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Highly efficient removal of phosphonates from water by a combined Fe(III)/UV/co-precipitation process
摘要： Considerable amount of phosphorous is present as organic phosphonates (usually in the form of metal complexes, e.g., Ca(II)-phosphonate) in domestic and industrial effluents, which cannot be effectively removed by traditional processes for phosphate. Herein, we employed a proprietary process, i.e., Fe(III) displacement/UV irradiation/co-precipitation (denoted Fe(III)/UV/NaOH), to enable an efficient removal of Ca(II)-phosphonate complexes from water. The combined process includes three basic steps, i.e., Fe(III) replacement with the complexed Ca(II) to form Fe(III)-phosphonate of high photo-reactivity, UV-mediated degradation of Fe(III)-phosphonate to form phosphate and other intermediates, and the final phosphorous removal via co-precipitation at pH=6. The operational conditions for the combined process to remove a typical phosphonate Ca(II)-NTMP (nitrilotrismethylenephosphonate) are optimized, where ~60% NTMP is transformed to phosphate with the total phosphorous reduction from 1.81 mg/L to 0.17 mg/L. Under UV irradiation, the cleavage of NTMP is identified at the C-N and C-P bonds to form the intermediate products and phosphate in sequence. Also, the combined process is employed for treatment of two authentic effluents before and after activated sludge treatment, resulting in the phosphorous drop from 4.3 mg/L to 0.23 mg/L and from 0.90 mg/L to 0.14 mg/L respectively, which is much superior to other processes including Fenton/co-precipitation. In general, the combined process exhibits great potential for efficient removal of phosphonates from contaminated waters.
关键词： Photolysis,Fe(III) replacement,Advanced treatment,Phosphonates
更新于2025-09-23 15:22:29
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Determination of the microplastics emission in the effluent of a municipal waste water treatment plant using Raman microspectroscopy
摘要： Samples from the secondary clarifier effluent of a waste water treatment plant (serving 98500 inhabitants) were analyzed to determine the microplastics (MP) emission. The samples were collected using a stainless steel centrifugal pump and filtered through a 10 mm stainless steel cartridge filter. Microplastics particles (MPPs) and microplastics fibers (MPFs) were recovered by chemical and physical sample purification. To remove natural organic matter, the samples were first subjected to oxidative treatment with H2O2 and NaClO. Inorganic materials were subsequently removed by density separation in ZnCl2 (r = 1.9 g/cm3) using a centrifuge. Special centrifuge tubes were developed for this purpose. Sample analysis was performed on a Si filter by Raman micro-spectroscopy. Particles with a diameter (dp) ≥ 10 mm were analyzed. The results were differentiated by dry and wet weather samples. On average, 5900 MPPs m?3 were identified in the effluent on wet weather days compared to 3000 MPPs m?3 on dry weather days. Most of the MPPs detected were in the 30 mm < dp < 100 mm size range. The MPFs ranged between 100 mm and 1000 mm in length. While most of the MPFs were of PET origin, the MPPs consisted mainly of PET, PP, PE and PS.
关键词： Raman microspectroscopy,Oxidative treatment,Si filter,Centrifugation,Microplastics emission,WWTP effluent
更新于2025-09-23 15:22:29
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Sono-solvothermal fabrication of ball-flowerlike Bi2O7Sn2-Bi7O9I3 nanophotocatalyst with efficient solar-light-driven activity for degradation of antibiotic tetracycline
摘要： A novel Bi2O7Sn2-Bi7O9I3 nano-heterostructure photocatalyst with the different weighted percentages and as I-type heterojunction, which acts as pseudo-type II heterojunction, were successfully synthesized using sono-solvothermal manner for the first time. The coupled nanophotocatalysts with various weighted contents of Bi2O7Sn2 and Bi7O9I3 were characterized with XRD, FESEM, EDX, DRS, BET-BJH and pHpzc analyses. Meanwhile, the photocatalytic activity of various nanocomposites was evaluated in the remediation of the antibiotic tetracycline after 90 min irradiation. Results depicted that the ball-flowerlike Bi2O7Sn2(60)-Bi7O9I3(40) nanophotocatalyst, as a mesoporous structure and the type I-heterostructure which appears as an efficient solar-light-driven pseudo-type II heterojunction, represented the best photocatalytic efficiency. This is addressed by the suitable absorption of light range, high separation of charge carriers and its large surface area which provide more active sites for absorption of tetracycline molecules. Furthermore, to elucidate the how the influence of various parameters on the photodegradation efficiency, the different experiments were conducted over Bi2O7Sn2(60)-Bi7O9I3(40). The high activity was obtained in the medium with pH = 6, catalyst loading = 1 g/L and tetracycline concentration = 35 mg/L. Moreover, the capable of reusability and reaction mechanism of improved photodegradation on mentioned photocatalyst were investigated.
关键词： Sono-solvothermal,Water treatment,Antibiotic tetracycline,Photodegradation,Bi2O7Sn2-Bi7O9I3 nanophotocatalyst
更新于2025-09-23 15:22:29
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Contact Angle Relaxation and Long-lasting Hydrophilicity of Sputtered Anatase TiO <sub/>2</sub> Thin Films by Novel Quantitative XPS Analysis
摘要： The contact angle relaxation of TiO2 surfaces is an important problem that must be understood, particularly for long-lasting hydrophilicity under dark conditions. The relaxation of sputtered anatase TiO2 thin films over a long time (~22 days) in an atmospheric environment was observed using quantitative XPS analysis. A new peak was identified as H2O within a donor-acceptor complex at ~2.57 eV above the lattice oxygen peak. This donor?acceptor complex turns out to be a key factor for long lasting hydrophilicity, and our model is presented. Adventitious carbon contamination was not the main cause of the contact angle relaxation. Instead, samples with lower amounts of donor?acceptor complexes (IDAC/Ibulk ≤ ~5%) underwent contact angle relaxation over time, and samples with a high density of donor?acceptor complexes (IDAC/Ibulk ≥ ~10%) showed good hydrophilicity (contact angle ≤ 20°) over 22 days. Larger amounts of basic Ti?OH relative to acidic OHbridge (ITi?OH/Ibridge ≥ 1) resulted in greater amounts of donor?acceptor complexes (IDAC/Ibulk ≥ ~10%). Thus, basic Ti?OH groups interact with H2O by forming a strong electrostatic donor?acceptor complex, leading to long-lasting hydrophilicity. Indeed, TiO2 was transformed to show long lasting hydrophilicity by high-density oxygen plasma treatment by forming sufficient Ti?OH groups and H2O molecules in the donor?acceptor complexes. Contact angle relaxation is closely related to the interactions between water molecules and the TiO2 surface in the dark. It is suggested that the relaxation depends on the number of electrostatic donor?acceptor complexes. This study provides new insight by linking theoretical studies with the experimental contact angle at the TiO2 surface in an ambient environment and is the first study that provides the presented relaxation mechanism.
关键词： Hydrophilicity,Sputtering,Plasma treatment,Contact angle relaxation,XPS analysis,Donor-acceptor complex,TiO2 thin films
更新于2025-09-23 15:22:29
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Copper Nanowire Dispersion through an Electrostatic Dispersion Mechanism for High-Performance Flexible Transparent Conducting Films and Optoelectronic Devices
摘要： Highly dispersed copper nanowire (CuNW) is an essential prerequisite for its practical application in various electronic devices. At present, the dispersion of CuNW is almost realized through the steric hindrance effect of polymers. However, the high post-treatment temperature of polymers makes this dispersion mechanism impractical for many actual applications. Here, after investigating the relationships between the electrostatic dispersion force and influence factors, an electrostatic dispersion mechanism is refined by us. Under the guidance of this mechanism, high dispersion of CuNW and a record low post-treatment temperature (80 ℃ ) are realized simultaneously. The high dispersity endows CuNW with good stability (–45.66 mV) in water-based ink, high uniformity (65.7 ± 2.5 Ω sq-1) in the prepared transparent conducting film (TCF) (23 cm × 23 cm) and industrial film-preparation process which are the issues that hinder the widespread application of CuNW-based TCF at present. The low post-treatment temperature makes CuNW possible for applying on any substrate. In addition, the charge modifier, 2-mercaptoethanol, enables CuNW to resist oxidation well. Finally, flexible optoelectronic devices employing the CuNW film as the electrode are fabricated and show efficiencies comparable to those of optoelectronic devices on ITO/glass.
关键词： copper nanowires,flexible optoelectronic devices,electrostatic dispersion mechanism,transparent conducting films,post-treatment temperatures
更新于2025-09-23 15:22:29
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AIP Conference Proceedings [Author(s) GREEN DESIGN AND MANUFACTURE: ADVANCED AND EMERGING APPLICATIONS: Proceedings of the 4th International Conference on Green Design and Manufacture 2018 - Ho Chi Minh, Vietnam (29–30 April 2018)] - Computational fluid dynamic analysis for solar powered water treatment device
摘要： Solar Powered Water Treatment Device (SWAD) is an effective and affordable water treatment device using low-cost treatment materials to treat stagnant water bodies such as lakes and ponds. SWAD is an environmental friendly device as it does not attached to any power source. The objective of this project is to design and develop 3D SWAD using 3D CAD software. Other than that, the objective is to simulate and model the water flow, spatial distribution of velocity and pressure of SWAD by Computational Fluid Dynamic (CFD). CFD analysis was used to capture the efficiency of the SWAD by simulate and model the water flows, pressure and velocity. Based on the results, the maximum velocity magnitude was 2.57m/s at outlet of pipe. The velocity contour demonstrated has high speed at the pipe outlet. The pressure magnitude was in between 9246 Pa to 2609 Pa. The results of water quality parameters has proved that the water development and the direction of water flow of the SWAD can remove the pollutant efficiently. The results of vector plot, velocity contour, water flow streamline and pressure contour were effectively determined.
关键词： Computational Fluid Dynamic,Solar Powered Water Treatment Device
更新于2025-09-23 15:22:29
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[IEEE 2018 International Flexible Electronics Technology Conference (IFETC) - Ottawa, ON, Canada (2018.8.7-2018.8.9)] 2018 International Flexible Electronics Technology Conference (IFETC) - Optimizing the Electrical Conductivity of Screen Printed Silver Conductive Tracks by Post Treatment
摘要： Screen printed silver conductive tracks have been used or are being explored for applications in membrane switches, solar cells, radio frequency identification (RFID) antennas, diabetic testing strips, sensors etc. For many of these applications, optimizing the electric conductivity of the printed tracks is crucial. It has been noticed that the electric conductivity of the printed conductive tracks are highly dependent on the post-processing conditions. However, the understanding of the effect is limited. In this paper, preliminary study results show that ambient temperature drying followed by heat treatment offers the lowest resistance (highest conductance) for printed conductive tracks.
关键词： Electrical Conductivity,Printed Conductive Tracks,Post Thermal Treatment,Curing
更新于2025-09-23 15:22:29
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Simultaneous photocatalytic reduction/degradation of divalent nickel/naphthalene pollutants in aqueous solutions
摘要： Toxic heavy metals and organic pollutants are simultaneously exist in the wastewater of some industries. This study explores reduction of toxic divalent nickel ions, from either nitrate or sulfate salts, coupled with naphthalene (NA) degradation using titania photocatalyst in an efficient photo-sono reactor. A synergism appears when reduction and degradation treatments perform simultaneously in the media. With initial concentrations of [Ni(II)]0 = 5 mg/L and [NA]0 = 10 mg/L, under dominant mild conditions, removal efficiencies of 54.5% and 56.6% were corresponding to Ni(II) and NA when nickel nitrate was used, respectively. These efficiencies were enhanced to 59.2% and 57.5% with nickel sulfate, all after 90 min operations. For evaluating the mechanism of reactions, reactive oxygen species analysis on solutions as well as FTIR, SEM and BET analysis on the titania nanoparticles, before and after usage, were performed. The reaction kinetic was also followed for individual species in the mixed solution and accordingly, the energy consumption was evaluated for one order of magnitude decrease in pollutants concentration. The high performance of the used method was revealed in comparison to the similar reported reduction/degradation processes.
关键词： divalent nickel,kinetic,energy consumption,naphthalene,photocatalytic treatment
更新于2025-09-23 15:22:29
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Growth Condition-Oriented Defect Engineering for Changes in Au–ZnO Contact Behavior from Schottky to Ohmic and Vice Versa
摘要： ZnO has the built-in characteristics of both ionic and covalent compound semiconductors, which makes the metal–ZnO carrier transport mechanism quite intricate. The growth mechanism-centric change in ZnO defect density and carrier concentration also makes the contact formation and behavior unpredictable. This study investigates the uncertainty in Au–ZnO contact behavior for application-oriented research and the development on ZnO nanostructures. Herein, we explain the phenomenon for how Au–ZnO contact could be rectifying or non-rectifying. Growth method-dependent defect engineering was exploited to explain the change in Schottky barrier heights at the Au–ZnO interface, and the change in device characteristics from Schottky to Ohmic and vice versa. The ZnO nanorods were fabricated via aqueous chemical growth (ACG) and microwave-assisted growth (MAG) methods. For further investigations, one ACG sample was doped with Ga, and another was subjected to oxygen plasma treatment (OPT). The ACG and Ga-doped ACG samples showed a quasi-Ohmic and Ohmic behavior, respectively, because of a high surface and subsurface level donor defect-centric Schottky barrier pinning at the Au–ZnO interface. However, the ACG-OPT and MAG samples showed a more pronounced Schottky contact because of the presence of low defect-centric carrier concentration via MAG, and the removal of the surface accumulation layer via the OPT process.
关键词： oxygen plasma treatment,nanorod,ZnO,crystal defects,microwave,metal-semiconductor contact
更新于2025-09-23 15:22:29
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ZnO Tetrapods for Potential Photocatalytic Dye Degradation
摘要： In this study, a facile method was used to prepare ZnO tetrapods for potential dye degradation applications. Field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX) and UV-Vis spectroscopy were employed to investigate the morphology, chemical composition, and photocatalytic properties of prepared ZnO tetrapods. A Rhodamine B (RB) dye was used as a model dye to study the photocatalytic activity of the prepared sample. It was shown that RB dye can be efficiently degraded in the presence of ZnO tetrapods under continuous UV-light illumination. Thus, prepared ZnO tetrapods with excellent photocatalytic properties can be potentially used in wastewater treatment.
关键词： tetrapods,ZnO,photocatalytic activity,wastewater treatment
更新于2025-09-23 15:22:29