Removal System Research Articles

Stabilizing atomic Co on 2D ordered mesoporous carbon sandwiched MXene for peroxymonosulfate activation: Enhanced performance and electron-transfer mechanism

In this study, a dual-carrier catalyst is designed for efficient Fenton-like catalysis following non-radical electron-transfer process (ETP). By using 2D mesoporous carbon sandwiched MXene (MCSMx) nanosheets as dual functional substrates, Co single atoms (Co-SA) were confined within MCSMx (CoSA/MCSMx), in which the coordinated Co-N4 sites in highly ordered mesoporous channels (∼10 nm) facilitated the adsorption of peroxymonosulfate (PMS), while the excellent conductivity of MXene as the substrate enhanced the transport of electron. The unique design of Co-SA anchored on dual carriers endows the CoSA/MCSMx with excellent PMS adsorption and rapid electron transfer, achieved nearly 100 % ETP pathway for bisphenol A (BPA) removal and highly selective degradation towards electron-rich pollutants. Moreover, the ETP-induced polymerization transfer reaction of BPA was discovered in the catalytic system, resulting in total organic carbon (TOC) removal ratios of up to 72 %. This work provides new insights into the rational design ETP-based systems for the efficient removal of organic pollutants.

Metatranscriptomic Analysis Reveals Synergistic Activities of Comammox and Anammox Bacteria in Full-Scale Attached Growth Nitrogen Removal System.

Leveraging comammox Nitrospira and anammox bacteria for shortcut nitrogen removal can drastically lower the carbon footprint of wastewater treatment facilities by decreasing aeration energy, carbon, alkalinity, and tank volume requirements while also potentially reducing nitrous oxide emissions. However, their co-occurrence as dominant nitrifying bacteria is rarely reported in full-scale wastewater treatment. As a result, there is a poor understanding of how operational parameters, in particular, dissolved oxygen, impact their activity and synergistic behavior. Here, we report the impact of dissolved oxygen concentration (DO = 2, 4, 6 mg/L) on the microbial community's transcriptomic expression in a full-scale integrated fixed film activated sludge (IFAS) municipal wastewater treatment facility where nitrogen removal is predominantly performed by comammox Nitrospira and anammox bacterial populations. 16S rRNA transcript compositions revealed anammox bacteria and Nitrospira were significantly more active in IFAS biofilms compared to suspended sludge biomass. In IFAS biofilms, anammox bacteria significantly increased hzo expression at lower dissolved oxygen concentrations and this increase was highly correlated with the amoA expression levels of comammox bacteria. Interestingly, the genes involved in nitrite oxidation by comammox bacteria were significantly more upregulated, relative to the genes involved in ammonia oxidation with decreasing dissolved oxygen concentrations. Ultimately, our findings suggest that comammox Nitrospira supplies anammox bacteria with nitrite via ammonia oxidation and that this synergistic behavior is dependent on dissolved oxygen concentrations.

Pain experience with outpatient hysteroscopy: A prospective cohort study

BackgroundAbnormal uterine bleeding (AUB) affects women of all ages and is one of the most common reasons for referral to a gynaecological clinic. Operative hysteroscopic procedures allow for a see-and-treat approach to AUB, and these techniques have been shown to be feasible and acceptable in the outpatient setting. ObjectiveTo assess if there is an increase in pain scores for women who are undergoing an operative hysteroscopic procedure with Myosure LITE® (Hologic; mechanical hysteroscopic tissue removal system) compared to outpatient diagnostic hysteroscopy alone. Study designA prospective cohort study was performed. All participants attending the outpatient hysteroscopy clinic at Mercy Hospital for Women completed a pre-and post-procedure questionnaire. This included a visual analogue scale (VAS) for any pre-existing pain, anticipated pain, and actual pain experienced during procedure. Factors influencing overall satisfaction and willingness to attend again were also assessed. Data was entered into RedCap® for analysis. A difference in VAS of 10 mm or more was considered clinically significant. An alpha of p < 0.05 was assigned for statistical significance. ResultsBetween February 2020 and November 2022, 208 women underwent outpatient diagnostic hysteroscopy followed by an operative hysteroscopy with MyoSure®. To allow for standardisation of analgesia, only participants who had a cervical block before their Myosure® procedure were included for analysis (n = 111). There was statistical evidence (t(111) = 2.36, p = 0.02) of a lower mean VAS pain score for operative Myosure (36.5 mm, 95 % CI: 31.1–41.8 mm) compared to outpatient diagnostic hysteroscopy (44.1 mm, 95 % CI: 39.0–49.2 mm). The mean difference in VAS pain score was estimated as 7.7 mm (95 % CI: 1.2–14.1 mm) lower for Myosure compared to hysteroscopy. Given the threshold for clinical significance was considered as 10 mm difference in VAS, the variance in pain scores is under the likely clinically significant range. There was no significant difference in pain scores for diagnostic hysteroscopy with or without paracervical block (mean difference = 1.42; 95 % CI: −6.35 to 9.20). There was no association between pre-existing pain, and actual pain for hysteroscopy, or Myosure (p = 0.997 and p = 0.065 respectively). The anticipated pain score was weakly associated with actual pain during the operative Myosure procedure (p = 0.02), and with outpatient diagnostic hysteroscopy (p = 0.019). ConclusionOutpatient hysteroscopy procedures are generally well tolerated. The pain experience with operative Myosure was less than that reported during the diagnostic hysteroscopy by the same patient although this is unlikely of clinical significance. Importantly, Myosure was not more painful than the initial diagnostic procedure, and most patients were satisfied with the outcome and would choose to have the procedure again in an outpatient setting. This is in keeping with other studies which have shown a high degree of patient tolerance and satisfaction with this approach.

An active learning approach for reliability assessment of passive systems combining polynomial chaos expansion and adaptive sampling

Passive safety system is extensively employed in newly designed reactors to increase their inherent safety. However, the driving force is smaller, and the uncertainty of the thermal–hydraulic (T-H) process may potentially result in the inability of system to perform its intended function, which is often known as functional failure. Therefore, the passive systems reliability has received increasing attention. Unfortunately, the assessment of system failure probability utilizing Monte Carlo simulation (MCS) methods necessitates a significant quantity of repeated calculations employing the thermal–hydraulic code, which may be impractical in terms of computational cost. To enhance the assessment calculation efficiency, an adaptive surrogate model is proposed. The bootstrap method was employed to introduce an error estimate into the polynomial chaos expansion (PCE) model, which solves the obstacle of the PCE model in reliability evaluation applications due to the lack of error estimation. The method constructs an active learning approach through error estimation, strategically identifies and selects the best candidate samples, and iteratively updates the initial experimental design. The effectiveness of the method was verified through three benchmark cases, and it was employed for assessing the passive residual heat removal system (PRHRS) reliability within integral-type pressurized water reactor (IPWR200). The results demonstrated that the proposed method significantly diminishes the frequency of invocations to the T-H code and improves computational efficiency to a large extent. Furthermore, it can serve as a valuable guide for the design, operation, and reliability evaluation of the passive system.

Enhancement of Biological Nitrogen Removal System Resilience to Chronic Exposure of Zinc Oxide Nanoparticles by Quorum Sensing Modulation: Physiochemical, Microbial, and Metabolic Insights

The effects of three typical N-acyl-homoserine lactones (AHLs) on the tolerance of biological nitrogen removal (BNR) system to chronic exposure of zinc oxide nanoparticles (NPs) were investigated. C4-HSL successfully delayed the crash time of nitrogen removal performances in the NP-stressed system, while C6-HSL and C10-HSL maintained total nitrogen removal efficiencies throughout the 90-day NP exposure. All three AHLs increased NPs’ contents captured in extracellular polymeric substances, alleviating membrane damage and preserving floc structure. The activities of tricarboxylic acid cycle-related enzymes and the relative abundances of BNR-related functional genes and genera were significantly enhanced. Besides, C6-HSL and C10-HSL augmented antioxidant enzyme activities and the abundances of functional genes and metabolites related to antioxidation, flagellar assembly, and chemotaxis, which synergistically reduced the reactive oxygen species’ excessive accumulation. The tested AHLs effectively enhanced BNR systems’ tolerance to chronic NP exposure, providing inspiration for quorum sensing applications in emerging contaminant removal.

Importance of iron complexation and floc formation towards phosphonate removal with Fe–electrocoagulation

Phosphonates are widely used scale inhibitors, but the residual phosphonates in drainage are challenging to remove because of their chelating capacity and resistance to biodegradation. Here, we reported a highly efficient and robust Fe-electrocoagulation (Fe-EC) system for phosphonate removal. Surprisingly, we found for the first time that phosphonates like NTMP were more efficiently removed under anoxic conditions (80% of total soluble phosphorus (TSP) in 4 min) than oxic conditions (0% of TSP within 6 min) in NaCl solution. A similar phenomenon was observed when other phosphonates, such as EDTMP and DTPMP, were removed, highlighting the importance of iron complexation and floc formation toward phosphonate removal with Fe-EC. We also showed that the removal efficiency of NTMP by electrochemically in-situ formed flocs (97%) was much higher than post-adsorption systems (ex-situ, 40%), revealing that the growth of flocs consumed the active site for NTMP adsorption. Beyond the removal of TSP, 10 % of NTMP-P was also degraded after the electrolysis phase, evidenced by the evolution of phosphate-P. However, this did not happen in anoxic or chemical coagulation processes, which confirms the formation of reactive oxygen species via Fe(II) oxidation in the oxic Fe-EC system. The primary removal mechanism of phosphonates is due to their complexation with iron (hydr)oxide generated in the Fe-EC system by forming a Fe-O-P bond. Encouragingly, the Fe-EC system exhibits comparable or even better performance in treating phosphonate-laden wastewater (i.e., cooling water). Our preliminary cost calculation suggests the proposed system (€ 0.009/m3) has a much lower OPEX under oxic conditions than existing approaches. This study sheds light on the removal mechanism of phosphonate and the treatment of phosphonate-laden wastewater by playing with the iron complexion and flocs formation in classical Fe-EC systems.

Impact of the redox-active MnTnHex-2-PyP5+ and cisplatin on the metabolome of non-small cell lung cancer cells

Redox-based cancer therapeutic strategies aim to raise reactive oxygen species (ROS) levels in cancer cells, thus modifying their redox status, and eventually inducing cell death. Promising compounds, known as superoxide dismutase mimics (SODm), e.g. MnTnHex-2-Py5+ (MnTnHex), could increase intracellular H2O2 in cancer cells with deficient ROS removal systems and therefore enhance radio- and chemotherapy efficacy. We have previously shown that MnTnHex was cytotoxic either alone or combined with cisplatin to non-small cell lung cancer (NSCLC) cells. To gain a deeper understanding of the effects and safety of this compound, it is crucial to analyze the metabolic alterations that take place within the cell. Our goal was thus to study the intracellular metabolome (intracellular metabolites) of NSCLC cells (A549 and H1975) using nuclear magnetic resonance (NMR) spectroscopy-based metabolomics to evaluate the changes in cellular metabolism upon exposure to MnTnHex per se or in combination with cisplatin. 1H NMR metabolomics revealed a higher number of significantly altered metabolites in A549 cells exposed to MnTnHex alone or combined with cisplatin in comparison with non-treated cells (nine dysregulated metabolites), suggesting an impact on aminoacyl-tRNA biosynthesis, glycolysis/gluconeogenesis, taurine, hypotaurine, glycerophospholipid, pyruvate, arginine and proline metabolisms. Regarding H1975 cells, significant alterations in the levels of six metabolites were observed upon co-treatment with MnTnHex and cisplatin, suggesting dysregulations in aminoacyl-tRNA biosynthesis, arginine and proline metabolism, pyruvate metabolism, and glycolysis/gluconeogenesis. These findings help us to understand the impact of MnTnHex on NSCLC cells. Importantly, specific altered metabolites, such as taurine, may contribute to the chemosensitizing effects of MnTnHex.

Development of OPR1000 RCS Hot-leg surge nozzle thermal sleeve remote removal system

The OPR1000-type reactor incorporates seven thermal sleeves (T/S) within the reactor cooling system (RCS) piping line, constructed from Inconel-600 or Inconel-690 material, depending on the power plant. In instances involving T/S made of Inconel-690 material, certain issues were identified either initially or at the commencement of operations. Consequently, the T/S installed on the safety injection nozzle was promptly removed. However, the T/S affixed to the hot-leg surge nozzle remained in operation without removal. Subsequent ultrasonic testing, conducted as part of the scheduled preventive maintenance period, revealed that the T/S associated with the hot-leg surge nozzle in the RCS pipe exhibited protrusions attributable to eccentricity and groove wear. Consequently, the removal of the T/S became imperative. This study delineates the development timeline of a remote system and highlights significant milestones achieved in the removal of the hot-leg surge nozzle T/S during the planned preventive maintenance period.

Thermal-hydraulic characterization of a 50-kW medicinal-aimed aqueous homogeneous reactor (MAHR)

This paper analyses the thermal–hydraulic performance of a proposed 50-kW aqueous homogeneous reactor (AHR) aimed at producing Mo-99. The reactor thermal–hydraulic characteristics are analyzed using ANSYS-FLUENT software and Relap code, and the results are validated through experiments conducted by a prototypic cylindrical sector of the reactor vessel. Boundary conditions in the CFD simulation are set up based on Relap modelling, while CFD outputs are validated by experimental results achieved using the laboratory model. Then, various parameters, including coolant mass flow rate, first cycle pipe diameter, coolant outlet temperature, average fuel solution temperature, and the elevation difference between the reactor and heat exchanger, are optimized using the least-squares optimization method. Results demonstrate that the heat removal system provides sufficient cooling capacity to ensure stable operation of the proposed AHR core by preventing fuel solution overheating and, consequently, boiling (void formation) in the active fuel solution.

Analysis of the hydrogen safety of the NPP with a VVER-1200/V-491 reactor in a severe beyond design based accident

The results of a computational analysis of possible modes of combustion of a hydrogen-air mixture in containment during the evolution of a severe beyond design basis accident (BDBA) with the COCOSYS code are presented. The containment of the NPP with a VVER-1200/V-491 reactor was selected as the object of study. BDBA with loss of coolant occurs due to a break of the injection pipeline of the pressurizer system (LOCA DN179) and the simultaneous failure of all active channels of the emergency core cooling system (ECCS). The calculated parameters of the thermodynamic state (pressure and temperature) of the gas mixture are given, and the values of the concentration distribution of hydrogen inside the containment are presented. After calculating the hydrogen distribution and mixing in all compartments of the containment, an evaluation was made of the flammability of the mixture and the potential for self-ignition in the containment by using a three-component Shapiro-Moffette diagram. It was concluded that in BDBA (LOCA DN179 with failure of active ECCS) detonation of the hydrogen-containing mixture is excluded, and deflagration is possible only in the emergency compartment of steam generators with a pipeline break. Thus, the hydrogen risk mitigation has been achieved in accordance with the standards established by the Belarusian regulator, provided that the localization safety systems are operational in the event of hydrogen deflagration. And the efficiency of the hydrogen removal system from the containment using catalytic recombination is considered sufficient for the considered BDBA.

Electrospinning and Partial Etching Behaviors of Core-Shell Nanofibers Directly Electrospun on Mesh Substrates for Application in a Cover-Free Compact Air Filter.

The exposure of workers to propylene glycol monomethyl ether acetate (PGMEA) in manufacturing environments can result in potential health risks. Therefore, systems for PGMEA removal are required for indoor air quality control. In this study, core-shell zeolite socony mobil-5 (ZSM-5)/polyvinylpyrrolidone-polyvinylidene fluoride nanofibers were directly electrospun and partially wet-etched on a mesh substrate to develop a cover-free compact PGMEA air filter. The electrospinning behaviors of the core-shell nanofibers were investigated to optimize the electrospinning time and humidity and to enable the manufacture of thin and light air-filter layers. The partial wet etching of the nanofibers was undertaken using different etching solvents and times to ensure the exposure of the active sites of ZSM-5. The performances of the ZSM-5/PVDF nanofiber air filters were assessed by measuring five consecutive PGMEA adsorption-desorption cycles at different desorption temperatures. The synthesized material remained stable upon repeated adsorption-desorption cycles and could be regenerated at a low desorption temperature (80 °C), demonstrating a consistent adsorption performance upon prolonged adsorption-desorption cycling and low energy consumption during regeneration. The results of this study provide new insights into the design of industrial air filters using functional ceramic/polymer nanofibers and the application of these filters.

Natural eutectic solvents and graphene integrated within emulsion liquid membrane system for sodium removal from crude biodiesel

This study reports a new technique for sodium ion removal from biodiesel using a green emulsion liquid membrane (GELM) system based on natural deep eutectic solvents (NADESs) and graphene. The DES consists of choline chloride with glycerol and lactic acid, and tetramethylammonium chloride with glycerol and lactic acid. COSMO-RS software was used to compute the intermolecular interaction of sodium with hydrogen bond acceptors and donors of the NADES. The simulation shows that NADES was the most effective stripping phase for sodium ion removal, which follows the experimental results. The investigation on the stability of ELM and sodium (830 ppm of initially) extraction efficiency showed that the GELM-NADES technique can achieves a sodium ion extraction efficiency of 99.6 % (3.17 ppm) with high stability at a homogenization speed of 8000 rpm, homogenization time of 3 min, HBA: HBD molar ratio of 1:4, 3 wt% of span 80, 10 minutes of extraction time, 400 rpm stirring speed and 0.5 treatment ratio. The presence of graphene (0.3 g) in the system further enhanced the efficiency and shortened the required extraction time from 6 to 4 min to meet the ASTM D6752 standards. The transport mechanism of sodium ions into the ELM phases adheres to the first-order kinetics model and film theory mechanisms. The overall mass transfer coefficient KO, mass transfer coefficient of the external phase in agitated reactor KM, and interfacial reaction rate constant KF of 5.188×10−9,1.373×10−7,and 5.392×10−9 m/s, respectively. ELM system with NADES and graphene can provide a cleaner route for biodiesel downstream processing.

Coupled effects of Fenton-like systems with different concentrations of H2O2/Biochar on diethyl phthalate removal: Dominant role of environmental persistent free radicals (EPFRs)

To investigate the impact of different H2O2 concentrations on the Fenton-like systems of H2O2/biochar, this study examined the mechanism of the physical structure and environmental persistent free radicals (EPFRs) of biochar during diethyl phthalate (DEP) removal by the Fenton-like system. The peak-splitting method was utilized to differentiate EPFRs types in cotton stalk biochar produced at different temperatures. High-temperature environments promote π-electron delocalization, which facilitates phenyl π free radicals and σ-π oxygen-containing free radicals. By analyzing relationships between the removal rate K1 and removal constant Kobs of DEP with the structural properties of biochar, it was discovered that EPFRs concentrations in biochar had a significant positive correlation with K1 (r = 0.92) and Kobs (r = 0.97). Different H2O2 concentrations added to the biochar removal system resulted in varied DEP removal efficiency. Among them, CS500, CS550, and CS600 exhibited superior DEP removal efficiency when H2O2 concentration was 5 mM.

Development of improved spray system with effective electrical electrodes for aerosol removal: An experimental study in UTARTS facility

Safe reactor decommissioning, especially for damaged Fukushima Daiichi (1F) nuclear power plants, is vital for environmental safety. Key challenges include remotely cleaning radiation hotspots and cutting fuel debris within the damaged primary containment vessel. However, submicron radioactive Aerosol Particles (APs) can be generated, thus necessitating effective aerosol control and removal to avoid radioactive environmental pollution and reduce radiation exposure risks during 1F decommissioning. Flue gases containing submicron APs that result in environmental pollution can also generated from other industrial works, e.g., coal, mining and chemical sectors. Conventional water spray is difficult to scavenge these small APs. Although previous studies showed the effectiveness of charged droplets on accelerating aerosol removal, the charging configuration is also important to scavenging performance. Hence, this study performs aerosol scavenging experiments in our UTARTS facility with varying induction electrode designs. Experimental results show the saturation of scavenging efficiency at high voltage and indicate the importance of charging polarity. Moreover, proper configurations of electrode position, geometry and material are studied and discussed. Our findings can be beneficial for the improvement of spray system for aerosol removal to mitigate radioactivity release and minimize contaminated water production and have implications for gas purification in various environmental and chemical industries.

Effect of Two Techniques of Separated File Removal Systems on Dentin Loss and Fracture Resistance of Teeth (In Vitro Study)

Effect of Two Techniques of Separated File Removal Systems on Dentin Loss and Fracture Resistance of Teeth (In Vitro Study)

Refusing Child-Stealing States: Settler Capitalism and the Ends of Canada's Indigenous Child Removal System

Abstract: This article examines the relationship between Canadian sovereignty and the removal of Indigenous children into non-native foster and adoptive homes. In it, I analyze how colonial child protection regimes following Residential Schools—from the Sixties Scoop (1951–1991) to the present Millennium Scoop—continue Canada's war against Indigenous lives and nations. From Sixties Scoop survivor narratives, ethnographic and archival data, and Indigenous and Black feminist theory, I highlight the gendered character of colonial sovereignty and capitalism. This paper argues that daily practices of refusal and care as an elaboration of Indigenous political orders unmake the grounds of colonial polity.

A novel solar-aided NOx removal system in peaking power plants

Solar–coal hybrid power generation achieves the production of efficient, clean, and low-carbon electricity. The association between solar heat and selective catalytic reduction NOx removal (SCR de-NOx) can lead to the development of a novel solar-aided NOx removal system for peaking power plants. In this study, a novel system was proposed, in which large amount of flat-plate and small amount of trough solar energies were integrated to optimise the SCR de-NOx and energy utilisation in the boiler tail. Thermodynamic, NOx removal, and economic analyses were performed. For a typical peaking unit, the proposed system produced 14.6 MWe of solar-generated electric power and exhibited a high solar-to-electricity efficiency of 30.15 %. The integrated solar heat significantly increased the SCR de-NOx temperature and NOx removal efficiency. Based on its outstanding solar conversion performance, the proposed system achieved a net annual benefit (NAB) of 24.01 million Chinese yuan (CNY) and maintained a low cost of solar-generated electricity (COEs) of 0.56 CNY/kWh. Based on cascade utilisation of solar thermal energy, the proposed system achieved high performance under all loads and significantly improved the NOx removal performance under low and medium loads, especially for peaking power plants.

Smart solar maintenance: IoT-enabled automated cleaning for enhanced photovoltaic efficiency

This innovative project aims to increase the effectiveness and user experience of solar panel systems by introducing a state-of-the-art dust and speck removal system. Leveraging cutting-edge technology, the system demonstrates a remarkable 32% increase in power output compared to dirty solar panels. The approach is characterized by its reliance on the universe as the system controller, reducing the need for manual intervention and minimizing the workforce required for panel cleaning. The proposed timed system utilizes water and wipers, facilitated by internet of things (IoT) technology, microcontrollers, and sensor modules for efficient and automated operation. An Android application provides user control and notifications about ongoing processes. The system’s adaptability for various settings is emphasized, offering a portable solution. The smart IoT based automatic solar panel cleaning ensures reliable performance, underscoring the project’s commitment to improve scalability, cost-efficiency, performance, integrity, and consistency.

Experimental Setup and Mathematical Modeling of Cutting Parameters for Water Hyacinth Removal Systems: Optimizing Specific Power Consumption and Cutting Efficiency

Experimental Setup and Mathematical Modeling of Cutting Parameters for Water Hyacinth Removal Systems: Optimizing Specific Power Consumption and Cutting Efficiency

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.