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Preparation of all-cellulose composites with optical transparency using the banana pseudostem as a raw material
摘要： Biopolymers are intended to substitute the petroleum-based polymers and all-cellulose composite has emerged as a green alternative, especially if it can be prepared through a method consuming less energy and fewer chemicals. Here, a novel approach to obtain a nanocomposite film made of cellulose fibrils imbibed into a nanocellulose matrix is described. Banana pseudostem was used as raw material and characterized along with the resulting materials using scanning electron microscopy, optical microscopy and Raman spectroscopy, while the cellulose/nanocellulose film was studied through X-ray diffraction, UV–Vis-NIR spectroscopy and laser scanning microscopy. Results indicate that cellulose (fibrils) and nanocellulose (platelets), extracted from banana pseudostem were successfully purified using hydrolysis at a relatively low amount of chemicals. Transparent films made of a fibrils/nanoplatelets blend were prepared by the solution casting method, exhibiting a transmittance of & 83–88% and a crystallinity index of & 70, hence demonstrating the feasibility of this novel method to obtain cellulose/nanocellulose free-standing films.
关键词： Nanocomposites,Cellulose nanoplatelets,Cellulose/nanocellulose films,Agricultural waste,Inner pseudostem
更新于2025-11-21 11:08:12
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E‐Waste Based V <sub/>2</sub> O <sub/>5</sub> /RGO/Pt Nanocomposite for Photocatalytic Degradation of Oxytetracycline
摘要： The increasing prevalence of antibiotics in the environment has promoted the development of antibiotic resistant microorganisms, and novel approaches are needed to effectively remove antibiotics from water and mitigate this worldwide problem. A reduced graphene oxide-V2O5 (RGOV) nanocomposite was synthesized and used for photocatalytic degradation of the antibiotic oxytetracycline (OTC) in aqueous solution. The Sol–Gel method was employed for V2O5 synthesis from e-waste-based vanadium nitrate, and a one pot solvothermal method was used to synthesize RGOV. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM) with energy dispersive analysis of X-rays (EDAX) confirmed V-O-C bonds on the surface of the RGOV nanocomposites. A decrease in the band gap of V2O5 from 2.21 to 2.13 eV was supported by diffuse reflectance ultraviolet–visible spectrophotometry. OTC adsorption onto the nanocomposite increased with an increase in RGO concentration and saturated at 17% for RGOV with 30% graphene oxide. The composite degraded 90% of the OTC present in aqueous solution (50 mg/L). Platinum (1%) doping further increased OTC degradation by the nanocomposite to 98.7%. Optimum conditions for maximum OTC degradation are (1) an initial OTC concentration of 50 mg/L, (2) a RGOV nanocomposite dose of 0.5 g/L, and (3) a 40 min incubation time. Our results support the potential use of RGOV nanocomposite for OTC photodegradation.
关键词： vanadium pentoxide,photocatalytic degradation,nanocomposite,E-waste,RGO,oxytetracycline
更新于2025-09-23 15:23:52
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Enhanced green photoluminescence of erbium doped Zn2SiO4 glass-ceramics as phosphor in optoelectronic devices
摘要： This paper reported the fabrication of Er3+-doped zinc silicate (Zn2SiO4:xEr3+) glass-ceramics using recycle waste glass bottles. The glass-ceramics samples were synthesized with different percentage doping of Er2O3 using conventional melting and quenching method. The structural of α-Zn2SiO4:Er3+ crystal phase and microstructure growth were analysed via X-ray diffraction and field emission scanning electron microscopy, respectively. Fourier transform infrared spectroscopy has confirmed the network structure of α-Zn2SiO4:Er3+ crystal phase. The three excited transition states from UV-visible absorption spectra were enhanced significantly at the states 4F7/2, 2H11/2, 4F9/2. The wide-ranging green emission at around 553-559 nm under excitation 385 nm from α-Zn2SiO4:Er3+ crystal exhibit the energy transition of Er3+ ions from 4S3/2 → 4I15/2. Such luminescence of α-Zn2SiO4:Er3+ based glass-ceramics are probably to have a huge prospective application for glass phosphor devices.
关键词： emission,phosphor,zinc silicate,waste glass,glass-ceramic
更新于2025-09-23 15:23:52
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Mitigating the electromagnetic radiation by coupling use of waste cathode-ray tube glass and graphene oxide on cement composites
摘要： With technological development, the rapid growing numbers of electronic devices generate severe electromagnetic interference (EMI) and radiation to human environment. In this study, the coupling effect of graphene oxide (GO) addition (up to 0.10 wt.% of cement) and waste cathode-ray tube (CRT) glass replacement for fine aggregates (30 and 60 wt.%) in cement-based composites on mitigating EMI was studied. The electric permittivity obtained using a decoupling method was applied for evaluating the EMI shielding capacity of cement-based composites, while direct current (DC) electrical resistance measurement is conducted using four-probe method. The DC electrical resistivity of specimens increases insignificantly with increasing in GO content, but remarkably with increasing CRT glass content from 30 to 60 wt.%. The 60 wt.% replacement of waste CRT glass with 0.1 wt.% GO addition increases the relative permittivity by about 50% and 200% when the frequency is in the ranges of 104–5 × 106 Hz and 101–103 Hz, respectively. It is concluded that a significant increase in the permittivity can be obtained owing to the synergetic interaction between waste CRT glass and GO. The improvement in the EMI shielding ability of cement-based composites not only enables the applications of these composites in mitigating electromagnetic pollution, but also promotes large-volume recycling of toxic waste CRT glass.
关键词： Permittivity,Waste CRT glass,Cement composite,Graphene oxide,Electromagnetic interference
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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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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[IEEE 2018 Applications of Electromagnetics in Modern Techniques and Medicine (PTZE) - Rac?awice (2018.9.9-2018.9.12)] 2018 Applications of Electromagnetics in Modern Techniques and Medicine (PTZE) - Attenuation of High Frequency Electromagnetic Waves by Polymer Composites with Waste Materials
摘要： Composite materials with polymers and waste materials like zinc ore, mill scale, and iron dust are studied with respect to attenuation of electromagnetic radiation of high frequency. Samples of such composites were prepared and tested for several frequencies in 8-12 GHz band. The composites relatively strongly attenuate electromagnetic radiation in the considered band. Using various waste materials has also ecological aspect.
关键词： electromagnetic radiation,high frequency,attenuation,polymer composites,waste materials
更新于2025-09-23 15:22:29
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Spectroscopy approach to methanol detection in waste fat methyl esters
摘要： Second-generation biodiesel manufactured from waste cooking oils (WCO) and inedible animal fats (AF) are one of the alternatives to the first generation (1G) vegetable oil-based biodiesel. In this study, a quality control method is proposed to evaluate methanol content in waste fat methyl esters and is based on near infrared spectroscopy (NIR) combined with multivariate analysis. More specifically, calibration models are constructed using partial least squares regression (PLS) for the prediction of methanol content in rapeseed oil methyl ester (ROME), waste cooking oil methyl ester (WCOME), chicken fat methyl ester (CFME) and pork fat methyl ester (PFME) by Vis-NIR spectrometer. The calibration models are based on the absorbance spectra and computed data from five wavelength regions of 400–2170 nm, 780–2170 nm, 1400–2170 nm, 1400–1600 nm and 1970–2170 nm. For the cases with the highest prediction ability obtained in this study, the coefficient of determination of the model's goodness-of-fit for methanol concentrations range 0–5% (v/v) was R2 N 0.990, and for concentrations 0–1% (v/v) was R2 N 0.994, indicating the spectroscopic approach effectiveness in methanol content detection relevant to the biofuel quality assessment. A pseudo-univariate limits of detection (LODpu) and quantification (LOQpu) as well as ratio of performance to deviation (RPD) were used to confirm the validity and to evaluate the practical applicability of developed models. In addition, the obtained results indicate the possibility of developing a transmission sensor for online monitoring of the production process and the quality of biofuel.
关键词： PLS calibration models,Waste cooking oil,Animal fat biofuel,Vis-NIR spectroscopy
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Use of ilmenite and boron waste as a radiation shielding panel
摘要： Ilmenite is an important and interesting metallic oxide mineral. It is a titanium-iron oxide mineral with formula FeTiO3. It is the primary ore of iron and titanium metal. The largest boron mineral reserves in the world are located in Turkey. Each year 900,000 tons of boron waste results from boron production. Boron waste is caused big environmental problem in Turkey. In this study, evaluation of ilmenite and boron waste was performed to investigate the potential use in shielding materials. In this study, incorporation of ilmenite-boron waste has been investigated for its effect on the physical, morphological, mechanical and shielding properties. Several mixtures were prepared with different proportions of ilmenite and boron waste ranging from 0% to 50%. Then they dried and sintered at 1000, 1050 and 1100 (cid:113)C for 2 hours. Sintered samples were characterized.
关键词： environmental problem,ilmenite,boron waste,sintering,radiation shielding
更新于2025-09-23 15:21:21
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Visible Light TiO <sub/>2</sub> Photocatalyst Composite Based on Carbon Microfiber Derived from Human Hair
摘要： The present work reports titanium dioxide (TiO2) photocatalyst composite based on human hair that can operate efficiently under visible light. The human hair melanin structure contains active sites, which can be described as a carbon compound derived from a Quinone where one of two oxygen atoms is bonded to a hydrogen radical and that can be reversibly photogenerated under visible or ultraviolet irradiation. The human hair-derived microfibers (HHDMs) were created by the pyrolyzing hair at 850 °C, resulting in a rod-like hollow structure. TiO2 was immobilized on the pyrolyzed hair by a simple self-template method. The resulting composite was calcined at five different temperatures (150 to 350 °C). The HHDM and HHDM-TiO2 morphologies and the chemical compositions were characterized using scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). The HHDM-TiO2 photocatalytic efficiency in degrading methylene blue was investigated and compared to that of a conventional TiO2 catalyst (P25). HHDM-TiO2 was more effective for methylene blue degradation under visible light than the conventional P25 catalyst suspension due to the unique photosensitivity and porous structure of the composite. The catalyst calcined at 300 °C showed the best performance, which was 71% higher than that of the P25 catalyst.
关键词： Semiconductors,Immobilization,Titanium Dioxide,Waste prevention,Photocatalysis
更新于2025-09-23 15:21:21