Search

As a kind of emerging contaminant, microplastics (MPs) widely exist in environments around the world and may carry other chemical pollutants. Besides, radioactive pollutants in water are getting more and more attention due to the discharge of wastewater from the Fukushima nuclear power plant. Among them, Uranium is an important fuel substance in nuclear power plants, which has toxicity of radioactivity and heavy metals. In order to research the interaction between MPs and uranium in water, batch experiments were conducted to study the adsorption behavior of radioactive heavy metal uranium (U(VI)) by ordinary PET MPs. The results showed that the adsorption amount of U(VI) onto PET increased (69.02%) after aging. The kinetic adsorption behavior of U(VI) could be explained by pseudo-second-order and Elovich models, and the isothermal adsorption behavior of U(VI) was well fitted by Langmuir and Sips models. The adsorption amounts were in the order of aged PET > virgin PET and ultrapure water > simulated freshwater. Besides, external diffusion and internal diffusion were included in the adsorption process. The adsorption capacity was affected by pH and salinity. The adsorption mechanisms included pore filling, electrostatic interaction, and surface complexation. The properties of MPs and the environment are the main factors affecting the adsorption process. The study elucidates the adsorption mechanism of U(VI) onto MPs in ultrapure water and simulated freshwater, aiming to assess the potential risk to aquatic environments where natural MPs and uranium ions coexist. [ABSTRACT FROM AUTHOR]

Copyright of Knowledge: International Journal is the property of Institute for Knowledge Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Because of investigating effect of mixed ultra-fine ozone-rich bubble (UFORB) liquids on the degradation of organic compounds, we observed molar concentration of aqueous solutions of methylene blue (organic compound model) against elapsed time by using UFORB or ozone-water (OW) suspended in ultrapure water (UPW) or tap-water (TAP). Excellently lower concentration of methylene blue by using UFORB exhibited. Compared with that of OW, effect of both high decomposing ability and short processing time was excellently obtained. For discussing the experimental results, additional two experiments were conducted. Dissolved ozone-concentration of UFORB suspended in UPW or TAP was measured. For case of UFORB, highly ozoneconcentration in ultrapure water exhibited and was independence of elapsed time. However, that in tap-water decreased against elapsed time within the experimental errors. Relationship between number density and particle diameter of ultra-fine bubble was measured. Peak diameter of UFORBTAP was smaller than that of UFORB-UPW in relatively initial times. Moreover, differences between stability of ultra-fine bubble and ozone-concentration suspended in UPW or TAP was discussed. [ABSTRACT FROM AUTHOR]

This study explores a new governance mechanism aimed at regional integration and explains how this mechanism can achieve optimal governance of water resources through the division of labour in politics and the economy. This study adopts political economic geography as the research approach. The data used in the analysis were obtained from official documents, interviews and field investigations, and its authenticity was interactively checked via triangulation. The results show that ‘spatial shifts’ were the driving force behind water redistribution. The division of labour between politics and the economy eliminates obstacles to water distribution through the mutual adjustment and division of underground rhizomes; ‘creative destruction’ and ‘destructive creation’ are alternately used to achieve dialectical progress. This study concludes that in this case, the process of regional integration simultaneously generates circular mechanisms in which political power and economic productivity are consolidated.

Among the various substances found in the feed source for the production of ultrapure water (UPW), urea is challenging to remove because it is a small molecular weight molecule that is not easily oxidized and does not carry a charge under neutral pH conditions. Urease enzyme, found in various organisms such as plants and bacteria, catalyze the hydrolysis of urea into carbon dioxide and ammonia. In this study, urease was immobilized on the polyamide layer of a reverse osmosis (RO) membrane to remove urea in UPW systems. The removal efficiency of urea by urease-coated RO membrane showed up to 27.9 % higher urea removal efficiency compared to the pristine membrane. This increase in urea removal can be attributed to both physical and biological effects from the urease coating on the membrane. Firstly, urease on the membrane surface can act as an additional physical barrier for urea to pass through. Secondly, urea can be hydrolyzed by the enzyme when it passes through the urease-coated RO membrane. In a two-pass RO system typical for UPW production, the removal of urea by a urease-coated membrane would be enhanced by twofold. This overall method can significantly increase the removal efficiency of urea in UPW systems, especially when considering the compounded removal by the urease coating, rejection by RO, and additional reactions by other treatment processes. Moreover, urea in UPW systems can be removed without the installment of additional processes by simply coating urease on the existing RO membranes.

Ultrapure water production is vital for sustainable green hydrogen production by electrolysis. The current industrial process to generate ultrapure water involves energy-intensive processes, such as reverse osmosis. This study demonstrates a facile method to produce ultrapure water from simulated seawater using a low capital cost and low-energy-consuming membrane distillation (MD) approach that is driven by the waste heat from photovoltaic (PV) panels. To optimize the PV-MD operation, modeling efforts to design a multilayered MD system were carried out. The results were used to guide the construction of several prototype devices using different materials. The best performing PV-MD device, containing evaporation and condensation regions made from steel sheets and polytetrafluoroethylene (PTFE) membranes, can produce high-purity water with conductivity less than 40 mS and flux higher than 100 g/m2 h, which is suitable for typical electrolyzer use. [ABSTRACT FROM AUTHOR]

With the expansion of the semiconductor industry, determining the huge associated water and energy consumption and accomplishing sustainable development can be key issues for this industry. This study surveyed the sustainability reports of 28 semiconductor corporations and summarized their environmental stewardship information. Overall, the total water withdrawal in 2021 was 7.89 ​× ​108 ​m3, total energy consumption was 1.49 ​× ​1011 ​kWh, and total greenhouse gas (GHG) emissions were 7.15 ​× ​107 tons CO2 equivalent. The total Scope 1 and Scope 2 GHG emissions were 2.74 and 4.41 ​× ​107 ​t CO2 equivalent, respectively. Surface water intake, municipal water supply, groundwater withdrawal, third party supply, and external reclaimed water intake accounted for 47.0%, 35.3%, 8.5%, 5.8%, and 3.2% of total water use, respectively. Electricity, fossil fuel, renewable energy, and others accounted for 83.7%, 12.0%, 2.7%, and 1.7% of the total energy use. In 2021, average water use, energy consumption, and GHG emissions were calculated to be 8.22 ​L/cm2, 1.15 ​kWh/cm2, and 0.84 ​kg CO2 equivalent/cm2, respectively, based on announced data. Ultrapure water consumption was predicted to be 5.51 and 0.95 ​× ​108 ​m3 worldwide and for China, respectively. Effective sustainability strategies are supposed to be implemented to meet the considerable growth in water and energy consumption and GHG emissions for the semiconductor industry worldwide and in China.

Monitoring the content of dissolved ozone in purified water is often mandatory to ensure the appropriate levels of disinfection and sanitization. However, quantification bears challenges as colorimetric assays require laborious off‐line analysis, while commercially available instruments for electrochemical process analysis are expensive and often lack the possibility for miniaturization and discretionary installation. In this study, potentiometric ionic polymer metal composite (IPMC) sensors for the determination of dissolved ozone in ultrapure water (UPW) systems are presented. Commercially available polymer electrolyte membranes are treated via an impregnation‐reduction method to obtain nanostructured platinum layers. By applying 25 different synthesis conditions, layer thicknesses of 2.2 to 12.6 µm are obtained. Supporting radiographic analyses indicate that the platinum concentration of the impregnation solution has the highest influence on the obtained metal loading. The sensor response behavior is explained by a Langmuir pseudo‐isotherm model and allows the quantification of dissolved ozone to trace levels of less than 10 µg L−1. Additional statistical evaluations show that the expected Pt loading and radiographic blackening levels can be predicted with high accuracy and significance (R2adj. > 0.90, p < 10−10) solely from given synthesis conditions. [ABSTRACT FROM AUTHOR]

Conventional spectrophotometric methods were unable to accurately detect urea concentrations below 100 μg/L. A modified spectrophotometric method was developed to determine the trace urea in the ultrapure water (UPW) production process of the semiconductor manufacturing industry. This method was optimized based on the dosage of chemical agents, length of the optical path, and mode of the water bath. Metal ions were added to promote the stability of the chromogenic system. A calibration graph was observed with ideal linearity in the range of 0.8–100 μg/L. The detection and quantification limits of urea were 0.24 and 0.80 μg/L, respectively. The distribution of urea in raw water for the UPW production process was observed and the urea in tap water was 10–20 μg/L. The urea of municipal reclaimed water was 24–40 μg/L, which was twice that of industrial reclaimed water at 10–18 μg/L. The total removal rate of urea by the UPW production process was 50–70%. Reverse osmosis membranes played a critical role in the removal of urea (over 30%). The urea in the final UPW produced from tap water was approximately 4.1 μg/L, which creates a potential risk of excessive total organic carbon. HIGHLIGHTS A spectrophotometric method for the determination of trace urea during ultrapure production process was first established.; Stability of the absorbance in the color reaction was increased by doping metal ions.; The urea concentration of municipal reclaimed water was twice that of industrial reclaimed water.; The urea removal efficiencies in each unit of the ultrapure water production process were explored.;

Thermal power plants will function as a flexible load regulation in a low-carbon grid, which requires operation adaption for the whole system. Energy transition in the electricity sector is the core to realizing carbon neutrality. The power grid will be gradually dominated by renewable energy, such as wind power and photovoltaic solar power. However, renewable energy has problems such as insufficient power supply and output fluctuation; thermal power will be required to regulate the peak load flexibly to meet demand. Therefore, the supply of boiler make-up water prepared by electrodeionization (EDI) in thermal power plants should also be flexibly changed. This study focused on the ultrapure water preparation system by EDI with variable flow rates. For an EDI system with a maximum ultrapure water capacity of 20 m3/h, the power consumption, annual cost, and carbon footprint of different designs are compared. The operation parameters were optimized based on the optimal cost design when the temporal demand of boiler make-up water is reduced to 75%, 50%, and 25%, respectively, considering thermal power as peak load regulation technology. The results showed that the optimized system could significantly reduce power consumption and carbon footprint by up to 30.21% and 30.30%, respectively. The proposed strategy is expected to be widely applied for design and operation optimization when considering the low-carbon but unstable energy system dominated by renewable energy. The carbon footprint could be a feasible optimization object to balance the greenhouse gas emissions from the module manufacturing and operation consumption. [ABSTRACT FROM AUTHOR]

Urea abatement has been a prominent challenge for UPW production. This research proposed a productive strategy combining pre-chlorination and VUV/UV processes under acidic conditions to settle this problem. This study first revealed the reaction kinetics between urea and free chlorine in a large pH range from 2.5 to 9.6, where the reaction constant rate varied from 0.06 to 0.46 M−1·s−1. Substitution reaction mediated by Cl 2 was the dominant process at low pH (pH<3). The differences of dominant pathways resulted in the differences in reaction products: The detected concentration of dichloramine at pH 2.5 was twice that at pH 4.5 and 6.5. Further, this study found that pre-chlorination/VUV/UV process could achieve the thorough removal of 2-mg/L urea with chlorination of less than 5 min and VUV/UV irradiation of less than 200 mJ/cm2. Chloride ions, low pH, and higher chlorine dosage were found to be the positive factors to improve urea removal efficiency in pre-chlorination/VUV/UV process. The reaction rate constants between chlorourea with·OH and·Cl were calculated to be 3.62 × 107 and 2.26 × 109 L·mol−1·s−1, respectively.·Cl,·OH and photolysis contributed 60.5 %, 22.9 % and 16.6 % in chlorourea degradation, respectively. Pre-chlorination/VUV/UV achieved a DOC removal efficiency of 78.5 %. And nitrogen in urea was converted into inorganic nitrogenous compounds. Finally, compared with direct VUV/UV/chlorine and VUV/UV/persulfate processes, this process saved more than 70 % of energy in VUV/UV unit. [Display omitted] • Proposed one of most efficient ways to remove urea in UPW production. • Revealed the reaction kinetics of urea chlorination in a large pH range. • Investigated promotive factors of pre-chlorination/VUV/UV for urea removal. • Illustrated the key enhancement mechanisms in urea removal. • Gained a high DOC removal rate with no organic nitrogenous byproducts. [ABSTRACT FROM AUTHOR]

The ITER Neutral Beam Test Facility (NBTF) is hosted in Padua and includes two experiments: MITICA, the 1 MeV full-scale prototype of the ITER HNB injector, and SPIDER, the 100 keV full-size ITER Radio Frequency (RF) negative ion source. SPIDER and MITICA experiments are actively cooled by Ultrapure Water (UPW) to electrically insulate in-vessel components that are biased to high voltage levels. Water conductivity is an important monitored parameter to ensure components' insulation by limiting the leakage current of active cooled equipment. A very low conductivity water is especially important in MITICA, where components need to operate up to 1 MVdc, an insulation level beyond the actual industrial standard. Careful selection of suitable materials for any in-vessel (vacuum insulation) and out-vessel component (air insulation) is of utmost importance, as their interaction with water and different environment may affect their chemical and mechanical properties. Additionally, materials selection can severely influence water chemical characteristics: cooling circuits are made of metals (copper, aluminium, steel) and insulating materials (plastic, rubber) when connecting parts at different electric potentials. During the first years of cooling plant exploitation, it was shown that water degrades more quickly than estimated by design. The Primary Circuits (PCs) that showed the most severe water degradation during operation are SPIDER and MITICA power supply ones, respectively called PC01 and PC08. This paper describes the results of specific experimental tests performed on MITICA PC08 to evaluate possible causes of water degradation and detect sources of contaminants that might compromise future experimental campaigns. The cooling circuit was subdivided in different sections and water circulation tests were performed at constant temperature and flowrate. Water samples were collected and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analyses were performed to quantify the type and amount of metals released. Moreover, components samples collected along their cooling circuits were characterized by Scanning Electron Microscope (SEM) technique to detect undesired contaminants and immersed in UPW to study their corrosion behaviour using metal release tests. [ABSTRACT FROM AUTHOR]

Ultrapure water production is vital for sustainable green hydrogen production by electrolysis. The current industrial process to generate ultrapure water involves energy-intensive processes, such as reverse osmosis. This study demonstrates a facile method to produce ultrapure water from simulated seawater using a low capital cost and low-energy-consuming membrane distillation (MD) approach that is driven by the waste heat from photovoltaic (PV) panels. To optimize the PV-MD operation, modeling efforts to design a multilayered MD system were carried out. The results were used to guide the construction of several prototype devices using different materials. The best performing PV-MD device, containing evaporation and condensation regions made from steel sheets and polytetrafluoroethylene (PTFE) membranes, can produce high-purity water with conductivity less than 40 mS and flux higher than 100 g/m2 h, which is suitable for typical electrolyzer use.

Water is a key element of all socioeconomic processes. Ultrapure water, with hardness less than 1 ppm, is currently widely employed in a variety of industries, including the semiconductor industry, the pharmaceutical industry, and electric power generation. To produce water with high-purity from well water, different purification methods such as thermal and membrane processes are performed. EDI is mainly used for ultrapure water production. Usually, this process is integrated with reverse osmosis (RO) to produce EDI feed water with a hardness of less than 1 ppm. In this study, ultrapure water was produced from a water well using a novel integrated UF- Ion Exchanger Textile (UF-IET)- electrodeionization (EDI) system. The UF IETTEXTILE permeate with a conductivity of 248 µS/cm was fed into the EDI cell to generate the ultrapure water. It has been revealed that the product conductivity decreased as the EDI current density increased and the feed velocity increased. The results obtained revealed that the suggested hybrid separation process UFIET/EDI system is an innovative solution for ultrapure water production with lower energy consumption and investment than the conventional RO/EDI system. [ABSTRACT FROM AUTHOR]

The content of total organic carbon is an important indicator for ultrapure water. The existing TOC measuring device based on UV oxidation uses a large volume oxidation cell, which leads to low oxidation efficiency. Also, using NDIR sensors to measure the carbon dioxide content will generate a series of complex processes and eventually causes low measurement efficiency and accuracy. To address these problems, we designed a new type of TOC measuring device combining UV oxidation and electrical conductivity measurement. A small volume oxidation cell with precise structure is designed and applied to this device. The optimum volume was obtained through a series of comparative experiments, both oxidation rate and accuracy are improved. The hardware and software development of electronic control system are carried out based on a high performance and low power embedded micro-controller. Through a series of experiments, it is proved that this design not only improves the measurement efficiency, but also has the advantages of high accuracy, low cost, no pollution and low power consumption. [ABSTRACT FROM AUTHOR]

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose low background Liquid Scintillator (LS) detector, was proposed primarily to determine the neutrino mass ordering. To suppress the radioactivity from the surrounding rocks and tag cosmic muons, the JUNO central detector is submerged in a Water Cherenkov Detector (WCD). In addition to being used in the WCD, ultrapure water is used in LS filling, for which the 226Ra concentration in water needs to be less than 50 μ Bq/m 3. To precisely measure the 226Ra concentration in water, a 6.0 μ Bq/m 3 226Ra concentration in water measurement system has been developed. In this paper, the detail of the measurement system as well as the 226Ra concentration measurement result in regular EWII ultrapure water will be presented. [ABSTRACT FROM AUTHOR]

In this study, three desalination exergy analysis models including the Cerci et al. model (Model A), Drioli et al. model (Model B) and electrolyte solution model (Model C), were developed on an existing reverse osmosis (RO) desalination plant in Oman (Plant ALG). A modified ultrapure water (UPW) unit fed by Plant ALG has also been proposed (Plant A) based on the technology used in a UPW unit operated under the climate of Europe and fed by European river water (Plant B). The most suitable exergy model for characterizing the proposed UPW production plant was used. Model C was found to be the most proper model among its counterparts. It reflected the electrolytic behavior of the relevant streams and considered as the appropriate model. The major exergy destruction sites were also identified, and the exergy efficiency was calculated. The electro-de-ionization (EDI) and the RO unit were the highest exergy destructive components in Plant A. [ABSTRACT FROM AUTHOR]

Ultrasound was irradiated to ultrapure water. Ultrafine bubbles with a diameter of 90 - 100 nm were generated. Number concentration of ultrafine bubbles increased with time and approached asymptotically to an equilibrium value. Ultrafine bubble concentration increased with increasing ultrasonic power and decreasing frequency. For comparison, highly concentrated ultrafine bubble water was prepared by pressurized dissolution method, and ultrasound was also irradiated to the ultrafine bubble water. Reduction of ultrafine bubbles was observed and ultrafine bubble concentration decreased to the equilibrium value. Ultrafine bubble concentration decreased with increasing ultrasonic power and frequency. Generation and reduction of ultrafine bubbles by ultrasound was modeled to analyze experimental data. The results calculated by our model were in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Objectives:This study aims to summarize the market status, patent applications, and technology trends for the production of ultrapure water in semiconductor industries. In addition, the potential of technological localization of ultrapure water production facility is reviewed in order to incubate domestic core technologies as well as to reduce the technical dependence to the market stake holders. Methods:Through the collection and summary of information from global water institute (GWI), market analyst firms in ultrapure water fields, and the patent analysis for the past 10 years, the technological gap between domestic and market leading in Japan, the United States, and Europe were analyzed. In addition, the research trend related to the core removal processes for the production of ultrapure water was also analyzed. Results and Discussion:As a result of market analysis in the industrial water sector, the capital investment is expected to reach USD 39.9 billion by 2024, with a steady growth of 4.1% per year. The unit processes required for the production of ultrapure water becomes more complex and diversified, and the recent technological advancement has been mainly put on the development of eco-friendly water treatment processes such as electrodeionization (EDI) in order to reduce the chemical usage. In addition, research on the development of new processes for the treatment of hardly degradable trace substances (i.e. urea, THM, IPA, etc.) is actively under investigation. However, the patent analysis revealed that the three Japanese companies occupied 71% of the world’s patents on the ultrapure water production. Conclusions:In ultrapure water production technology, the design of unit processes is important, and the design of a system that combines and arranges unit processes is the core technology. Thus, the incubation of domestic companies that have ability to design the array of unit processes for ultrapure water production is necessary for the localization of ultrapure water technology. However, although a few companies have completed the commercialization of core technologies, there is lack of the test field to evaluate the long-term performance of products. Therefore, for the development of domestic technologies in the ultrapure water production, it is necessary to construct a test-bed capable of evaluating the performance of domestic products. In addition, it is expected that localization of ultrapure water production technology will be facilitated with the participation of consumers.

The BR2 nuclear research reactor in Mol, Belgium, runs in successive phases of operation (cycles) and shutdown, whereby a water basin surrounding the reactor vessel undergoes periodic changes in physico-chemical parameters such as flow rate, temperature, and radiation. The aim of this study was to explore the microbial community in this unique environment and to investigate its long-term dynamics using a 16S rRNA amplicon sequencing approach. Results from two sampling campaigns spanning several months showed a clear shift in community profiles: cycles were mostly dominated by two Operational Taxonomic Units (OTUs) assigned to unclassified Gammaproteobacterium and Pelomonas , whereas shutdowns were dominated by an OTU assigned to Methylobacterium. Although 1 year apart, both campaigns showed similar results, indicating that the system remained stable over this 2-year period. The community shifts were linked with changes in physico-chemical parameters by Non-metric Multidimensional Scaling (NMDS) and correlation analyses. In addition, radiation was hypothesized to cause a decrease in cell number, whereas temperature had the opposite effect. Chemoautotrophic use of H2 and dead cell recycling are proposed to be used as a strategies for nutrient retrieval in this extremely oligotrophic environment. [ABSTRACT FROM AUTHOR]

The BR2 nuclear research reactor in Mol, Belgium, runs in successive phases of operation (cycles) and shutdown, whereby a water basin surrounding the reactor vessel undergoes periodic changes in physico-chemical parameters such as flow rate, temperature, and radiation. The aim of this study was to explore the microbial community in this unique environment and to investigate its long-term dynamics using a 16S rRNA amplicon sequencing approach. Results from two sampling campaigns spanning several months showed a clear shift in community profiles: cycles were mostly dominated by two Operational Taxonomic Units (OTUs) assigned to unclassified Gammaproteobacterium and Pelomonas, whereas shutdowns were dominated by an OTU assigned to Methylobacterium. Although 1 year apart, both campaigns showed similar results, indicating that the system remained stable over this 2-year period. The community shifts were linked with changes in physico-chemical parameters by Non-metric Multidimensional Scaling (NMDS) and correlation analyses. In addition, radiation was hypothesized to cause a decrease in cell number, whereas temperature had the opposite effect. Chemoautotrophic use of H2 and dead cell recycling are proposed to be used as a strategies for nutrient retrieval in this extremely oligotrophic environment.

With the increasing demand for ultrapure water in the pharmaceutical and semiconductor industry, the need for precise measuring instruments for those applications is also growing. One critical parameter of water quality is the amount of total organic carbon (TOC). This work presents a system that uses the advantage of the increased oxidation power achieved with UV/O3 advanced oxidation process (AOP) for TOC measurement in combination with a significant miniaturization compared to the state of the art. The miniaturization is achieved by using polymer-electrolyte membrane (PEM) electrolysis cells for ozone generation in combination with UV-LEDs for irradiation of the measuring solution, as both components are significantly smaller than standard equipment. Conductivity measurement after oxidation is the measuring principle and measurements were carried out in the TOC range between 10 and 1000 ppb TOC. The suitability of the system for TOC measurement is demonstrated using the oxidation by ozonation combined with UV irradiation of defined concentrations of isopropyl alcohol (IPA).

Among the various substances found in the feed source for the production of ultrapure water (UPW), urea is challenging to remove because it is a small molecular weight molecule that is not easily oxidized and does not carry a charge under neutral pH conditions. Urease enzyme, found in various organisms such as plants and bacteria, catalyze the hydrolysis of urea into carbon dioxide and ammonia. In this study, urease was immobilized on the polyamide layer of a reverse osmosis (RO) membrane to remove urea in UPW systems. The removal efficiency of urea by urease-coated RO membrane showed up to 27.9 % higher urea removal efficiency compared to the pristine membrane. This increase in urea removal can be attributed to both physical and biological effects from the urease coating on the membrane. Firstly, urease on the membrane surface can act as an additional physical barrier for urea to pass through. Secondly, urea can be hydrolyzed by the enzyme when it passes through the urease-coated RO membrane. In a two-pass RO system typical for UPW production, the removal of urea by a urease-coated membrane would be enhanced by twofold. This overall method can significantly increase the removal efficiency of urea in UPW systems, especially when considering the compounded removal by the urease coating, rejection by RO, and additional reactions by other treatment processes. Moreover, urea in UPW systems can be removed without the installment of additional processes by simply coating urease on the existing RO membranes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Regeneration of pure water is an important issue not only for the healthy life but also for the fine control of precise processes in various industries. One important issue in ultra-high purified water is to reduce the amount of total organic carbon (TOC). Herein, we introduce a new approach to reduce the TOC using the surface silanized nanoparticles, in which the magnetic nanoparticles (mNPs) are silanized and then complexed with ion exchange resin (IER) beads. The Fe 3 O 4 mNPs are surface modified by using high concentrated vinyltrimethoxysilane (VTMS) and then adhered on the surface of IER beads. The surface modified mNPs have a thick-shell of polysiloxane layer varying from 5 to 22 nm depending on the amount of VTMS used, which leads the significant increase of specific surface area. The IER beads embedding VTMS-silanized mNPs achieves about 7 μg/L of the TOC level in ultrapure water system, which is two orders less than 228 μg/L of the feeding water and one order less than 96 μg/L from the system using pristine IER beads. This result is mainly attributed to the polysiloxane layer forming broccoli-like surface structure and some part by the vinyl group of VTMS exposed to the amines in the water. Image 1 [ABSTRACT FROM AUTHOR]

In order to determine six alkaloids (mass fraction) of nicotine, nornicotine, myosmine, anatabine, anabasine, and nicotyrine in tobacco and tobacco products quickly, accurately, and simultaneously, a novel method based on direct analysis of real‐time model in situ ionization technique combined tandem mass spectrometry with a modified sample pretreatment was established, in which experimental parameters such as the type and amount of extraction solvent and injection rate were optimized, respectively. The samples of five commercial cigarettes and five kinds of tobacco leaves were analyzed by the established method, and the determined values were compared with those obtained using a gas chromatography with mass spectrometry method: (1) Under optimized conditions (30 mL ultrapure water as extraction solvent and with extraction rate of 0.6 mm/s), analysis could be completed within 10 min. (2) The linear range of the method was 0.002–2000 μg/g withR2=0.9957, the recovery ranged from 86.8 to 105.6%, and the limit of detection and the limit of quantification were 0.004–0.835 μg/g and 0.013–2.787 μg/g, respectively. (3) The relative standard deviation between direct analysis of real‐time method and the gas chromatography with mass spectrometry method was 0.34–8.83%. The established method is rapid, reliable, and suitable for the ultrafast determination of six alkaloids in tobacco and tobacco products. [ABSTRACT FROM AUTHOR]

Ultrapure water (UPW) is essential in the semiconductor industry for rinsing and cleaning products. With the growing demand for UPW, various feed water sources such as tap water, surface water, and wastewater are utilized to produce UPW. However, these feed water sources contain various low molecular weight organic matters (LMWOMs), which can adversely affect the quality of semiconductors when present in treated UPW. Therefore, achieving the complete removal of LMWOMs is crucial in the UPW production process. However, the current reverse osmosis (RO) and vacuum ultraviolet (VUV) processes employed for UPW production have limitations in achieving complete LMWOM removal. Therefore, this study is conducted to investigate the mechanisms of LMWOM removal in RO and the performance of VUV for high-quality UPW production. Six LMWOMs found in the semiconductor industry were tested for lab- and pilot-scale experiments. The result showed that size exclusion is the main mechanism of LMWOM removal in the RO process. However, methanol, ethanol, and urea were not efficiently removed by RO membranes. In addition, a lab-scale VUV experiment was performed under accelerated conditions to examine the oxidation mechanism of LMWOM. The LMWOM with low reactivity to hydroxyl radicals, such as tetramethylammonium hydroxide (TMAH) and urea, were not removed perfectly within 60 min and 180 min, respectively. Furthermore, a pilot-scale VUV experiment was performed to examine the oxidation of LMWOM under real UPW production conditions. Despite observing a correlation in the pseudo-first-order rate constants between the lab-scale and pilot-scale experiments, the removal of TMAH and urea was still not achieved even with a lamp power of 320 W. As urea was not completely removed by either RO or VUV, strategies for UPW production using current water sources are discussed to develop future UPW technologies. [Display omitted] • The fate of six LMWOMs was analyzed in RO and VUV processes for UPW production. • Size exclusion is the most dominant mechanism for the removal of LMWOMs in RO. • High reactivity with hydroxyl radicals is key to the removal of LMWOMs through VUV. • Pilot-scale VUV results correlate with lab-scale VUV experiments in real UPW conditions. • Urea is the most problematic LMWOM in the UPW process for the semiconductor industry. [ABSTRACT FROM AUTHOR]

In this work, we proposed a new combined process to produce high-purity water which can meet the requirement in many advanced high-tech applications. Here, we mainly focus on the rejection of ions and organic matters, which is characterized by conductivity/resistivity and total organic carbon (TOC), respectively. Ground water with TOC concentration of 373 µg/L and conductivity of 755 µS/cm was fed to the combined process. The effects of granular activated carbons (GACs) (Haycard and Calgon), ultravi- olet (UV) sterilizers (single-wavelength and multiwavelength) and ion-exchange (IX) resins (SMT200L, SMT100L and UP6040) on TOC removal efficiency were systematically investigated. We found that a multiwavelength UV185/254. GAC (Calgon) and IX resin (SMT100L) had a higher TOC removal efficiency. We then optimized ultrapure water system and assembled units to the system, which consisted of double- pass reverse osmosis (RO) membranes, IX resin (SMT100L), multiwavelength UV185/254 sterilizer, GAC (Calgon) + IX resin (SMT100L) and a final filter. The optimized ultrapure water system produced water with a high resistivity (18.2 MO-cm) and low TOC concentration (2.37 µg/L). This research provides a new available combined process for ultrapure water production design. [ABSTRACT FROM AUTHOR]

• A GAC, UV, IX resin, and RO integrated process was optimized for ultrapure water. • For feed water with 755 μS/cm, an effluent resistivity of 18.2 MΩ·cm was achieved. • The system achieved 99.4% TOC removal, and effluent TOC was less than 5 μg/L. • Multiwavelength UV 185/254 sterilizer removed 86% of TOC. In this work, we proposed a new combined process to produce high-purity water which can meet the requirement in many advanced high-tech applications. Here, we mainly focus on the rejection of ions and organic matters, which is characterized by conductivity/resistivity and total organic carbon (TOC), respectively. Ground water with TOC concentration of 373 μg/L and conductivity of 755 μS/cm was fed to the combined process. The effects of granular activated carbons (GACs) (Haycard and Calgon), ultraviolet (UV) sterilizers (single-wavelength and multiwavelength) and ion-exchange (IX) resins (SMT200L, SMT100L and UP6040) on TOC removal efficiency were systematically investigated. We found that a multiwavelength UV 185/254 , GAC (Calgon) and IX resin (SMT100L) had a higher TOC removal efficiency. We then optimized ultrapure water system and assembled units to the system, which consisted of double-pass reverse osmosis (RO) membranes, IX resin (SMT100L), multiwavelength UV 185/254 sterilizer, GAC (Calgon) + IX resin (SMT100L) and a final filter. The optimized ultrapure water system produced water with a high resistivity (18.2 MΩ·cm) and low TOC concentration (2.37 μg/L). This research provides a new available combined process for ultrapure water production design. [ABSTRACT FROM AUTHOR]

The effect of dissolved oxygen (DO) on the degradation of methanol by ultraviolet (UV) light at 185 nm (UV-185) was examined in this study. The experiments were conducted using a bench-scale experimental apparatus that was operated under continuous conditions. In the control tests with various DO conditions, it was confirmed that UV irradiation of water without methanol produced approximately 54 μg/L of H 2 O 2 and removed 15%–90% of the DO. The production of H 2 O 2 was affected by the mixing conditions within the UV reactor and the dose of UV. The degradation efficiency of methanol by UV-185 irradiation improved linearly with increasing DO concentration, with more than 90% DO consumption. The maximum total organic carbon (TOC) removal rate was observed at 100 μg/L DO and 433 mW·sec/cm2, the highest DO and dosage conditions in this study. The production of H 2 O 2 was also affected by DO concentration in the feed water, especially at the high UV dosage, in which lower H 2 O 2 production was observed at higher DO. Image 1 • 185 nm UV irradiated to ultra pure water induced the formation of H 2 O 2 along with the consumption of dissolved oxygen (DO). • DO concentration in water enhanced the removal efficiency of methanol by UV irradiation. • Mixing condition of a reactor was an important factor for deciding the performance of UV oxidation. • Formation of H 2 O 2 was affected by initial methanol and DO concentration. [ABSTRACT FROM AUTHOR]

the analysis of scientific publications and normative documents concerning properties, fields of using and methods of producing ultrapure water was made. Features of determination of electrical conductivity (resistivity) of ultrapure water as the method of the primary control of its quality were considered. The most effective and spread methods of producing ultrapure water on an industrial basis were described as well requirements to the process of its distribution, storage and use, whose fulfillment rules out degradation of water quality. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Bulk nanobubbles are generated by ultrasonic irradiation to ultrapure water. • Nanobubble concentration approaches to an equilibrium value with time. • Nanobubble equilibrium concentration increases with decreasing frequency. • By ultrasonication to high concentration nanobubble water, nanobubbles are reduced. • Generation and reduction of nanobubbles in water by ultrasound are modeled. Abstract To develop a compact generator of bulk nanobubbles (ultrafine bubbles), ultrasound was irradiated to ultrapure water. Effects of ultrasonic power and frequency on nanobubble concentration and diameter were investigated. Nanobubbles with a diameter of 90–100 nm were generated. Number concentration of nanobubbles increased with time and approached asymptotically to an equilibrium value which was about 1.5 × 109 mL−1. Nanobubble concentration increased with increasing ultrasonic power and decreasing frequency. For comparison, ultrasound was also irradiated to high concentration nanobubble water prepared by pressurized dissolution method. Reduction of nanobubbles was measured and nanobubble concentration decreased to the equilibrium value. Nanobubble concentration decreased with increasing ultrasonic power and frequency. Generation and reduction of nanobubbles by ultrasound was modeled to analyze experimental data. The generation rate coefficient of nanobubbles increased with decreasing frequency because cavitation collapse became stronger. The reduction rate constant of nanobubbles at 488 kHz and 1 MHz in high concentration nanobubble water became much higher than those in ultrapure water due to aggregation and floatation of nanobubbles. The equilibrium number concentration increased with decreasing frequency. The results calculated by our model were in good agreement with the experimental data. The nanobubble generator using ultrasound is compact, simple in operation and produce nanobubbles in a short time. This method is contamination-free because the liquid pump is unnecessary. [ABSTRACT FROM AUTHOR]

Consumption of ultrapure water (UPW) during semiconductor manufacturing processes is a very important topic. A new water-dispensing arm design uses a small volume of UPW to remove slurry residue and defects inside pad grooves. This innovative water conditioning arm, in contrast to the conventional atomizer and diamond disc, not only reduces UPW consumption by 87% but also reduces scratch defects caused by diamond abrasive particles. The small water volume arm conditioning system injects UPW with diameters at micro levels. Experimental results show that oxide film removal amount under continuous polishing conditions is maintained at 716 A even after 20 runs. The removal amount and profile not only is maintained but improved by over 2% in comparison with the conventional atomizer under no-dressing conditions. Finally, using a water pump to increase the water pressure up to 50 km/cm2 and treating for 5 s resulted in only 0.5-mm dishing for the IC1010 polish pad. [ABSTRACT FROM AUTHOR]

Copyright of Eastern Mediterranean Health Journal is the property of World Health Organization and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recent progress in third generation solar cells has lead to significant improvement in device efficiency at laboratory conditions. Glass as a substrate plays a major role in superstrate configuration where maximum light is directed towards active layer which increases photo‐carrier generation. In this work, we focus on improving the glass transmittance by creating microstructures using simple, low cost and environmental friendly technique of hydrothermal wet etching. The glass etching was performed by ultrapure water as etchant. The influence of etching parameters viz., temperature (90, 120, 150, 180 and 210 °C) and time (1, 5, 10 and 15 hrs) on optical transmittance, microstructure, and surface roughness has been systematically studied. At optimal etching conditions, an increase in transmittance up to 93.5% in the range of 375–820 nm was observed in comparison to un‐etched glass. Preferential leaching of Na+ is found to be more pronounced phenomena at optimal condition leading to improvement in optical transmittance which is explained by glass‐water interaction. Based on the proposed mechanism, hydrothermal etching of glass with water enhances the light trapping in broad wavelength and can be used as cover glass in superstrate solar cells comprised of tunable band gaps. The silicon solar cell covered with optimized etched glass showed a relative increase of ∼2.2% in power conversion efficiency as compared to a solar cell covered with an un‐etched glass. The soda‐lime glass was etched by ultrapure water using hydrothermal method. The glass surface was modified by network deformation due to ion exchange process. The leaching of ions could be Na and Ca that leads to improve the transmittance and surface roughness of glass so called anti‐reflective surface. Such antireflective glass was used as a cover glass for solar applications. [ABSTRACT FROM AUTHOR]

• VUV and anion-exchange resin reduced organic carbon to an ultralow concentration (5 μg/L). • VUV oxidation transformed electroneutral carbonyls to carboxylic acids. • VUV and anion exchange resin is 2.1–2.4 times of VUV for TOC removal. • Acetate was the primary product penetrating anion-exchange resin. • Modeling was developed to optimize the method performance and cost. Electroneutral carbonyls (ENCs) with low molecular weights (e.g., aldehydes and ketones) are recalcitrant to single water treatment process to achieve ultralow concentration. Residual ENCs are present in reverse osmosis permeate and pose risks to human health during potable use or industrial application in manufacturing processes. Herein, a combined vacuum–UV (VUV) oxidation and anion-exchange resin (AER) adsorption method was developed to treat the ENCs and reduce total organic carbon (TOC) to an ultralow concentration (< 5 μg/L) with high efficiency and at low cost. VUV-AER was 2.1–2.4 times more efficient than VUV alone for the removal of TOC. VUV oxidized the ENCs to electronegative carboxylic acids, which were adsorbed by the AER through electrostatic interactions and hydrogen bonding. When the VUV fluence was lower than 643 mJ cm−2, the AER could not achieve ultralow TOC removal of ENCs. The treat capacity of 1500–2900 valid bed volume (BVs) was achieved after increasing the VUV fluence to 1929 mJ cm−2. The AER could more efficiently adsorb carboxylic acids that contained more carboxylic groups or shorter carbon chain. Acetate was identified as the primary breakthrough product at relatively low VUV fluence, and oxalate was the main byproduct at relatively high VUV fluence. A mathematical model to predict TOC breakthrough was developed considering the VUV–oxidation kinetics and the AER breakthrough curve. The model was used to optimize the method to maximize TOC removal and minimize energy consumption. These results imply that VUV-AER is technically feasible and economically applicable to eliminate recalcitrant ENCs to ultralow concentration for the production of water requires high quality (e.g., potable water or electronic-grade ultrapure water). [Display omitted] [ABSTRACT FROM AUTHOR]