Breakthrough Volume Research Articles

An amide-based covalent organic framework chemically anchored on silica nanoparticles for headspace microextraction sampling of halogenated hydrocarbons in air

A needle trap device (NTD) was developed using an amide-based covalent-organic framework (COF), chemically bonded to silica nanoparticles. The NTD was coupled with gas chromatography-flame ionization detection (GC-FID) and employed for the headspace microextraction analysis of halogenated hydrocarbons (HHCs) in the air. The adsorbent was characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FE-SEM) techniques.Optimal values for the experimental variables were assessed using response surface methodology (RSM) with a central composite design (CCD), thereby reducing the number of experiments, material consumption, costs, and time. The optimal values for desorption time and temperature were obtained 5 min and 260 °C, respectively. Breakthrough volume (BtV) was studied over the range of 0.5 - 3 times the occupational exposure limit (OEL) and its optimal value was found to be 1200 mL. The optimal sampling temperature and relative humidity (RH) were obtained 20 °C, and 15 %, respectively. The limits of detection (LODs) and limits of quantification (LOQs) were ranged from 0.013 to 0.077 μg l-1 and 0.041 to 0.21 μg l-1, respectively, with a linear dynamic range (LDR) of 0.04 to 100 μg l-1. The method's repeatability and reproducibility (RSD %) were observed over the ranges of 5.3 - 6.4 % and 4.7 -6.9 %, respectively. A statistically validated agreement was observed between the NTD-GC-FID method and the NIOSH 1003 standard procedure for the sampling and determination of HHCs in real workplace air samples, demonstrating the reliability and accuracy of the developed approach.

Add-On Device Powered by Parallelized Adsorption Traps for Preconcentrator-GC-MS Measurement of sub-pmol/mol Levels of NF3.

In this study, an add-on preconcentration device powered by parallelized pretraps (PPTs) was utilized to measure the sub-pmol/mol levels of NF3 in N2. The add-on preconcentrator was coupled to the detachable trap preconcentrator (DTP) with a gas chromatograph-mass spectrometer [Anal. Chem. 2019, 91, 3342-3349]. The breakthrough volume of the parallel configuration was found to be substantially higher than that of the serial configuration with the same amount of adsorbent (HayeSep D). Liquid oxygen (LO2) cooling (-183 °C) exhibited better preconcentration performance for NF3 in N2 compared to NF3 in air (N2 + O2) with liquid nitrogen cooling (-195 °C) and NF3 in air with LO2 cooling. The DTP unit was essential to discriminate residual species, such as N2, O2, CO2, and CF4, of which the preconcentrated portion in the PPT can be excessive, enabling the overwhelm filtering capability of the quadrupole mass spectrometer. The limit of detection of NF3 in N2 of the PPT/DTP/gas chromatograph-mass spectrometer was 0.01 ppt, which is significantly better than that determined without using the add-on preconcentration device (0.21 ppt).

Numerical simulation of wormhole propagation in fractured carbonate rocks during acidizing using a simplified Stokes–Brinkman model

Most numerical simulations for modeling acid reactive fluid transport and wormhole propagation during matrix acidizing, waterflooding, and CO2 sequestration in carbonate formations are computationally expensive, limiting real-time reservoir management and deep learning training datasets generation for inverse modeling research. Therefore, there is a need for less computationally expensive acid-reactive fluid flow models with adequate accuracy. This study developed and validated a simplified acid reactive-transport model by integrating a simplified Stokes–Brinkman model (as opposed to Darcy’s law), an averaged continuum model, and a pseudo-fracture model. Using FEniCS, the model effectively simulates acid-reactive fluid transport and wormhole propagation in carbonate rocks, achieving a high R-square value of about 0.97 based on a quantitative comparison of the breakthrough volume with other models. The simplified model can also simulate wormhole propagation for the reciprocal of the Damköhler number (1/Da) ranging from 0.001 to 1 with adequate accuracy. Sensitivity studies on the natural fracture parameters such as orientation, length, width, and density showed that higher fracture density, wider fracture aperture, longer fracture length, and orientation aligned with the direction of acid injection contribute to lower pore volume to breakthrough ratio but may not increase long-term acid stimulation efficiency. Also, the presence or absence of fractures in the matrix does not alter the dissolving patterns and optimum injection rate. This simple acid reactive-transport model can generate large training datasets for developing surrogate models in deep learning research. Finally, the FEniCS code in this paper is shared so future researchers can reproduce the results or extend the research work.

Effects of adding zeolite particles on the hierarchical microstructure of zeolite-geopolymer composites and their Sr2+ adsorption properties

Strontium ions can be removed from wastewater in fixed-bed reactors by adsorption on hierarchical materials (different pore sizes and phases). A detailed understanding of the materials multiscale structure is therefore crucial to optimize their sorption properties. This article presents a multi-technique approach developed to characterize the relationship between microstructure and adsorption in a range of Linde-type A (LTA) zeolite-geopolymer composites,. Two-dimensional scanning electron microscopy and 3D X-ray tomography were used to image the porous and solid phases at different length scales. Advanced numerical methods involving machine learning were applied to segment the images and provide quantitative morphological values describing the porous network geometry and the location and accessibility of the zeolite particles in the geopolymer. These results were then correlated with the materials sorption properties, measured in batch and column processes. Increasing the materials zeolite content (from 0 to 27 wt%) slowed down their adsorption kinetics but increased their maximal adsorption capacities from 20 to 49 mg.g−1 and Sr2+-selectivity at equilibrium. In breakthrough experiments, the material with highest zeolite content had a much higher breakthrough volume passing from 169 to 478 ml in the presented experimental conditions (much higher wastewater decontamination capacity), but a shallower breakthrough curve (lower column efficiency).

Remarkable enhancement in radio-cesium uptake from acidic feeds into an extraction chromatography resin containing a calix[4]arene-mono-crown-6 ligand

An extraction chromatography resin, prepared by the impregnation of bis-octyloxy-calix[4]arene-mono-crown-6 (BOCMC)onto an acrylic ester based polymeric support material, gave excellent uptake data for the removal of radio-cesium (Cs-137) from nitric acid feed solutions. The weight distribution coefficient (Kd) value of >300 obtained during the present study at 3 M HNO3 was the highest reported so far while using a calix-crown-6 based extraction chromatographic resin material. Analogous resin reported previously has yielded a Kd value <100 at comparable feed conditions. The sorbed metal ions could be efficiently desorbed with de-ionized water. Kinetic modeling of the uptake data indicated that both the film and the intra-particle diffusion mechanism are simultaneously operating in the sorption of Cs+ion onto the BOCMC resin. The metal ion sorption data were fitted to the sorption isotherm models and did not conform to the chemisorptions of physisorption models and indicated a pi-pi interaction between the benzene rings of the calix-crown-6 ligand and the Cs+ ion. The reusability of the resins was quite satisfactory after 5 cycles and the radiation stability of the resin material was very good upto an absorbed dose of 500 kGy. The results of column studies were quite encouraging with 15 mL (9 bed volumes) as the breakthrough volume while the elution was complete in about 12 bed volumes of de-ionized water.

Functionalized ionic liquids as an efficient sorbent for solid-phase extraction of tetracyclines in bovine milk

In this research, a novel ionic liquid-based sorbent, N,N,N-trimethyl-3-(triethoxysilyl)propan-1-aminium bromide silica gel (SiO2-NH2), was successfully synthesized through chemical interaction. The synthesized adsorbent was first applied as a stationary phase for the preconcentration of tetracycline antibiotics (TCAs) at trace level from milk samples via solid-phase extraction. The structure of SiO2-NH2 was studied by Fourier-transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Energy-Dispersive X-ray Spectroscopy (EDX), and Scanning Electron Microscopy (SEM) to verify the successful synthesis based on the existence of ionic liquid on the surface of silica gel. The factors impacting a solid-phase extraction procedure were investigated, such as types of material, sample volume, breakthrough volume, and elution conditions. In addition, we also compared self-synthetic SPE cartridges with commercial cartridges with the assistance of LC-MS/MS. The SiO2-NH2 effectively retained and separated all three tetracycline antibiotics, including tetracycline (TC), oxytetracycline (OT), and chlortetracycline (CT), with a recovery efficiency of 99.4 % to 100 %. The maximum recovery was obtained when the analytes were eluted using a suitable mixture of acetonitrile, methanol, and acetic acid (2:2:1, v/v/v) for a volume of 1 mL. The enrichment factors of TC, OT, and CT were 110 mL, 150 mL, and 100 mL, respectively. The detection limits for TC, OT, and CT were 0.360, 0.279, and 0.390 mgL−1, corresponding with lower than 5 % relative standard deviation (RSD).

A fast thermal desorption unit for micro thermal desorption tubes, Part I: Development of the system and proof of concept measurements with hyper-fast gas chromatography

A system consisting of a thermal desorption unit (TDU) and micro thermal desorption tubes (μTD-tubes, 1.4 mm I.D., 10mg Tenax TA) for fast desorption of analytes was developed for the efficient combination of hyper fast gas chromatography with thermal desorption. The fast desorption is achieved by a significantly reduced thermal mass compared to conventional thermal desorption tubes. Therefore, extremely fast heating and cooling cycles are possible. Proof of concept measurements combining the new setup with a flow-field thermal gradient gas chromatograph (FF-TG-GC) and FID detection show good precision and linearity with R2≥0.995 in the analysis of an n-alkane mix (C8-C20). Thermal desorption occurs within 12s. The impact of reduced μTD-tube dimensions on desorption time, full width at half maximum (FWHM), breakthrough volumes, tube flow rates ergo linear velocities, porosity and back pressure is discussed.

Mesoporous Mg–Al–Ti composite oxide incorporated mixed matrix ultrafiltration membrane with superior multi-heavy metal removal capacity, anti-fouling & anti-microbial property

Mesoporous Mg–Al–Ti ternary composite oxide nano-adsorbents have demonstrated an exceptional performance to remove multiple heavy metals (As, Pb, Cd, Cr). Incorporation of these nanoparticles (NPs) in polysulfone membrane created a multifunctional mixed matrix membrane (MMM) with heavy metal adsorption capacity (both cationic and anionic species), enhanced hydrophilicity, anti-fouling property, and anti-microbial activity. The best heavy metal removal performance was shown by the membrane incorporated with 0.8 wt% NPs. Hydrophilicity improvement was studied through the decrease in water contact angle from 71° to 57° and surface probing using atomic force microscopy (AFM). With a maximum As(III) adsorption capacity of 256.6 mg/g, the membrane had a breakthrough volume of 25L and could provide safe drinking water for 19 h from a real Arsenic (As) contaminated groundwater sample with a flux of 48 l/m2-h. Beyond that, >90 % removal of Cd, Pb & Cr was also observed with maximum adsorption capacity of 652.9 mg/g, 332.5 mg/g, and 89.4 mg/g respectively. 92.5 % flux recovery after filtering a 1000 ppm bovine serum albumin showed the anti-fouling property. Successful inhibition of both gram-positive and gram-negative bacterial growth, and >99.99 % removal of colony forming units (CFU/ml) in the filtration process confirmed the anti-microbial resistance. With its multifunctionality, these membranes hold great potential for practical water treatment applications.

Impact of rock heterogeneity on reactive flow during acid stimulation process

Acid stimulation within carbonate rocks represents a crucial aspect of reactive flow applications in subsurface porous media and has been widely used in carbonate reservoir development attributed to its rapid effectiveness and cost-efficiency. This study is motivated to investigate further the impact of rock heterogeneity on the acid stimulation process. The two-scale continuum model is employed for capturing mass, momentum, and energy transfer during the acid stimulation process. The core-scale model is expanded to consider the specific composition of solid minerals, including reactive minerals such as calcite and dolomite and non-reactive ones like quartz and clay. A heterogeneity generator is developed by coupling with the open-source geostatistical program to produce different heterogeneous parameters using random seeds with varying spatial correlation lengths. Sensitive cases are performed to present an investigation into the influence of mineral composition and matrix heterogeneity on the acid stimulation process. Results show that the typical results of acid stimulation are closely tied to different heterogeneity conditions. The optimum conditions for acid stimulation are sensitive to the concentration of reactive components. The optimum acid injection rate declines as dolomite content increases, while the corresponding acidizing breakthrough volume reduces with higher calcite levels. The presence of mineral layers, especially in horizontal distributions, complicates acid fluid efficiency due to the competitive reaction between calcite and dolomite. Compared to the heterogeneous distribution of minerals, matrix heterogeneity plays a critical role in acid fluid consumption efficiency. Increasing heterogeneity leads to significant reductions in breakthrough volumes, largely governed by the correlation length.

The effects of metal-oxide content in MnO2-activated carbon composites on reactive adsorption and catalytic oxidation of formaldehyde and toluene in air

The deterioration in air quality caused by volatile organic compounds (VOCs) has become an important environmental issue. Here, activated carbon (AC) composites with manganese oxide (MnO2: 1 % to 50 %) are synthesized as MAC for the removal of formaldehyde (FA) and toluene in air through a combination of reactive adsorption and catalytic oxidation (RACO) at room temperature (RT). The best-performing composite (MAC-20: 20 % of MnO2) exhibits a 10 % breakthrough volume (BTV10%) of FA and toluene at 41.2 and 377 L g−1, respectively while realizing complete oxidation of FA and toluene into carbon dioxide (CO2) at 100 °C and 275 °C, respectively. The reaction kinetic rates (r) for 10 % removal efficiency of FA and toluene (XFA or T) at RT are estimated as 9.82E-02 and 3.20E-02 mmol g−1 h−1, respectively. The high performance of MAC-20 can be attributed to its enriched adsorption capacity of oxygen vacancy (OV) and the presence of adsorbed oxygen (OA), as shown by an Mn3+/Mn4+ ratio of 0.729 and an OA/lattice‑oxygen (OL) ratio of 1.50. The results of this study highlight the interactive roles of oxygen abundance and temperature in the generation of distinctive oxidation patterns for FA in reference to toluene. This study is expected to offer practical guidance for the implementation of RACO against diverse VOCs for efficient management of air quality.

An Investigation of Gas-Fingering Behavior during CO2 Flooding in Acid Stimulation Formations

Summary CO2 flooding is emerging as a pivotal technique used extensively for carbon capture, utilization, and storage (CCUS) strategies. Acid stimulation is one common technique widely used to improve well-formation connectivity by creating wormholes. This work is motivated to investigate the gas-fingering behavior induced by acid stimulation during CO2 flooding. We present an integrated simulation framework to couple the acid stimulation and CO2 flooding processes, in which the two-scale continuum model is used to model the development of wormhole dissolution patterns. Then, sensitivity case simulations are conducted through the equation of state (EOS)–based compositional model to further analyze the CO2 fingering behavior in acid stimulation formations separately under immiscible and miscible conditions. Results demonstrate that for acid stimulation, the typical dissolution patterns and the optimal acid injection rate corresponding to the minimum acid breakthrough volume observed in the laboratory are prevalent in field-scale simulations. For CO2 flooding simulation, the dissolution patterns trigger CO2 fingering (bypassing due to the high conductivity of wormholes) in the stimulated region, and a lateral boundary effect eliminating fingers exerts its influence over the system through transverse mixing. The optimal acid injection rate varies when the focus of interest changes from the minimum acid breakthrough volume to CO2 flooding performance. The best CO2 flooding performance is always observed in uniform dissolution, and the dissolution patterns have a greater influence on the performance under miscible conditions. This work provides technical and theoretical support for the practical application of acid stimulation and CO2 flooding.

Needle trap devices packed with an imine-based 2D COF: An innovative tool for the sampling of polycyclic aromatic hydrocarbons in air

This study introduces a new method for sampling and microextraction of polycyclic aromatic hydrocarbons (PAHs) in the air using needle trap devices (NTDs) packed with an imine-based covalent-organic framework (COF) as an adsorbent. The NTD was coupled with gas chromatography-flame ionization detection (GC-FID) for analytes’ separation and quantification. The COF adsorbent was synthesized using a solvothermal method at room temperature and packed inside a stainless-steel needle. The adsorbent was characterized using X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM-EDS) and Brunauer-Emmett-Teller (BET) analysis. The method was developed in the laboratory under various conditions and subsequently applied in the field to compare the results with those obtained using sampling and analytical method-NIOSH 5528. The desorption conditions and breakthrough volume (BtV) were optimized at recommended exposure limits concentration using response surface methodology (RSM) with a central composite design (CCD). Accordingly, the optimal values for desorption temperature and BtV were obtained 310 °C and 2840 mL, respectively. The limits of detection (LODs) and the limits of quantification (LOQs) were found to be 0.021–0.027 and 0.065–0.091 μg L−1, respectively. The repeatability and reproducibility of the method (R%) were estimated to be 4.02–6.83 % and 8.51–10.34 %, respectively. Also comparing the mean concentrations of the samples collected by the NTD and the NIOSH 5528 method, revealed no statistically significant differences between the methods (p > 0.05). Overall, the COF-packed NTD was identified as an appropriate and reliable method for sampling and extracting occupational and ambient contaminants in the workplace air.

Measurements of atmospheric C10–C15 biogenic volatile organic compounds (BVOCs) with sorbent tubes

Abstract. Biogenic volatile organic compounds (BVOCs; e.g. terpenes) are highly reactive compounds typically present at sub-parts-per-billion mole fractions in the air. Due to this, their measurements are challenging and they may suffer losses during sampling, storage and analyses. Even though online measurements of BVOCs are becoming more common, the use of sorbent tubes is expected to continue because they offer greater spatial coverage compared to online measurements, and no infrastructure (e.g. electricity, housing/shelter with stable temperature and humidity, sampling lines) is required for sampling. In this study, the performance of an offline technique for the measurement of BVOCs based on sorbent tube sampling was evaluated. Tested compounds included eight monoterpenes, five sesquiterpenes and five oxygenated BVOCs, which are generally either directly emitted (1,8-cineol, linalool, bornyl acetate) or oxidation products (nopinone and 4-acetyl-1-methylcyclohexene). Two sorbent materials (Tenax TA and Carbopack B) and four tube materials (stainless steel (SS), SilcoNert 1000, glass and glass-coated SS) were used. The laboratory evaluations determined the storage stability, breakthrough volumes, suitable tube materials, recovery from ozone scrubbers and particulate filters, and sampling efficiency. In addition, an intercomparison between two laboratories was conducted. No multibed configurations were tested. Of the sorbent materials Tenax TA showed acceptable results for these BVOCs, while with Carbopack B losses and increases in some compounds were detected. Studied compounds were found to be stable in Tenax TA tubes for at least 1 month at −20 and at +20 ∘C. Breakthrough tests indicated that α- and β-pinene have clearly lower breakthrough volumes in the Tenax TA tubes used (4–7 and 8–26 L, respectively) than other terpenes (&gt; 160 L). SS, SilcoNert 1000 and glass were all shown to be suitable tube materials. Results from Tenax TA sorbent tube sampling agreed with online sampling for most compounds. Heated SS tubes, sodium thiosulfate filters and KI/Cu traps were found to be suitable ozone scrubbers for the studied BVOCs. Tested particle filters had a greater impact on limonene (relative difference &lt; +7 %) than on α- and β-pinene (relative difference ±2 %). The laboratory intercomparison of α- and β-pinene measurements showed that in general, measured values by the two laboratories were in good agreement with Tenax TA.

Uncharacteristic Adsorption Breakthrough Behavior of a Core–Shell Copper Hydroxysulfate Metal–Organic Framework Against Gaseous Formaldehyde

AbstractCore–Shell structured microspheres with a packed nano‐platelet copper hydroxysulfate (CHS) core and an octahedral crystalized metal–organic framework‐199 (CHS@M199) shell are synthesized and tested as adsorbent for gaseous formaldehyde (FA). CHS@M199 outperforms reference materials (e.g., activated carbon (AC), CHS, and M199) with adsorption capacity (Q) of 8.13 mg g−1 and partition coefficient (PC) of 0.263 mol kg−1 Pa−1 against 10 Pa FA at 10% breakthrough (BT) level with the aid of large surface area and copper sites for coordinating with carbonyl group. Contrary to general expectations, CHS@M199 exhibits a unique adsorption behavior in that BT volume increases systematically with the rise in FA inlet partial pressure (e.g., 5–10 Pa). The 10% BT capacity of CHS@M199 decreases noticeably (8.13 to 2.08 mg g−1) with increasing relative humidity (0.016 to 10%), reflecting water‐FA competition for hydrophilic adsorption sites. Although FA adsorption on CHS@M199 diminishes with elevated RH levels, such reduction intensifies when simulating ambient conditions (through stepwise addition of competing components: O2, CO2, and H2O). The FA adsorption on CHS@M199 is well described by both pseudo‐first‐order (PFO) and pseudo‐second‐order (PSO) kinetics. Polymerization may play a pivotal role in the adsorption of FA on CHS@M199, as Qi‐LeVan isotherm best fits the experimental data.

A New Language for a New Perception: A Study of the Influence of Chinese Poetry on the Composition of Spring and All

Abstract This essay highlights the numerous evidences of Chinese influences on Williams’s poetry, and particularly on the composition of Spring and All. What was it in Chinese poetry that could help Williams accomplish his poetic modernization which Pound was urging him to perform? In which ways and to which extent did Williams use Chinese poetic forms and concepts to compose his modernist masterpiece? As a continuation of the research of Wai-Lim Yip and Zhaoming Qian, two of the very few scholars who have focused their attention on this topic, this essay asks how much of what is seen by Western critics as poetic innovations by Williams can actually be seen as appropriations or derivations from Chinese language and poetics. It highlights that many of the poetic devices used in Spring and All, Williams’s breakthrough volume as a modernist, are actually either borrowed from traditional Chinese poetics, or result from the fusion of the English language with ideogramic linguistic concepts.

A novel blending nanofibrous membrane of Poly(ionic liquid) for efficient and fast adsorption of ReO4−

Efficient recovery of rare scattered metal Re(VII) from various resources is a prerequisite due to its important application. Herein, a type of novel nanofibrous membrane, 0.4P(Ph-3MVIm-Br)-3PVP/2TPU, is successfully prepared by electrospinning, where poly(ionic liquid) P(Ph-3MVIm-Br) is incorporated and could supply more adsorption sites. Meanwhile, PVP (polyvinyl pyrrolidone) and TPU (thermoplastic polyurethane) ensured the water flux and the structural stability of the membrane. The nanofibrous membrane exhibited a high adsorption capacity for ReO4−, which can reach 128 mg g−1 at pH 5. Its water flux is as high as 433 L m−2 h−1 at 0.4 g of poly(ionic liquid) addition, membrane thickness of 20 μm, and pressure of 1 bar. Furthermore, 0.4P(Ph-3MVIm-Br)-3PVP/2TPU nanofibrous membrane can remove 91.7% of ReO4− within 30 min. After 9 times recycling, the adsorption efficiency of the membrane can still maintain more than 90%. Dynamic ReO4− removal with 0.4P(Ph-3MVIm-Br)-3PVP/2TPU after one cycle was accomplished with a breakthrough volume of 24 mL ReO4− solution (feed 10 mg L−1, 100 mg membrane). The exchange of ReO4− and Br− of poly(ionic liquid) mostly promote the adsorption of ReO4−. Moreover, the structure of the membrane has excellent selectivity, mechanical performance, strong acid and alkali resistance stability, which endow the membrane easy to operate in practical applications.

Exfoliated MXene/poly-melamine-formaldehyde composite membranes for removal of heavy metals and organics from aqueous solutions

Heavy metal ions and organic pollutants discharged into various water bodies have caused serious water pollution, and the efficient removal of these contaminants remains a challenge. Here, we report a novel MXene/poly-melamine-formaldehyde (PMF) composite membrane, in which the PMF particles serve as spacers, and the –NH2 groups of PMF and the hydroxyl groups of MXene nanosheets have a synergistic effect on the adsorption of pollutants, and the crosslinking of glutaraldehyde inhibits the swelling of the composite membrane. The MXene/PMF composite membrane with 83.7% PMF particle loading displays a water permeability of 381.2 L m−2 h−1 bar−1 (405% that of MXene membrane) and excellent adsorption ability. In static adsorption, the removal rates of Zn2+, Pb2+, phenol, and crystal violet reach 96.2%, 91.7%, 99.1%, and 96.4% respectively, 20∼100% higher than those of MXene membranes. In dynamic adsorption, the breakthrough volumes of the membrane for 2 ppm p-nitrophenol solution and methyl blue solution reach 75 mL (about 8500 times membrane volume) and 350 mL (about 39800 times membrane volume), and the saturation volumes are 1500 mL and 5000 mL, respectively. After cyclic adsorption/desorption for four times, the removal rate of the membranes still maintains above 90%. This work provides an efficient composite membrane for removing pollutants from wastewater.

Sampling efficiency of a polyurethane foam air sampler: Effect of temperature

Effective monitoring of atmospheric concentrations is vital for assessing the Stockholm Convention's effectiveness on persistent organic pollutants (POPs). This task, particularly challenging in polar regions due to low air concentrations and temperature fluctuations, requires robust sampling techniques. Furthermore, the influence of temperature on the sampling efficiency of polyurethane foam discs remains unclear. Here we employ a flow-through sampling (FTS) column coupled with an active pump to collect air samples at varying temperatures. We delved into breakthrough profiles of key pollutants, such as polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), and organochlorine pesticides (OCPs), and examined the temperature-dependent behaviors of the theoretical plate number (N) and breakthrough volume (VB) using frontal chromatography theory. Our findings reveal a significant relationship between temperature dependence coefficients (KTN, KTV) and compound volatility, with decreasing values as volatility increases. While distinct trends are noted for PAHs, PCBs, and OCPs in KTN, KTV values exhibit similar patterns across all chemicals. Moreover, we establish a binary linear correlation between log (VB/m3), 1/(T/K), and N, simplifying breakthrough level estimation by enabling easy conversion between N and VB. Finally, an empirical linear solvation energy relationship incorporating a temperature term is developed, yielding satisfactory results for N at various temperatures. This approach holds the potential to rectify temperature-related effects and loss rates in historical data from long-term monitoring networks, benefiting polar and remote regions.

The Black Aesthetic in Rita Dove’s Playlist for the Apocalypse

To Rita Dove, a renowned poet of great transformations and eclectic artistry, blackness is an aesthetic that must be embraced and celebrated. It is the project of this paper to reflect on the black aesthetic depicted in Rita Dove’s Playlist for the Apocalypse (2021); a breakthrough volume presenting blackness as an “Ars Poetica” an “X marks the spot” leading to Dove’s signature crossing. In this volume, Dove presents a playlist of the everyday and of the nation's history over the past fifty years. The title of the volume, while acknowledging the sequential playfulness of a music playlist, it maintains a cadence of finality brought about by the word “apocalypse.” Playlist for the Apocalypse presents “a lifetime of song” dramatizing Dove’s view of the idea of the apocalypse as both end and resurrection recorded in personal triumphs and pains as her stories meet with the grand arc of history. Keywords: Black aesthetic, grand arc of history, music, vocalization, orchestration, memory, race, anger, resignation, disease, death, resurrection

A new wormhole mechanistic model for radial acid flow geometry using novel 3D flow correlations

In carbonate reservoirs, matrix acidizing is used to improve well performance by creating conductive channels called wormholes. Predicting wormhole propagation rate in radial acid flow geometry up to the real wellbore scale is the main problem regarding designing field operations in previous studies which are still challenging. In this study, a new mechanistic approach is presented to predict the radial flow acidizing up to near wellbore scale by considering the vital effects of porous media size and geometrical parameters of wormhole patterns.Accordingly, wormhole tip velocity and wormhole wall fluid loss rate will be introduced as the scale transferring parameters between different porous media sizes which are correlated in terms of rock diameter and wellbore height, wormhole size and density. These novel correlations are extracted from the large databank of flux distribution between rock matrix and wormhole channel obtained in 60 different 3D FEM flow simulations for various patterns of wormhole propagating and different wellbore sizes. In addition, an HPHT radial acid flooding setup is designed and constructed to perform radial acid coreflood on ultra-low permeable rocks (k«1md) for model validation. During the experiments, the breakthrough pore volume, pressure behavior and CT scan of samples are closely monitored. The results showed that due to the tight window of pore size distribution, faster breakthroughs with 1.23 and 1.45 pore volumes occurred in these tight samples compared to those reported already which are confirmed by developed model prediction. Besides, the model results showed that increasing the rock height (open-hole interval) would increase wormhole tip velocity and decrease acid breakthrough time. In addition, the higher temperature shifted the acid response curve to the right, toward higher acid breakthrough volume and higher acid concentration shifted it toward lower breakthrough volumes. The model is validated using radial acid experiments and previous radial acid models for different rock sizes with good agreement (R2 = 0.9547, MSE = 0.02161 and RMSE = 0.14701). The new radial acidizing model is capable to quickly predict wormhole propagation rate up to wellbore scale without requiring excess up-scaling data due to considering wide ranges of porous rock sizes from (25.4–152.4 cm) diameter and (5–25.4 cm) pay zone height (sufficient size for considering repetitive wormhole patterns). This technique can be utilized for tuning parameters of various radial cases to predict the acid tests results leading to reduce the number of required experiments.