International Conference on Consumer Electronics - Berlin (ICCE-Berlin) - Fast Rain Removal Using Rain Map and Temporal Filtering for Consumer Imaging Applications
摘要： This paper presents the severe weather image enhancement method using for consumer imaging systems. The proposed method performs the rain removal based on a rain map, which estimated by the difference among the adjacent frames. In the video frames, since the rain streaks can be regarded as the object moving in a constant direction, we can analyze the position of the rain streaks using the difference between the previous and next frames. In addition, we refine the rain map using the saturation channel in HSV color space and low-pass filtering. Experimental results show that the proposed method can provide better restored image at fast processing time compared with existing methods.
关键词： Deraining,Rain removal,Rain property
更新于2025-09-23 15:23:52
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The effect of cut depth and distribution for abrasives on wafer surface morphology in diamond wire sawing of PV polycrystalline silicon
摘要： Due to the existence of an acid etch resistant thin amorphous silicon layer over the smooth grooves of the diamond wire sawing polycrystalline silicon wafer surface, the anti-re?ection e?ect is usually not ideal using the mature acidic texturization. The amorphous silicon layer will be produced on the machined surface by material ductile removal. Therefore, during the process of cutting photovoltaic polycrystalline silicon wafers, the material removed in the brittle way is expected and the surface topography of the wafers formed with the brittle fracture is better for the texture fabricating. In this paper, a mathematical model considering the in?uences of process parameters and wire saw parameters was developed based on indentation fracture mechanics. The variations of cutting groove pro?le formed by di?erent material removal modes were also included. The e?ect of abrasives distributed on the wire saw on material removal and surface formation of polysilicon was analyzed. The results showed that most of abrasives removed material with ductile removal mode, however, the volume of the material removed by abrasive in ductile mode is less than 10% of the total removal volume. Brittle fracture removal mode was still the major way of material removal in diamond wire sawing. With the same ratio of the feed rate and wire speed, the faster feed rate and wire speed will not only improve the cutting e?ciency, but also is easier to obtain a brittle fracture surface. There is a critical angle θc for the distribution of abrasives on the wire saw surface. Only when the position angle of the abrasive removing material in brittle mode is less than θc, the brittle fracture can be formed on the wafers surface.
关键词： Diamond wire sawing,Depth of cut,Material removal mode,Photovoltaic polycrystalline silicon
更新于2025-09-23 15:23:52
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Boosting Visible-light-driven Photooxidation of BiOCl by Promoted Charge Separation via Vacancy Engineering
摘要： The separation of electron-hole pairs has an important influence on the photocatalytic process on semiconductors. In this work, BiOCl nanosheets with oxygen vacancies (BiOCl-OVs) have been prepared by reconstructing small hydrophobic BiOCl nanosheets. The transient photoresponse and the electron spin resonance (ESR) results prove that the separation of the charge carriers can be promoted by the oxygen vacancies via trapping the photoexcited electrons. Due to the improved charge separation and wide absorption of the solar spectrum, more photogenerated charge carriers are produced, as confirmed by the photocurrent response and the ESR measurements of the reactive oxygen species ?O2- and ?OH. Consequently, BiOCl-OVs present enhanced photocatalytic properties towards NO removal. Our study illustrates the importance of the construction of vacancies for improving photocatalytic performance.
关键词： oxygen vacancies,charge separation,BiOCl,NO removal,photocatalytic
更新于2025-09-23 15:23:52
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Removal of Polymers for KrF and ArF Photoresist Using Hydrogen Radicals Containing a Small Amount of Oxidizing Radicals
摘要： Photoresist removal method using hydrogen radicals, which are produced on a tungsten hot-wire catalyst, is effective to resolve some environmental and industrial problems in conventional methods for the fabrication of electronic devices. However, its removal rate is not as good as that of the conventional ones. We have previously described that the removal rate of a positive-tone novolac photoresist is enhanced by the addition of a small amount of oxygen gas to the atmosphere, in which hydrogen radicals are produced. Oxidizing radicals, such as OH and O radicals, can be produced together with H radicals. In present study, we examined the effects of oxygen addition on base polymers of KrF and ArF photoresists: the former is poly(vinyl phenol) (PVP), and the latter is poly(methyl methacrylate) (PMMA). Effects of oxygen addition on PVP was confirmed, as was found for the novolac photoresist. On the other hand, the effects on PMMA were different from the cases of the novolac photoresist and PVP. Results were ascribed to the presence or absence of benzene rings, the properties of polymers and the reactivity of oxidizing radicals.
关键词： Oxygen addition,Environment,Removal,Photoresist,Hydrogen radical
更新于2025-09-23 15:23:52