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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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Citrus limetta Organic Waste Recycled Carbon Nanolights: Photo-electro catalytic, Sensing and Biomedical Applications
摘要： The present work reports green route-waste recycled carbon nanolights i.e. carbon dots (GCDs) synthesized via a facile one-step pyrolysis method from Citrus limetta waste pulp. The size of these obtained pristine GCDs is ~4-7 nm (HR-TEM), with high optical and structural quality as revealed by FT-IR and Raman spectroscopic analysis. They exhibit the highest quantum yield of 63.3 % over other similar green synthesized GCDs, favourable for many applications. Further, we demonstrate the multifunctional aspects of these synthesized GCDs for photo-electrochemical water splitting, photocatalytic methylene blue degradation, Fe(III) ions sensing, bactericidal activity (against E. coli and S. aureus), and bioimaging with excellent performance. The visible light active characteristic of GCDs is observed to achieve an efficient current density of ~6 mA/cm2 towards water splitting. This study demonstrates the waste to wealth potential of recycled waste derived GCDs in wide range of application domains.
关键词： GCDs,Biomedical,Green Synthesis,Waste Recycle,Dye Degradation,Water Splitting
更新于2025-09-23 15:21:01
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Recycling of light-emitting diode waste quartz sand as a pozzolanic material
摘要： LED waste quartz sand (LEDWS), which is a prominent byproduct of the LED manufacturing process, may contaminate the environment because it comprises numerous nanoparticles of SiO2, Al2O3, and SiC, which are hazardous ingredients that are harmful to the environment and human health when disposed of improperly. Therefore, this study investigated the pozzolanic reaction behavior of these industrial byproducts to obtain a valuable processing method for LEDWS in cement. The results showed that with increased curing time, the strength of the pastes that incorporated 10% LEDWS approached that of ordinary Portland cement. A stretching broad band was centered at 1074e1081 cm-1 from chemically bound H2O in the hydrated calcium silicate (CeSeH). Thus, the correlation between the hydration degree of the paste that incorporated LEDWS and compressive strength evolution is crucial. The results implied that LEDWS can be used as a partial replacement source for cement applications; thus, LEDWS can be used as pozzolanic material.
关键词： Degree of hydration,Calcium silicate,Recycle,Light-emitting diode waste quartz sand,Pozzolanic reaction
更新于2025-09-23 15:19:57
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Study on the optimal deployment for Photovoltaic components recycle in China
摘要： Photovoltaic (PV) production and installation surge in recent years because of technology development and policy orientation. However, due the deadlines of subsidy set by Chinese government, most of the PV projects are carried out in a hurry and quality issues appear. Some equipment turn out to be inferiors. The demand for subsequent treatment for PV components will surge in the early future. However, the insufficiency of recycle facilities and supporting policies, lack of public focus, make it difficult. For a better planning of PV recycle, an optimization model is applied to study on the optimal deployment of PV recycle centers in China during 2040 to 2045 based on cost minimization. Transportation cost for PV modules, capital cost and operational cost for recycle center in different provinces are taken into consideration of objective functions. The result indicates that the peak of PV components recycle will arrive around 2042. At the early stage, recycle centers will be established in Zhejiang, Guangdong, and Shanxi province, considering the intensive installation and convenient transportation. The discarded PV panels will be transported to those provinces. Then, as the recycle demand surging, recycle centers will be scattered in many provinces, such as Jiangsu, Ningxia, Hebei, Inner Mongolia and so on. Most of the PV components will be recycled within the installed provinces.
关键词： recycle modes,Photovoltailc module,recycle center deployment,recycle standards
更新于2025-09-12 10:27:22
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Mn doped ZnO nano material: a highly visible light active photocatalyst for environmental abatment
摘要： Mn doped ZnO nano photocatalyst (MnDZ) was prepared via simple co-precipitation method. MnDZ catalyst was characterized by XRD, FT-IR, UV–Vis-DRS, FE-SEM and TEM. The FE-SEM images showed that the MnDZ have rod and sphere like morphology with a size ranged from 20 to 50 nm. The catalytic activities were tested for the degradation of Direct blue 71 under visible light irradiation. The catalyst found to be highly active under neutral pH range and exhibit pseudo-first-order kinetics. The reusability of the photocatalyst indicates that 93% of dye was degraded even upto 3rd cycles of use.
关键词： ZnO,recycle,manganese,visible light,photocatalyst
更新于2025-09-10 09:29:36