Hydrophilic Filter Research Articles

Flow Dynamics through a High Swelling Nanofiber Membrane Processed at Different Relative Humidities: A Study on a FexOy/Polyvinyl Alcohol Composite.

Addressing the global problem of polluted water requires sustainable, efficient, and scalable remediation solutions, such as electrospun polyvinyl alcohol (PVA) membranes incorporating specific nanoadsorbents. The retention of contaminants depends on membrane swelling, morphology, and the adsorbent within the nanofiber. This study investigated the effect of relative humidity (RH) within the electrospinning chamber on the morphology of the resulting mats and how this affected the flow dynamics depending on whether or not the permeating liquid induced swelling in the membranes. An insolubilized PVA membrane was used as a hydrophilic filter model and a PVA membrane filled with iron oxide nanoparticles (IONPs) as a composite model (PVA + IONPs). The presence of IONPs increases the nanofiber diameter, which decreases when prepared under intermediate RH (IRH). Consequently, the nanofiber configuration, which is critical for filtration tortuosity, is influenced by RH. The initial swelling results in over 60% greater water flux through PVA + IONPs compared to PVA at an equivalent RH. This characterization helps to optimize membrane applications, highlighting that PVA + IONPs exhibit lower permeability values at IRH, indicating improved contaminant retention capabilities.

Enhancing aqueous zinc-ion energy storage performance with ion-mediating carbon quantum dots-modified separators regulating zinc deposition behavior

Aqueous zinc-ion batteries (AZIBs) hold promising applications owing to their safety, cost-effectiveness, and competitive capacity. However, issues such as zinc dendritic formation and side reactions severely impede their practical viability. Utilizing carbon quantum dots (CQDs) to modify cheap, tenacious, and highly hydrophilic filter paper (FP) as separator effectively improves the electrochemical performance of zinc ion energy storage systems. The structured arrangement of CQDs redistributes zinc ion transport and induces uniform zinc icon deposition, thereby improving zinc ion reaction kinetics. Moreover, the rich functional groups on the surface of CQDs readily form hydrogen bonds with active H2O, further inhibiting corrosion reactions. With the assistance of CQDs, the FP-CQDs separator maintains high ionic conductivity and a high zinc-ion transference number, ensuring dendrite-free and corrosion-resistant operation with high coulombic efficiency and a prolonged lifespan of 1200 h at 1 mA cm−2. Zn//AC hybrid capacitors incorporating FP-CQDs separator demonstrate superior capacity retention compared to those using FP separator alone, with a high capacity retention after 600 cycles at 1 A/g, while Zn//V2O5 full batteries also exhibit excellent cycling stability. Given these findings, this study presents a new composite separator for advanced aqueous zinc-ion energy storage systems.

Beyond Traditional Sunscreens: A Review of Liposomal-Based Systems for Photoprotection.

Sunscreen products are essential for shielding the skin from ultraviolet (UV) radiation, a leading cause of skin cancer. While existing products serve this purpose, there is a growing need to enhance their efficacy while minimizing potential systemic absorption of UV filters and associated toxicological risks. Liposomal-based formulations have emerged as a promising approach to address these challenges and develop advanced photoprotective products. These vesicular systems offer versatility in carrying both hydrophilic and lipophilic UV filters, enabling the creation of broad-spectrum sunscreens. Moreover, their composition based on phospholipids, resembling that of the stratum corneum, facilitates adherence to the skin's surface layers, thereby improving photoprotective efficacy. The research discussed in this review underscores the significant advantages of liposomes in photoprotection, including their ability to limit the systemic absorption of UV filters, enhance formulation stability, and augment photoprotective effects. However, despite these benefits, there remains a notable gap between the potential of liposomal systems and their utilization in sunscreen development. Consequently, this review emphasizes the importance of leveraging liposomes and related vesicular systems as innovative tools for crafting novel and more efficient photoprotective formulations.

Density-gradient water-based air filters: Gas/solid-permeable and liquid-impermeable design

A water-based air filter (WAF) composed of an inner cylindrical hydrophilic filter and an outer hollow cylindrical hydrophobic filter was installed in an output chamber filled with water. The WAF with water (WAF-WW) showed outstanding recyclability (average PM2.5 RE = 96.5 %) for up to 100 cycles with consistent long-term performance (ΔREmin and max = 1.4 %) and low pressure drops (ΔP1st and 100th = 3 Pa), which were better than those of commercial HEPA filters (H13) (average PM2.5 RE = 96.2 %, ΔRE = 4 %, and ΔP = 21 Pa), at similar PM2.5 concentrations (1,721 μg/m3) and air velocities (0.92 m/s). The WAF-WW also exhibited excellent recyclability up to the 50th cycle with fast and complete removal (HCHO REat 2-13 min = 100 %) of HCHO gas at very low concentrations (0.08–4.98 ppm). Furthermore, since small PM0.3/PM2.5 particles and total volatile organic compound (TVOC) that are hardly filtered by air filters can be easily and quickly removed by the WAF-WW due to the water filter, this is another extraordinary benefit of the wet process over the dry process.

Combination Screening of a Naïve Antibody Library Using E. coli Display and Single-Step Colony Assay

The use of single-domain camelid antibodies, termed VHHs or nanobodies, has found increasing application in diagnosis, pharmaceutical development, and research because of their superior properties, such as small size, elevated stability, high water solubility, and excellent affinity for the antigen. Antigen-specific VHHs are generated by screening VHH display libraries via bio-panning. However, the bio-panning step needs to be repeated multiple times, which is time-consuming and laborious. Here, we developed a simple and rapid screening method that combined Escherichia coli display and a single-step colony assay to successfully identify positive clones from a naïve VHH library. The library was constructed from peripheral blood mononuclear cells of alpaca, and VHHs were displayed on the surface of E. coli using the inverse autotransporter intimin. Libraries enriched by magnetic cell sorting were screened directly using a single-step colony assay. Colonies formed on the hydrophilic filter and antigen-coated membrane. The expression of VHHs was induced, and those bound to the antigen on the membrane were detected as positive clones. Screening and identification of positive clones required only two days, which saves considerable time and resources compared to existing protocols.

The determination of underivatized chlormequat, fosetyl-aluminium and phosphonic acid residues in maize and soybean by LC-MS/MS.

In this study, a simple, rapid and sensitive method was developed for the simultaneous determination of chlormequat, fosetyl-aluminium and phosphonic acid residues in maize and soybean using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Analytes were extracted with acetic acid solution, purified on an HLB column, and then filtered through a 0.2 μm hydrophilic microporous filter membrane. They were then separated on an IC column using a separation phase consisting of polyvinyl alcohol particles with quaternary ammonium groups. The mobile phase optimised with water was denoted as mobile phase A and that optimised with 200 mmol L-1 ammonium bicarbonate solution containing 0.05% ammonium hydroxide was denoted as mobile phase B. The residues were detected by tandem mass spectrometry with negative electrospray ionization in a multi-reaction monitoring mode. The correlation coefficient (R ≥ 0.997) showed good linear regressions for all analytes in water as well as in maize and soybean matrices with a wide dynamic range of 0.001 to 0.5 mg L-1 for calibration. The mean recoveries (RSDs) of the analytes were in the range 85.0-106.4% (5.5-14.9%), 81.7-109.5% (2.7-11.0%) and 74.7-104.4% (2.9-6.1%) at three concentration levels (0.05, 0.1 and 1 mg kg-1) for the interday test (n = 15). The limit of quantification (LOQ) and detection (LOD) of the method for different matrices were 0.01 and 0.003 mg kg-1, respectively. In conclusion, the established analytical approach has high sensitivity and good accuracy and precision and is suitable for monitoring chlormequat, fosetyl-aluminium and phosphonic acid residues in maize and soybean.

A SiC membrane resistance recovery methodology based on dynamically dust cake layer analysis

Filter cake-induced resistance is a significant contributor to energy consumption in dust filtration processes. This can be optimized by adjusting inlet gas composition, membrane characteristics, and back-flushing parameters. In this study, calcium carbonate (CaCO3) dust with varying hygroscopicity was utilized to investigate the evolution mechanism of the filter cake on SiC membranes under different humidity conditions. The interacting force between particles and between the cake and membrane were analyzed to elucidate the fragmentation mechanism of the cake. It was observed that particles at higher relative humidity (increased RH from 40 % to 85 %) tend to form a more loosely packed cake (hydrophilic filter cake porosity and hydrophobic filter cake porosity increased from 70.8 % to 80.5 % and from 61.4 % to 69 %, respectively) with greater fragility (reduced cohesive force). This characteristic is advantageous for efficient backflushing operations. The strong adhesion between the filter cake and membrane hindered the recovery of the initial filtration resistance. For SiC membrane, the optimized back-flushing parameter is reservoir pressures of 0.2 and 0.15 MPa and pluse-jet intervals of 40 min to hydrophilic and hydrophobic dusts, respectively.

Development of Filtering Electrospray Ionization-Ion Trap Mass Spectrometry Technique for the Rapid Detection of Antibiotic Residues in Food

This article reports on the development of an atmospheric pressure filtering electrospray ionization (FESI) source – composed of a syringe, a filter, and the ESI source – for the determination of furazolidone, amoxicillin, nitrofurantoin, and nitrofural, common antibiotics. Spiked food samples were also analyzed; the analytes were placed in the filter head, and the flow rate of the extraction solution from the syringe pump was adjusted. Using a mixture of oleic acid and antibiotics, hydrophilic and hydrophobic filters were compared, demonstrating the advantage of FESI in reducing the background and noise for the mixture. The device simplifies not only the experimental procedure but also the sample pretreatment process. Additionally, the limits of detection of the antibiotics were determined to be 1 mg L−1 for furazolidone, amoxicillin, and nitrofurantoin and 2 mg L−1 for nitrofural. The linear regression coefficients (R 2) of the antibiotic standard solutions were all ≥0.99. Furthermore, the spiked recovery rates of pork, chicken, and egg samples ranged from 73.3% to 107.5%, with relative standard deviations (RSDs) from 1.1% to 15.6%. This study uncovers the potential capabilities of ion trap mass spectrometry (ITMS) for the on-site detection of antibiotics and offers a new method for ensuring food safety.

Multidisciplinary Approach to Deciphering Etoposide Infusion Reactions and Potential Role of Polyethersulfone Filter Membranes.

Etoposide, a topoisomerase II inhibitor used clinically to treat cancer, has been associated with severe anaphylactic infusion related adverse drug reactions (ADRs). In a previous study we identified a hydrophilic polyethersulfone filter as a possible cause of increased rates of pediatric etoposide infusion reactions. In this multidisciplinary follow-up analytical study, we aimed to assess the chemical structure of etoposide after passing through the same hydrophilic polyethersulfone filter. An etoposide 0.4 mg/mL infusion was prepared under aseptic conditions and then passed through a standard IV infusion set with an in-line filter in place. Samples were taken in triplicate using a needle-less access system to include sampling sites directly from the IV bag port and from the IV tubing both before and after the in-line filter. Samples were diluted into mobile phase, then an aliquot was injected into a high-performance liquid chromatography mass spectrometry HPLC-MS (Thermo TSQ Quantum Ultra) system coupled to a Diode Array Detector (DAD) (Thermo Dionex Ultimate 3000). Etoposide was monitored using a selected reaction monitoring scan (SRM) of 606.2/228.8 and wavelengths of 210, 220, 254, and 280 nm for 30 minutes. No detectable differences were observed upon comparing the three samples. Based on these results, a chemical change in etoposide resulting from an in-line filter is unlikely to be the primary cause of increased rates of infusion reactions. Pharmacists working in healthcare systems, observe many ADRs, but rarely have the resources necessary to investigate the potential etiology or causality. This report highlights importance of multi-disciplinary collaboration to investigate serious ADRs.

Construction of filterable and intelligent flexible NiB-Based catalytic electrode toward efficient overall seawater splitting

It is significance to develop non-precious metal catalytic electrodes that can be used for electrolysis of seawater to produce hydrogen to alleviate the energy crisis and environmental pollution. In this work, a stable, efficient and filterable flexible self-supporting electrode is prepared by in-situ growth of nickel and boron on porous hydrophilic filter paper (HP) via mild electroless plating at 298 K (Ni-B@HP). Due to NiB in-situ growth on the surface of the fiber, which has fast electron transfer ability and high intrinsic activity. In the electrolytic water hydrogen and oxygen evolution reaction process (HER and OER), the overpotentials are only 32 mV and 300 mV to achieve a current density of 10 mA cm−2, and there is no attenuation after stable operation for>3 days at industrial current density (>500 mA cm−2). More attractively, with filterable paper as the substrate, the Ni-B@HP electrode maintains its own filterability to realize seawater and sewage self-filtration, and has flexible characteristics of bending, folding and variant. This strategy of constructing electrodes can be applied to various extreme conditions and provides a new strategy for current sewage treatment and seawater hydrogen production.

CDs Regulated Sulfur-Based Flexible Electrode with Range pH Values for Efficient and Durable Hydrogen Evolution Reaction.

How to mildly structure a high intrinsic activity and stable catalytic electrode to realize long-term catalytic water splitting to produce hydrogen at a wide range of pH values at industrial high current is a challenge. Herein, this work creatively proposes to prepare industrial-grade catalytic electrodes with high efficiency and stability at high current density through carbon quantum dots (CDs) modification nickel sulfide on hydrophilic flexible filter paper via one-step mild chemical plating (denoted as CDs-Ni3 S2 @HFP). The intrinsic activity and surface area, electron transfer ability, and corrosion resistance of Ni3 S2 material are increased due to the regulation, homogenous, and high concentration doping of CDs. The overpotential of the flexible catalytic electrode is only 30, 35, and 87mV in 1m KOH, simulated seawater (1m KOH + 0.5m NaCl), and neutral electrolyte (0.5m PBS) at a current density of 10mA cm-2 . More attractively, the CDs-Ni3 S2 @HFP electrode achieves over 500h of efficient and stable catalysis at industrial high current density (500mA cm-2 ). Due to the advantages of mild, universal, and large-area preparation of catalytic materials, this work provides technical support for flexible catalytic electrodes in efficient catalysis toward water splitting, energy storage, and device preparation.

Green carbon induced super hydrophilic bioFoam filters for hazardous emerging pollutants removal and their sustainable value addition

Solvothermal derived carbon (STC) offers unique characteristics due to their confined morphology, chemical functionality, surface acidity as well as high surface area. On the other hand, highly porous biofoam can be prepared using natural polymers with varying porosity and surface characteristics. Herein, we have prepared multi-functional STC induced biofoam (STC-BF) as a module-based device for water treatment applications. The biofoam was converted into highly porous architecture through lyophilisation of composite gel composed of Agar-Agar (Ar) and Chitosan (CS). The obtained STC-BF were studied for their stability, physical and chemical compositions using different analytical techniques such as ATR-IR, XPS, TGA, FE-SEM, Zeta potential. Furthermore, the stable characterized STC-BFs were tested as an adsorptive filter for removal of emerging pollutants like organic dyes involving methyl orange (MO), anions such as Chromate (CrO42−) and Fluoride (F−), and other emerging pollutants like Ciprofloxacin (CIP), Paracetamol (PAR), Dichlophenac (DIC), respectively. Detailed studies on STC, C-BF and STC-BF showed that the synergetic effect of both STC and bio-foam in the form of STC-BF exhibited an exceptionally high maximum adsorption capacity of 896.56 mg/g of MO, 387.56 mg/g for CIP, 142.89 mg/g for CrO42− ion and 31.45 mg/g for F− ion. Further, foam filters were tested for its real time and technological feasibility in which the universal foam filter showed a cumulative flux of ~400 L−1m−2h−1 with >90% rejection for MO, CIP and CrO42− ions and around 60% rejection for F− ions.

Comparison of the Anode Side Catalyst Supports with and without Incorporation of Liquid Electrolyte Layer on the Performance of a Passive Direct Methanol Fuel Cell

In the passive direct methanol fuel cell (DMFC) operation, the catalyst plays an important role in electrical energy production. Efficient catalyst support increases the power output and simultaneously decreases irreversible losses in the fuel cell (FC). Effective utilization of methanol at the anode end reduces methanol crossover by selecting good anode catalyst supports. In the present study, two types of anode catalyst support of carbon and carbon black are used. The two types of anode catalysts are Pt-Ru/C+ Pt-Ru/black and Pt-Ru/C along with a 2 mm thick liquid electrolyte (LE) layer placed in the middle of the two half MEAs. The LE layer is made of piled hydrophilic filter papers, which are soaked in a solution of 1 M H2SO4 concentration. The methanol concentration is varied from 1 M to 12 M and from 1 M to 5 M with and without LE-inserted FC, respectively. The passive DMFC with Pt-Ru/C+ Pt-Ru/black anode catalyst and the LE layer exhibit the best performance, producing an MPD of 5.328 mWcm-2 at a 5 M methanol concentration. The MPD produced by the anode catalyst of Pt-Ru/C+ Pt-Ru/black and Pt-Ru/C along with the 2 mm thickness LE layer incorporated fuel cell is 75.26% higher than conventional-based FC of anode catalyst of single-layer catalyst of Pt-Ru/C.

Evaluation of Physiochemical and Microbiological Stability of 2-[18F] Fluoro-2-Deoxy-D-Glucose, [18F]FDG: Synthesized in the Cyclotron Facility of National Institute of Nuclear Medicine and Allied Sciences

2-[18F]Fluoro-2-Deoxy-D-Glucose ([18F]FDG) is very effective and the most successful radiotracer for the assessment of glucose metabolism in the brain, heart, and lungs. It has also been used for imaging different tumors in oncology. The purpose of this study was to evaluate the stability and quality of [18F]FDG synthesized by the newly installed 18MeV Cyclotron facility at the National Institute of Nuclear Medicine and Allied Sciences (NINMAS). [18F]FDG was synthesized by nucleophilic fluorination of Mannose-triflate followed by basic hydrolysis with an IBA Synthera® auto synthesizer. [18F]FDG solution was collected in a sterilized vial after the filtration by a vented Millex®-GS 0.22µm syringe-driven hydrophilic filter. An aliquot of [18F]FDG solution was taken 0, 2, 4, 6, and 8 hours after the synthesis. All quality control parameters were measured in the first evaluated period, immediately (i.e., 0 hours) after synthesis. Radiochemical purity (RCP) was measured for all [18F]FDG samples and for all time points. The radiochemical and radionuclidic purity was more than 95% and 99.99% respectively. The [18F]FDG was physiochemically & microbiologically stable over 8 hours. Bangladesh J. Nuclear Med. 26(1): 44-50, 2023

Dyeable Hydrophilic Surface Modification for PTFE Substrates by Surface Fluorination.

Polytetrafluoroethylene (PTFE) is the most widely used fluoropolymer that has various functionalities such as heat resistance, chemical resistance, abrasion resistance, and non-adhesiveness. However, PTFE is difficult to dye because of its high water repellency. In this study, the PTFE surface was modified by a combination of gold sputtering and surface fluorination to improve dyeability. X-ray photoelectron spectroscopy indicated that, compared with the untreated sample, the gold-sputtered and acid-washed surface of PTFE had a negligible number of C-F terminals. Furthermore, the intensity of the C-C peak increased drastically. The polar groups (C=O and C-Fx) increased after surface fluorination, which enhanced the electronegativity of the surface according to the zeta potential results. Dyeing tests with methylene blue basic dye showed that the dye staining intensity on the surface of fluorinated PTFE samples was superior to other samples. It is due to the increased surface roughness and the negatively charged surface of fluorinated PTFE samples. The modified PTFE substrates may find broad applicability for dyeing, hydrophilic membrane filters, and other adsorption needs.

An introduction to Geosynthetic Cementitious Composite Mats and Barriers – a new approach to lining canals

A new class of geosynthetic has recently emerged known as GCCMs (Geosynthetic Cementitious Composite Mats) defined by the ASTM D-35 committee in 2017 as ‘a factoryassembled geosynthetic composite consisting of a cementitious layer contained within a layer or layers of geosynthetic materials that becomes hardened’. GCCMs consist of a three-dimensional fibre structure filled with a dry cement/concrete mix, overlain by a hydrophilic filter layer and underlain by a watertight membrane, which is typically a polymeric film. The material is delivered in its dry format and unrolled into place using similar installation techniques to traditional geosynthetics. Once in place, it is hydrated by spraying with water and the cement/concrete mix hardens. The result is a watertight polymeric film which is overlain by a protective fibre-reinforced concrete layer. GCCMs have been in use since 2009 and are predominantly used for the lining of water channels for small scale drainage. More recently a variant of GCCMs has emerged which integrates a geomembrane liner onto the rear surface which allows the joints to be thermally welded. These are known as Geosynthetic Cementitious Composite Barriers (GCCBs). It is estimated that Egypt has more than 110,000 kilometers of canals comprised of approximately 30,000 km of public canals (first and second level) and 80,000 km of private third-level canals (mesqas) and irrigation ditches. A common problem associated with canals, is seepage. Seepage can result directly in water loss through the network or result in waterlogging of adjacent land. In the case of land used for cultivation, waterlogging can reduce crop yields or cause salinization of the soils. This does not only occur in earthen canals, but also in concrete lined canals, particularly those that have experienced cracking, scour, panel separation or damage. It is also a common misconception that concrete lining of canals is an effective method of mitigating seepage losses. The 25-year study performed by the USBR indicates that concrete over geomembrane has a 95% effectiveness at reducing seepage through canals1. This abstract introduces a revolutionary new class of materials called Geosynthetic Cementitious Composite Mats (GCCM’s), specifically Type II GCCM’s to ASTM D8364 for lining of bulk water transportation canals. The Type II GCCM in question consists of concrete encapsulated by between two geotextile layers with a minimum 1mm thick LLDPE geomembrane backing which can be thermally welded to produce a testable and low permeability joint, per ASTM D5820, with air channel testing to ensure a leak free installation. Because it is a composite of concrete and geomembrane in a single application, installation can occur as a one-stepprocess imparting both cost and time savings to the project. The abrasion resistance of the concrete layer is 3.5 times that of typical 20Mpa concrete typically used for canal applications. With a design life of more than 50 years, this new product classification will provide a feasible, long-term solution to help preserve and protect fresh, clean water, one of Egypt’s most precious – and ever more scarce – natural resources.

Determination of 107 typical pesticides and metabolites in raw water and drinking water by online-solid phase extraction coupled with ultra performance liquid chromatography-triple quadrupole mass spectrometry

In order to monitor the risk of pesticide pollutants in drinking water, an analytical method based on online-solid phase extraction coupled with ultra performance liquid chromatography-triple quadrupole mass spectrometry (online-SPE-UPLC-MS/MS) was established for the simultaneous rapid screening and determination of 107 pesticides and metabolites (organophosphorus, organic nitrogen, organic heterocycle, carbamate, amide, benzoyl urea, neonicotinoid, etc.) in raw water and drinking water. Different injection volumes (5, 10, and 15 mL) were compared. The detection response increased with an increase in the injection volume, but the matrix effect also became more pronounced. Under the premise of ensuring the sensitivity of the method and meeting the detection requirements, the injection volume was selected as 5 mL. Accordingly, the samples were filtered through a 0.22-μm hydrophilic polytetrafluoroethylene filter, and then, 5 mL samples were injected into the online-SPE system by the automatic sampler. After adsorption on an X Bridge C18 online-SPE column, the samples were washed with pure water and eluted by gradient elution using acetonitrile and 0.1% formic acid aqueous solution as the mobile phases, with separation on an ACQUITY HSS T3 column. The samples were detected by multiple reaction monitoring with electrospray ionization in positive and negative ion modes, and quantified by an external standard method. Using raw water and drinking water as the sample matrices, the accuracy and precision of the method were verified. The 107 pesticides and metabolites showed good linear relationships in different ranges with correlation coefficients (r2)>0.995. The limits of detection (LODs, S/N=3) of the method were 0.03-1.5 ng/L, and the limits of quantification (LOQs, S/N=10) were 0.1-5.0 ng/L. The target pesticides were spiked at concentration levels of 1, 20, and 50 ng/L. The spiked recoveries of the 107 targets in raw water and drinking water samples were 60.6%-119.8% and 61.2%-119.0%, respectively. The corresponding relative standard deviations (RSDs, n=6) were 0.3%-18.6% and 0.4%-17.1%. The pesticide residues in raw water and drinking water were determined by this method. Amide herbicides, triazine herbicides, triazole insecticides, carbamate insecticides, and neonicotinoid insecticides had high detection rates. The detected concentrations ranged from 0.1 to 97.1 ng/L in raw water and from 0.1 to 93.6 ng/L in drinking water. The sample consumption of online-SPE method was lower than that in the traditional off-line SPE methods, which greatly improved the convenience of sample collection, storage, and transportation. The samples only need to be filtered before injection and analysis. The method is simple to operate and shows good reproducibility. With this online-SPE method, only 23 min were required from online enrichment to detection completion. The developed method has the advantages of high analytical speed and high sensitivity. The method is suitable for the trace analysis and determination of 107 typical pesticides in raw water and drinking water, which effectively improves the detection efficiency of pesticides in water and has high potential for practical application. It can extend technical support for the pollution-level analysis of typical pesticides and metabolites in drinking water and provide an objective basis for human health risk assessment.

Penetration of Water-Soluble Material through Gas-Cleaning Filters.

To predict the behavior of gas-cleaning filters during real-world operation, it is essential to understand their response to ambient conditions. The temporary presence of water droplets in gas-cleaning filtration systems due to fog, spray rain, or condensation, as examples of irregular events, has an impact on the filters’ operating performance, especially when soluble particles are present. In this work, surface filters were loaded with mixtures of water-soluble salt particles and insoluble glass spheres. These were, subsequently, exposed to water mist and dried by a particle-free gas stream. A novel approach to analyze the drainage of solution on filters with soluble filter cakes is presented, which allows the detection of solubles on the clean gas side of the filter. As a result, this work, for the first time, presents a sighting of the penetration of soluble filter cake material through gas-cleaning filters. Furthermore, filter performance, in terms of differential pressure and fractional separation efficiency, was determined and a characteristic differential pressure evolution for hydrophilic filters during exposure to water mist was also identified. The fractional separation efficiency of gas-cleaning filters decreases due to exposure to water mist. The findings are supported by scanning electron microscopy (SEM) images, energy-dispersive X-ray (EDX), and X-ray microtomography (µ-CT analysis) images.

Four-Dimensional Visualization of Microscale Dynamics of Membrane Oil Fouling via Synchrotron Radiation Microcomputed Tomography.

Although oil-water separation technology via wettability-controlled membranes has emerged as a promising technology to treat oily wastewater, membrane fouling by faulents such as sludge flocs and colloids, and the consequent clogging of pores, severely degrades the efficiency of filtration systems. One of the main promotors of fouling by faulents is oil fouling, which is also a form of fouling itself. Despite considerable practical and academic interest in the analysis of oil-fouled membranes, direct visualization of the entire process of oil infiltration into hydrophilic membranes is still preliminary owing to (i) the similar optical contrast and physical density between oil and water, (ii) the low penetration depth of imaging methods, and (iii) the lack of 3D segmentation capability. In this study, microcomputed X-ray tomography using tunable synchrotron radiation provided direct high-speed 3D visualization of the microscale dynamics of the oil infiltration of a prewetted hydrophilic filter membrane over time. Direct visualization of the interfacial dynamics of oil infiltration opens a window into the complex liquid (water/oil)-gas-solid interface and thus helps furnish an in-depth understanding of oil fouling in the prewetted membrane.

Carboxylated cellulose nanocrystals as environmental-friendly and multi-functional additives for bentonite water-based drilling fluids under high-temperature conditions

During the oil and gas drilling engineering, the selection of drilling fluids must take account of the technical and environmental factors. This study investigated the effectiveness of carboxylated cellulose nanocrystals (denoted as CNCs) as environmentally friendly additives for improving the rheological, filtration, and inhibitive properties of water-based drilling fluids (WBDFs). CNCs used in this study were modified by carboxylation reaction, displaying small size, negative surface charge, good colloidal stability, and prominent shear-thinning behavior. Experimental results indicated that BT/CNC suspensions had superior rheological properties, low fluid loss volumes, and effective inhibition, even at 140 °C. Microstructure analysis demonstrated that CNCs could attach to the surface of BT via hydrogen bond and ionic bond. CNCs, BT, and vicinal water molecules could form a stiff gel network, which had a strong resistance to flow under shear force, leading to a significant improvement in the rheological properties. Moreover, under the differential pressure, BT/CNC suspensions formed thin and less hydrophilic filter cakes with compact layered structure, thereby efficiently decreasing the fluid loss volume. Finally, due to the gel network and filtration ability, BT/CNC suspensions performed low water activity, which was beneficial for preventing the penetration of free water into the shales and borehole well. Thus, CNCs also exerted satisfactory inhibition on hydration and dispersion of BT and shales. As a result, CNCs showed great potential to be used as efficient, multi-functional, and environmentally friendly additives in WBDFs.