Search Results (144)

Developing ultra-high-temperature geothermal resources is challenging, as traditional drilling fluids, including foam systems, lack thermal stability above 160 °C. To address this key technical bottleneck, this study delves into the screening principles for high-temperature-resistant foaming agents and foam stabilizers. Through high-temperature aging experiments (foaming performance evaluated up to 240 °C and rheological/filtration properties evaluated after aging at 200 °C), specific additives were selected that still exhibit good foaming and foam-stabilizing performance under high-temperature and high-salinity conditions. Building on this, the foam drilling fluid system formulation was optimized using an orthogonal experimental design. The optimized formulations were systematically evaluated for their density, volume, rheological properties (apparent viscosity and plastic viscosity), and filtration properties (API fluid loss and HTHP fluid loss) before and after high-temperature aging (at 200 °C). The research results indicate that specific formulation systems exhibit excellent high-temperature stability and particularly outstanding performance in filtration control, with the selected foaming agent FP-1 maintaining good performance up to 240 °C and optimized formulations demonstrating excellent HTHP fluid loss control at 200 °C. This provides an important theoretical basis and technical support for further research and field application of foam drilling fluid systems for deep high-temperature geothermal energy development. Full article

We quantified the bioactive compounds of Ethiopian coffee (ETH), spent coffee grounds SCGs from ETH (SCG-ETH), and mixed SCGs (SCG-MIX) prepared by filtration methods and investigated the effect of SCG-ETH on ruminal fermentation as well as the anthelmintic activity of ETH. Three substrates, meadow hay (MH)-barley grain (MH-BG), MH-SCG-ETH, and BG-SCG-ETH (1:1 w/w), were fermented using an in vitro gas production technique. The bioactive compounds were quantitatively analyzed using ultra-high-resolution mass spectrometry. We performed an in vitro larval development test to determine the anthelmintic effect of an aqueous extract of ETH against the gastrointestinal nematode (GIN) Haemonchus contortus. The total content of bioactive compounds was highest in SCG-ETH, followed by SCG-MIX and ETH (35.2, 31.2, and 20.9 mg/g dry matter, respectively). Total gas and methane production (p < 0.001) were decreased by both MH-SCG-ETH and BG-SCG-ETH. The in vitro digestibility of dry matter was higher for MH-SCG-ETH and BG-SCG-ETH than for MH-BG. The aqueous ETH extract exhibited a strong larvicidal effect, with a mean lethal dose of 13.2 mg/mL for 50% mortality and 31.9 mg/L for 99% mortality. SCG substrates have the potential to modulate ruminal fermentation and serve as a source of anthelmintic bioactive compounds against GINs in ruminants. Full article

This study aimed to produce invertase with characteristics comparable to commercial formulations using a low-cost raw material, employing environmentally friendly extraction and refinement methods. Sifted yeast, the residual baker’s yeast in industrial production, was used as raw material, and invertase in the yeast cell was extracted by ultrasonication and purified by micro- and ultra-filtration (MF and UF) methods. Subjecting the crude enzyme extract to MF followed by UF resulted in increased activity and specific activity. Through this process, the enzyme activity increased from 153 IU/mL to 691 IU/mL. The purified enzyme was lyophilized and the production of invertase at the laboratory scale was accomplished. The obtained enzyme was found to be stable at pH 5 and within the temperature range of 30–40 °C. It retained its activity for 60 days at −18 °C, whereas a 20% loss in activity was observed at +4 °C over the same period. As a result, it was demonstrated that invertase enzyme can be produced from a low-cost raw material which is considered as waste in the industry. To pass to the commercial production stage, processing of higher amounts of raw material by preventing foaming and heating problems in ultrasonication and scale-up studies testing the permeability properties of different membrane systems at a pilot-scale are necessary. Full article

The growing presence of organic micropollutants (OMPs) in water sources is a major health concern. Successful removal of OMPs from water sources and ensuring the cleanliness of drinking water has become an important topic in recent years. In this study, 15 nanofiltration (NF) and reverse osmosis (RO) commercial membranes were selected and their potential to remove 10 frequently encountered OMPs in drinking water, with systematically different chemical characteristics, was evaluated. To quickly identify the most promising membranes, high throughput dead-end filtrations were initially conducted. Subsequently, the 4 best performing membranes were used in a more relevant high-throughput cross-flow filtration. Membrane performance was evaluated by analyzing OMP concentrations in the feed and retentates of the different membranes using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). This study identified NF 90 (Dow), NF 270 (Dow), NFX (Synder) and TS80 (Trisep) as membranes with superior performance, with a permeance between 3 and 7 L.${\mathrm{m}}^{-2}$.h⁻¹.bar⁻¹ and retentions that were generally around 90%, except for NFX which showed slightly lower retentions. Full article

This study explores the application and robustness of an adaptive optimal control (AOC) strategy to optimize the operation of membrane filtration systems. The proposed control is based on a constant flux model where fouling is primarily due to cake layer formation. The algorithm dynamically finds the optimal ratio between the filtration (F) and backwash (BW) time ratio in response to system disturbances, thereby adapting the operational state of the membrane in order to optimize its performance in terms of energy consumption. The strategy was successfully applied to both microfiltration (MF) and ultrafiltration (UF) systems and quantitatively demonstrated its effectiveness in reducing energy consumption and controlling fouling. It proved robust against model uncertainties and demonstrated real-time adaptability even under varying and realistic disturbance conditions. The implementation of this control strategy facilitated real-time adaptation of the filtration/backwash (F/BW) ratio in response to dynamic system disturbances. The result underlines that the control behavior is predominantly driven by fluctuations in mixed liquor suspended solids (MLSSs). Compared to conventional fixed-time modes, the AOC led to significant energy savings, ranging from 7% to 30%, and membrane lifespan extension, mainly through more efficient permeate pump usage. Full article

This paper applies a semi-quantitative approach to review the diversity, environmental controls, detection methods, human health risks, and mitigation of cyanotoxins in drinking water systems (DWSs). It discusses the environmental factors controlling the occurrence of cyanotoxins, presents the merits and limitations of emerging methods of their detection (qPCR, liquid chromatography–mass spectrometry, and electrochemical biosensors), and outlines the human exposure pathways and health outcomes with identification of high-risk groups and settings. High-risk groups include (1) communities relying on untreated drinking water from unsafe, polluted water sources and (2) low-income countries where cyanotoxins are not routinely monitored in DWSs. The fate and behavior processes are discussed, including removing cyanotoxins in DWSs based on conventional and advanced treatment processes. The available methods for cyanotoxin removal presented in this paper include (1) polymer-based adsorbents, (2) coagulation/flocculation, (3) advanced oxidation processes, (4) ultra- and nanofiltration, and (5) multi-soil layer systems. Future research should address (1) detection and fate in storage and conveyance facilities and at the point of consumption, (2) degradation pathways and toxicity of by-products or metabolites, (3) interactive health effects of cyanotoxins with legacy and emerging contaminants, (4) removal by low-cost treatment techniques (e.g., solar disinfection, boiling, bio-sand filtration, and chlorination), (5) quantitative health risk profiling of high-risk groups, and (6) epidemiological studies to link the prevalence of human health outcomes (e.g., cancer) to cyanotoxins in DWSs. Full article

Sample pretreatment is one of the most important steps in guaranteeing the success of a chromatographic analysis. The selected methodology must ensure simultaneously that a sample is “clean” enough for analysis and that the target analytes are not removed in the process. This can be especially difficult when working with complex matrices such as natural waters and wastewater. For pharmaceutical active compounds (PhACs) analysis by solid-phase extraction (SPE) followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), and due to the high level of organic matter in wastewater, the water samples are filtered consecutively through three filters, a paper filter, a glass microfiber filter of 1 µm, and a Nylon filter of 0.45 µm. This filtration allows the sample’s passage through the SPE cartridge to be faster, and there is no cartridge clogging, allowing for greater efficiency in the adsorption process. The big question is whether the PhACs are eliminated during filtration, since they may be adsorbed to organic matter. This work aimed to determine if the best approach for quantifying PhACs in wastewater and surface waters would be to filter them prior or to perform SPE directly. Both approaches analyzed a total of 26 PhACs. Turbidity (TUR) and permanganate index (PI) were determined, and their values were high for samples with a high organic matter content. A statistical analysis was performed to determine the best approach to treat these water samples and whether any correlation existed between PhAC concentrations, PI, and TUR. The PhAC quantification shows a positive correlation with TUR and a negative correlation with PI for most of the target PhACs. However, there are not significantly different results for filtered and not-filtered wastewater samples. Full article

Ultra-high-efficiency filter media ensure high air cleanliness but need periodic replacement due to pressure drop increase. Adding a pre-filter can extend the filtration system’s service lifetime, yet the pre-filter and main-filter matching lacks systematic study. This research explored how different filter media combinations affected a two-stage ultra-high-efficiency filtration system’s performance. This study focused on five pre-filter grades (F7–F9, H10, H11) and two different types of main-filter media, fiberglass and composite. It was found that the F8 pre-filter media had the best effect on extending the service lifetime of BX and BX + PTFE. The service lifetimes were extended from 44 min and 70 min to 231 min and 326 min, respectively, reaching 5.25 times and 4.65 times the original lifetime. Moreover, the optimal pre-filter grade was less affected by the initial resistance of the main filter. Meanwhile, the BX + PTFE filtration system always showed a longer service lifetime and dust holding capacity compared to the BX filtration system. This study provides guidance for the design and combination of two-stage filters in the context of high-cleanliness applications as well as the improvement of multi-stage filter performance in building ventilation. Full article

To mitigate the environmental effects of oil spills, a novel hydrophilic–oleophobic mixed-coated filter was developed for efficient oil–water separation and surface oil recovery. The coating consisted of titanium dioxide nanoparticles (TiO₂) and ultra-fine carbon black powder, deposited onto a 304 stainless-steel mesh substrate via spray deposition, followed by high-temperature sintering. This process induced a phase transition in TiO₂ from anatase to rutile, and formed a TiC khamrabaevite. The filter’s performance was evaluated using contact angle measurements and filtration tests with a motor oil–water mixture, while SEM, EDS, and XRD analyses characterized its morphology and coating structure. Contact angle testing confirmed that carbon modification significantly enhanced the oleophobicity of the TiO₂ filter, and SEM imaging demonstrated higher substrate coating adhesion, enabling multiple reuse cycles. These findings highlight the potential of TiO₂ carbon composite coatings in improving oil spill remediation technologies by offering a reusable and efficient filtration system. Full article

Chronic kidney disease (CKD) has become one of the most rapidly advancing diseases of the century, contributing significantly to increased mortality and morbidity. Metabolomics presents a promising approach to understanding CKD pathogenesis and identifying novel biomarkers for early diagnosis. This study evaluated serum and urine metabolomic profiles in CKD patients with declining glomerular filtration rates (eGFR). Using targeted metabolomics, we quantified seven potential metabolites in blood and urine samples from 20 healthy individuals and 99 CKD patients staged by eGFR according to the KDIGO guidelines. The analysis was conducted using ultra-high performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry. The metabolites investigated included L-phenylalanine, L-methionine, arginine, indoxyl sulfate, kynurenic acid, and L-acetylcarnitine. Quantitative assessments were performed using pure standards and validated through methods such as the limit of detection (LOD) and limit of quantification (LOQ). The findings identified potential biomarkers for early CKD diagnosis: in serum, L-phenylalanine, L-methionine, arginine, kynurenic acid, and indoxyl sulfate, while L-acetylcarnitine was significant in urine. These biomarkers could provide valuable insights into CKD progression and support in developing more effective diagnostic tools for early intervention. Full article

Water-based drilling fluids (WBDFs) cannot be effectively applied in long horizontal wells, such as shale gas wells, due to their high coefficient of friction (COF) and filtration loss that can strongly limit the efficient and environmentally friendly development of oil and gas resources. The objective of this study is the formulation of a WBDF characterized by ultra-low friction and ultra-low filtration properties, with a high-concentration polyepoxysuccinic acid (PESA) solution being utilized in the continuous phase. The research aims at the exploration of the feasibility of the method, the validation of the results, and the elucidation of the underlying mechanisms. The experimental results confirmed that the proposed WBDFs have excellent rheological properties, a COF of 0.016 and an API filtration of 0.4 mL. Microscopic analysis confirmed a direct and positive correlation between the macroscopic properties of the drilling fluids and their adsorption behavior at high PESA concentrations. This approach can be used to redesign traditional WBDFs and provide new possibilities to realize super performance in WBDFs that can be used to replace oil-based drilling fluids. Full article

The application of membrane filtration, particularly micro- and ultra-filtration, in food and pharmaceutical industries often faces the issue of protein fouling. In this study, we aimed to fabricate a free-standing ternary tungsten trioxide/carbon nanotube/zinc oxide (WO₃/CNT/ZnO)–chitosan composite photocatalytic membrane via wet processing and infiltration techniques to address the fouling issue. Infiltration with low molecular weight chitosan was found to enhance the mechanical stability of the ternary composite photocatalytic membrane. The ternary composite photocatalytic membrane with a 0.16 g ternary photocatalyst load demonstrated 86% efficiency in the degradation of bovine serum albumin (BSA) under sunlight irradiation for 120 min. A reduction in permeation flux accompanied by an increase in BSA rejection was observed as the loading of the ternary photocatalyst in the ternary composite photocatalytic membrane was increased. This can be associated with the decreased average porosity and mean pore radius. The ternary composite photocatalytic membrane demonstrated reasonably good antifouling behavior with an R_fr of 82% and an R_if of 18%. The antifouling property demonstrated by the ternary composite photocatalytic membrane is important in maintaining the reusability of the membrane. Full article

The valorization of ultra-concentrated seawater brines, named bitterns, requires preliminary purification processes, such as membrane filtration, before they can be fully exploited. This study investigates the performance of an ultrafiltration pilot plant aimed at separating organic matter and large particles from real bitterns. An empirical model for the bittern viscosity was developed to better characterize the membrane. Distinct variations in permeability, fouling resistance and rejection coefficient were observed under operational pressures ranging from 2 to 4 bar. Working at low pressure (2 bar), the pilot plant achieves permeability and rejection coefficient values of 17 L/m²hbar and 95%, respectively. Foulant behavior was characterized by determining a “fouling resistance”, obtaining an average value of ${10}^{13}$ m⁻¹. Tests with three distinct bittern samples were conducted to assess the influence of chemical composition and organic matter content on membrane permeability and fouling characteristics. The collected data enabled a comprehensive characterization of the ultrafiltration pilot unit working with this particular saline feed solution, which has very high technical–economic potential. Full article

The salt fractions of milk consist of cations (e.g., Ca, Mg, and Na) and anions (e.g., phosphate, citrate, and chloride). These salts are present as free ions or in complexes with other ions or proteins, primarily the caseins. Furthermore, significant levels of Ca and phosphate are also found in insoluble form, inside the casein micelles. The distribution of salts between this micellar phase and the soluble phase is important for the stability and properties of milk and dairy products. Various processes, such as (ultra-)centrifugation, (ultra-)filtration, dialysis, and selective precipitation have been used to separate the micellar and soluble phases in milk and dairy products to allow for studying the salts’ distribution between these phases. These different methods can lead to different levels of soluble salts because the salts in the supernatant from centrifugation, the permeate from ultrafiltration, and the diffusate from dialysis can differ notably. Hence, understanding which components are fractionated with these techniques and how this affects the levels of the soluble salts determined is critical for milk and dairy products. Applying the aforementioned methods to cheese products is further challenging because these methods are primarily developed for fractionating the soluble and micellar phases of milk. Instead, methods that analyze salts in water-soluble extracts, or soluble phases expressed from cheese by pressing or centrifugation are typically used. This review focuses on the significance of salt distribution and variations in salt fractions obtained using different methodologies for both milk and cheese. Full article

The removal of particulate matter (PM) from air streams is essential for advancing environmental technologies and safeguarding public health. This study explores the performance of an electrostatic precipitator (ESP) in eliminating fine and ultra-fine PM under varied experimental conditions. It uniquely examines the influence of PM size and feed rate on ESP removal efficiency. The system’s use of low voltages enhances energy sustainability, while its innovative design improves corona discharge, leading to significant reductions in fine and ultra-fine PM emissions. Plants using electrical devices are increasingly being incorporated into material processing lines to reduce pollution in the surrounding work area, as well as to collect particle emissions in the atmosphere. It is also possible to recycle some raw materials in this way with low energy consumption. This cleaning technology increases the added value of industrial equipment, which affects its competitiveness and its impact on sustainable manufacturing. The experimental results indicate a steady electrostatic field voltage of 15.1 kilovolts, with an airflow maintained at 0.8 m/s through a doser at 2.5 bar, eliminating the need for a fan. The PM feed rate varied between 2 and 20 mm/h, with six trials conducted to ensure the data were consistent. Preliminary studies devoid of ESP intervention demonstrated little PM removal, since buildup on the chamber walls distorted the results. The installation of the ESF markedly enhanced the removal efficiency, achieving up to 95.5%. Further analysis revealed that ESP performance depended on PM concentration in the agglomeration chamber, achieving a clearance rate exceeding 98% under optimal conditions. Fine PM (0.35 to 8.7 µm) was more efficiently removed than ultra-fine PM (0.2 to 0.35 µm). The highest removal efficiency was observed at a feed rate of 0.962 mg/s, while the lowest occurred at 0.385 mg/s. A strong positive correlation between particle concentration and removal efficiency (Pearson value up to 0.829) was observed, particularly at feed rates of 0.128, 0.641, and 1.283 mg/s. The study’s findings confirm that the ESP is highly effective in removing particulate matter, particularly fine and ultra-fine particles, with an optimal feed rate, significantly enhancing the system’s performance. Full article