Separations, Volume 10, Issue 12 (December 2023) – 24 articles

A comparative study of a Schiff base reaction involving benzaldehyde and n-butylamine was carried out to improve the yield of the resulting imine. This reaction was carried out at different temperatures without and with the elimination of the water produced during the process by the pervaporation (PV) technique using a typical cylindrical cell. To reach this goal, different dense membranes made of crosslinked poly(vinyl alcohol) with different oxalic acid (crosslinker) contents were prepared by the solvent casting method. Different parameters influencing the performance of the membrane in the separation process including swellability, diffusivity, crosslinking density, and thermal properties were investigated. The total and partial cumulative transmembranar fluxes as well as the separation factor were studied and the separation process was monitored by HPLC analysis. The n-butyl-1-phenylmethanimine produced was characterized by FTIR and ¹HNMR analyses. The results obtained were a clear improvement in the yield of the reaction. For example, the yield obtained from the Schiff base reaction occurring without assistance by PV varied from 58 to 84 wt% when the temperature changed from 5 to 45 °C. On the other hand, when the PV process was used to eliminate water from this reaction mixture, the yield went from 90.4 to 98.6% by weight in this same temperature order. The cumulative total and partial fluxes significantly decreased with time. On the other hand, the separation factor reached a maximum at about one hour at 5, 15, and 45 °C. At 25 °C, the maximum total flux was reached at about 2 h of the PV process. The best selectivity of the PVA-0.5 membrane with regard to water was obtained at 15 °C. It was also revealed from the results obtained that the cumulative total and partial flux decreased rapidly with time and the separation factor reached a maximum at one hour into the PV process, in which 1.51 × 10⁴ was reached at 15 °C, 6.25 × 10³ and 3.50 × 10³ at one hour of the separation process, and 10.23 × 10³ at 25 °C at 2 h of the water removal by PV. Full article

Drynariae Rhizoma (DR) is a functional food and traditional medicine that has been widely used for bone and joint disorders for thousands of years. In this study, 14 compounds were isolated from DR, and their structures were identified using UPLC/QTOF–MS, UPLC–ESI/LTQ–Orbitrap–HRMS, and 2D NMR and compared with those obtained in previous studies. An HPLC–PDA multi-component simultaneous quantitative determination method was developed for 12 of the 14 DR-derived compounds, excluding compounds with a content <1.5 mg. The developed HPLC method was validated based on linearity (r² ≥ 0.999), limit of detection (0.01–0.65 μg/mL), limit of quantification (0.04–1.97 μg/mL), intra-day precision and accuracy ranges (0.06–2.85% and 95.03–104.75%, respectively), and inter-day precision and accuracy ranges (0.24–2.83% and 95.75–105.75%, respectively). The developed analysis method improved the resolution of compounds 4 and 5. In addition, this is the first quantitative analysis of compounds 7, 8, and 11 and the first simultaneous quantitative analysis of 12 compounds, including compounds 4, 7, 8, 10, 11, and 14. This study developed a rapid, accurate, and economical HPLC method for performing the simultaneous quantitative analysis of 12 secondary metabolites isolated from DR. Full article

Metal(IV) phosphate and phosphonates materials have increasingly found their applications in water purification, heterogeneous catalysis, drug delivery, and proton-exchange membrane fuel cells. The strong linkage between tetravalent metal cations and phosphate/phosphonate groups offers a unique bottom-up design platform, resulting in chemically stable inorganics or hybrids. Task-specific physiochemical functionalities could be deposited by modifying the phosphate/phosphonate groups before the material synthesis. The high reactivity between the metal centre and the phosphorus-containing linker, on the other hand, often leads to obtaining unordered materials (amorphous solids or coordination polymers). The chemical composition of the prepared materials is a key parameter in guiding the synthetic approach and in governing their performances. This narrative review focuses on critically summarising the traditional and advanced analytical methods for probing the composition of these materials. The reader is introduced to and guided on the advances and restrictions of different analysis techniques when probing metal(IV) phosphates/phosphonates. Both solution-based and solid-state spectroscopic techniques are covered with a focus on understanding the quantity and the linkage status of the phosphorus-containing moieties. These techniques include atomic spectroscopy, mass spectroscopy, nuclear magnetic resonance spectroscopy, X-ray-based methods, and neutron activation analysis. Full article

Due to their detrimental and carcinogenic effects, synthetic organic dyes pose significant environmental and health risks. Consequently, addressing the bioremediation of industrial wastewater containing these organic dyes has become an urgent environmental concern. The adsorption using low-cost and green materials is one of the best alternative techniques for the removal of dyes. This study aims to investigate the use of chitin to eliminate Congo red (CR), an anionic dye, from wastewater. The chitin was produced from shrimp shell in a quick and environmentally friendly manner by utilizing a co-solvent (glycerol/citric acid (GLC)). The resulting adsorbent was characterized through various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and FT-IR spectroscopy. The effectiveness of CR removal with chitin was studied with respect to contact time, adsorbent dose, initial pH, equilibrium isotherms, and kinetic and thermodynamic parameters. It was observed that variations in the dye concentration and pH significantly influenced the removal of CR with chitin. Under optimal operating conditions (pH = 7, contact time = 130 min, temperature = 50 °C), the adsorption capacity reached 29.69 ± 0.2 mg/g. The experimental data revealed that CR adsorption onto a chitin adsorbent is better represented by a Langmuir isotherm. Full article

There are many types of natural plants in nature that contain a variety of effective and complex chemical components. These constituents can be categorized as organic acids, volatile oils, coumarins, steroids, glycosides, alkaloids, carbohydrates, phytochromes, etc., all of which play important roles in the fields of pharmaceuticals, food, nutraceuticals, and cosmetics. The study of extraction and chemical composition analysis of natural products is important for the discovery of these active ingredients and their precursors. Therefore, the aim of this article is to review the status of research on the extraction, separation and purification, and structural identification of natural products, to provide a reference for the study of natural products. Full article

Nitrogen pollution in water bodies presents a serious threat to ecosystems due to its role in eutrophication. In this study, the aerobic denitrifying bacterium Alcaligenes faecalis was used as a model microorganism to investigate the optimal operating conditions for nitrogen removal from nitrogen-containing wastewater by Alcaligenes faecalis under different aeration modes, microbial dosages and C/N ratios. The results showed that the optimal aeration mode for efficient bacterial denitrification was 10 min of aeration with a 30 min interval, and the total nitrogen removal reached 87.82%. At different bacterial doses, NO₃⁻–N was completely denitrified and NO₂⁻–N accumulation levels were reduced, all of which resulted in significant denitrification, and the final total nitrogen removal efficiencies reached 86.39–98.50%. With an increase in the C/N ratio, the pollutant removal performance of denitrifying bacteria increased. When the C/N ratio was 17, the final rates of NO₃⁻–N, TN and COD removal were 100%, 98.50% and 96.13%, respectively. At lower C/N ratios, the growth and metabolism of microorganisms were inhibited and fewer electron acceptors were available during the denitrification process, which seriously affected denitrification performance. In this study, the denitrification performance of aerobic denitrifying bacterium Alcaligenes faecalis was explored in experiments using changes in aeration mode, microbial dosage and C/N ratio, and the optimal operating conditions of Alcaligenes faecalis for treating nitrogenous wastewater were indicated. This provides technical support for Alcaligenes faecalis in improving the remediation effect of nitrogenous wastewater and provides a theoretical basis for further in-depth research on the performance of Alcaligenes faecalis in the future. Full article

Essential oils (EOs), also called liquid gold, are known for their wide range of applications and biological activities. The modern use of EOs has received increasing attention for more than 60 years. The precious EOs have been refined from plant raw materials using a variety of methods. Since the extraction, separation, and purification methods determine the type, quantity, and stereochemical structure of EO molecules as well as the final yield and quality of EOs, the selection of an appropriate method is crucial. The traditional and emerging extraction methods (hydrodistillation, steam distillation, organic solvent extraction, etc.), as well as separation and purification methods (chromatography, macroporous resin, chemical reaction, etc.), of plant EOs and their main volatile compounds were shown. Our review focused on the principles, processes, characteristics, and applications of these methods, so as to better understand the preparation of pure plant EOs and further guide their large-scale use. Full article

Cyanobacterial blooms in freshwater bodies are mainly attributed to the excess loading of nutrients. The microbes in sediments may affect nutrient migration and transformation during the growth of cyanobacteria. This study focused on the role of Paraburkholderia disturbance in affecting the sediment nutrient conditions and further contributing to cyanobacterial community succession in Meiliang Bay, Lake Taihu. The dissolving phosphorus and fixing nitrogen of Paraburkholderia with different concentration and characteristic capabilities, as well as the impact on nutrients (nitrogen (N), phosphorus (P), iron (Fe), etc.) in eutrophic lakes were determined. The results indicated that the various forms of phosphorus in the sediments showed total phosphorus (TP) > inorganic phosphorus (IP) > iron/aluminum-bound phosphate (NaOH-P) > algal-available phosphorus (AAP) > organic phosphorus (OP) > calcium-bound phosphate (HCl-P). Additionally, it was observed that with higher values of Paraburkholderia (OD₆₀₀), the higher the corresponding risk of endogenous nutrient release from the sediments into the overlying water (but more is not always better), especially for the solubilization of HCl-P. The diffusion fluxes of TP, total nitrogen (TN) and Fe at the sediment–water interface (SWI) were all positive in the bacteria only experiment, with maximum values of 0.64, 15.0 and 5.02 mg/(m²d), respectively. Additionally, it was interesting that Paraburkholderia were able to produce organic acids, causing a decrease in pH. Furthermore, glucose levels can seriously affect water quality, especially the reduction in dissolved oxygen (DO) (down to 0.01 mg/L), leading to a series of side effects that have a huge impact on cyanobacterial community succession. These results provide a theoretical basis for the microbial ecological factors in eutrophic lakes. Full article

We analyzed ten pulses (the dried seeds of legumes), i.e., baby lima beans, black beans, black-eyed peas, butter beans, cranberry beans, garbanzo beans, green split peas, lentils, navy beans, and pinto beans, using three-dimensional liquid chromatography (3D-LC) with parallel second dimensions, LC × (LC + LC). We combined non-aqueous reversed-phase (NARP) chromatography as the first dimension separation, ¹D, with argentation UHPLC for separation based on degree and location of unsaturation in the first second dimension, ²D(1), and multi-cycle NARP-UHPLC in the second second dimension, ²D(2). Pulses contained 1.9% to 2.7% lipids, except garbanzo beans, which contained 6.2% lipids. High-resolution, accurate-mass (HRAM) orbitrap mass spectrometry (MS) was used to perform lipidomic analysis of the ²D(2) and percent relative quantification, showing that the most abundant average triacylglycerol (TAG) molecular species across all pulses were PLL at 10.67% and PLLn at 10.45%. Common beans (Phaseolus vulgaris) were clustered together using principal component analysis (PCA), showing the highest levels of linolenic acid, C18:3, in molecular species such as PLnLn, LLnLn, and OLLn, with palmitic (P), C16:0, linoleic (L), 18:2, linolenic (Ln), 18:3, and oleic (O), 18:1, FAs. Calibration curves derived from interweaved sets of regioisomer standards allowed the absolute quantification of 1,2- and 1,3-regioisomers for a subset of TAGs. Full article

Constructed wetlands (CWs) are a kind of green environmental protection technology, which are widely used in sewage treatment. Traditional CWs are faced with the problem of a low treatment effect of high-concentration sewage. In recent years, biochar, as a new type of adsorption material, has been used in CWs because of its advantages of large specific surface area, strong adsorption capacity, and wide material sources. This paper systematically summarized the characteristics of biochar and the preparation of biochar by studying the changes in microorganisms added to CWs and compared the effects of different treatment methods coupled with biochar on the treatment performance of CWs. The effects of biochar coupled with CWs on enzyme activity, functional genes, metabolites, and microbial communities were investigated. This review summarizes how different preparation methods affect the properties of biochar and how these biochar properties cause changes in the microorganisms added to CWs. It provides a new theoretical basis for the treatment of pollutants in CWs. Full article

Oil films on water are an increasingly major contamination problem worldwide. In 2020, we published a novel adsorption and transportation technology for oil–water separation based on biological role models like the floating fern Salvinia. This application provides an unexpected ability for the fast and efficient removal of oil films, particularly in ecologically important freshwater biota. A single small Bionic Oil Adsorber (BOA) with 1 m² functional textile can collect up to 4 L of oil per hour, which equals about 100 m² of oil film from a water surface into a collecting vessel. This is a safe, fast, and sustainable solution for the ubiquitous contaminations of, e.g., fuel oil in freshwater environments. Here, we present updated, new experimental data, and a review of the literature published since. Full article

Livestock and poultry farming, as a crucial component of agricultural production, poses a substantial threat to the ecological environment due to the discharge of wastewater. In recent years, researchers have proposed various resource treatment technologies for livestock and poultry breeding wastewater. However, a comprehensive discussion regarding the limitations and avenues for optimizing resource utilization technologies for livestock and poultry farming wastewater treatment is notably absent in existing literature. This paper takes swine wastewater as an illustrative case and undertakes a review of the advantages, disadvantages, and optimization directions of resource treatment technologies, including physical and chemical technology, microbial metabolism, microbial electrochemistry, constructed wetlands, and microalgae-based techniques. Based on mass balance, the recovery rates of various treatment technologies are estimated, and it was found that microbial electrochemistry and constructed wetland techniques may become the mainstream for resource utilization in the future. Furthermore, this paper emphasizes that in addition to resource efficiency, the optimization of resource utilization technologies for swine wastewater should also focus on the following aspects: (1) striking a balance between environmental impact and economic benefits; (2) reducing the cost of resource and energy utilization; and (3) safeguarding environmental and ecological security. Full article

Research on the efficient flotation desilication of low-grade magnesite is of great significance for the sustainable development of magnesium resources. Traditional collectors usually have some disadvantages, such as poor selectivity, severe environmental pollution, and weak water solubility. To strengthen the desilication flotation process of magnesite ore, the biodegradable surfactant, cocamidopropyl amine oxide (CPAO), was first utilized as the collector for the separation of the magnesite and quartz. The selective adsorption behavior and mechanism of the quartz and magnesite with the CPAO as the collector were studied through the micro-flotation experiments of the single mineral and the artificially mixed mineral, contact angle and atomic force microscopy (AFM) measurements, fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses. The flotation results indicated that the CPAO showed good selectivity and could effectively separate magnesite and quartz. When the concentration of the CPAO was 10.0 mg/L in the natural pulp pH (about 7.2), the concentrates with 97.67% MgO recovery and 45.62% MgO grade were obtained. The contact angle and AFM measurements indicated that the CPAO could selectively adsorb on the quartz surface rather than the magnesite surface to improve the interface difference between them, especially its surface hydrophobicity. The results of the FTIR and XPS analyses indicated that the CPAO is selectively adsorbed on the surface of the quartz, mainly through electrostatic interaction and hydrogen bonding. In conclusion, the CPAO had good selectivity and great potential as an effective collector in the reverse flotation desilication progress of magnesite. Full article

Alcohol and drug abuse is a major contributory factor of all road deaths in Europe. The aim of this study is to investigate the prevalence of alcohol and licit/illicit drug intake among victims of road accidents in Campania region (Italy). A retrospective analysis of road traffic deaths from 2013 to 2022 in Campania was performed. The toxicological results from fluid samples collected at autopsy were reviewed. In total, 228 road deaths occurred, mostly during nights and weekends. A total of 106 victims tested positive for alcohol and/or drugs, among which 39 (36.8%) tested positive for alcohol only, 27 (25.5%) for alcohol and drugs in association; and 40 (37.7%) for licit/illicit drugs only, either individually or in combination. Polydrug intake has been found in 21 victims, and nine in combination with alcohol. The most detected drugs were cocaine and Δ⁹THC, followed by benzodiazepines. Blood alcohol concentration (BAC) > 1.5 g/L was found in most alcohol positives, both alone and in association with drugs. Despite the penalties for driving under the influence of alcohol (DUI) and drugs (DUID), no decrease in the number of alcohol and/or drugs related fatal road accidents has been observed. DUI and/or DUID cases were approximately one third of the entire sample study. Full article

Qingkailing capsules are a classic traditional Chinese medicine prescription with remarkable clinical effects for the treatment of fevers. However, the chemical components of Qingkailing capsules are still unclear. To obtain and characterize the chemical profile of Qingkailing capsules, the present study applied a rapid, accurate, and sensitive method using ultra-high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry (UHPLC-FT-ICR-MS) to perform a comprehensive chemical characterization of Qingkailing capsules. Leveraging the high separation speed and good separation of UHPLC, the accurate mass data (within 5 ppm) and fragment ions, a total of 276 compounds, including 67 flavonoids and their glycosides, 52 organic acids, 75 terpenoids, 23 steroids, 22 phenylpropanoids, and 37 other compounds, were unambiguously or tentatively identified. This comprehensive analysis of the chemical components of Qingkailing capsules contributes to the quality evaluation and provides a scientific and reasonable basis for further study of prototype components and metabolites in vivo and pharmacological research, ultimately facilitating the advancement of Qingkailing capsules for further development and the therapeutic use of Qingkailing capsules in clinical applications. Full article

Olive leaves are naturally generated as a by-product during olive harvesting and olive oil production. Usually discarded with no specific use, they are a valuable source of bioactive compounds that should not be overlooked. Their valorization must therefore be achieved through the recovery of their polyphenols using an ecological strategy. Conventional extraction is commonly known as an energy- and solvent-consuming process, whereas emerging and innovative extraction technologies, such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pulsed-electric-field-assisted extraction (PEF), high-voltage-electric-discharge-assisted extraction (HVED), supercritical fluid extraction (SFE), infrared-assisted extraction (IAE), and “Intensification of Vaporization by Decompression to the Vacuum” (IVDV), are considered more sustainable and environmentally friendly. The aim of this review is to provide a comprehensive and updated overview of the valorization of olive leaves through both pretreatment and extraction techniques via an analysis of the recovered polyphenols and their potential applications. Full article

The disposal of industrial wastewater (IWW) discharged from factories is a significant topic in the environment field, and the use of cement-based materials is a useful way to treat materials with unexpected ions. In this work, IWW with abundant SO₄²⁻ collected from a factory was utilized to prepare cement mortar (IWWCM), and three kinds of nanomaterials (NMs), including nano-SiO₂ (NS), nano-CaCO₃ (NC), and nano-metakaolin (NMK), were used to improve the performance of IWWCM. The compressive strengths, hydration degree, hydration products, and micropore structure of the specimens were investigated. The test results showed that IWW reduced the strength of the specimens, and the use of NMs could compensate for this strength reduction. To be specific, the 28-day strength of the freshwater (FW) mixed specimen was 44.6 MPa, and the use of IWW decreased this value to 41.8 MPa. However, the strengths of the specimens with NMs were all higher than 50 MPa, indicating the advantage of NMs for the strengths of the IWWCMs. Moreover, the IWWCM showed a lower hydration degree with a poor pore structure, whereas the use of NMs in IWWCMs refined these properties, explaining the strength increase in the specimens. The results of the SO₄²⁻ content measurements also showed that the use of NMs could improve the SO₄²⁻ binding ratio, which is conducive to relieving the pressure of IWW disposal for industrial factories. Full article

This study aimed to investigate the influence of various production stages on the quality and spoilage conditions of traditionally dry-cured chorizo. To accomplish this, we employed an experimental design that examined three key production parameters: the batch, the filling stage, and the food smoking process. The study was conducted in collaboration with a local producer who adheres to traditional curing methods utilizing oak wood smoke and heat. Biogenic amine levels were closely monitored throughout the process. This involved their extraction and derivatization through the salting-out technique, followed by identification and quantification using LC-ESI/MSⁿ and HPLC-DAD, respectively. The findings suggest that both raw materials and the production process are well controlled during the filling stage. However, it became evident that the 14-day oak wood smoking period had a significant impact on biogenic amine formation, whose total mean values increased from 126 to 1385 mg kg⁻¹, particularly with respect to putrescine (PUT), cadaverine (CAD), and tyramine (TYR), although these levels remained below the oral toxicity limit (2000 mg kg⁻¹). Consequently, the concentration of these compounds can influence the quality and safety of traditionally dry-cured chorizos. Therefore, the combined levels of PUT, CAD, and TYR can serve as a valuable quality indicator for these products. Full article

Carbon–arsenic-bearing gold ore is a typical complex refractory gold resource. Traditionally, xanthate was often used as a flotation agent to separate gold minerals. But, in this paper, in order to reduce the cost of the agent, kerosene was used as an auxiliary collector, and the gold grade and recovery rate were increased by about 10 g/t and 5.5%, respectively. Through process mineralogy studies of the raw ore, it was found that the ore has an Au grade of 5.68 g/t, most of which is surrounded by sulfide ore, accounting for 79.46%. The main minerals are pyrite, arsenopyrite, and quartz, etc. Their content, shape, particle size distribution, and occurrence state were obtained via microscopic observation and statistical analysis. According to the results of process mineralogy, various flotation conditions were tested, including grinding fineness, kerosene dosage, collector dosage, foaming agent dosage, and the slurry pH value. The optimal chemical system and the process flow of “two roughing, three cleaning and two scavenging” were finally determined, and the concentrate product with a gold grade of 42.83 g/t and recovery of 91.02% was obtained, which verified the feasibility of the kerosene-assisted xanthate flotation of refractory gold. Full article

Oil sands process-affected water (OSPW) contains a diverse mixture of inorganic and organic compounds. Naphthenic acids (NAs) are a subset of the organic naphthenic acid fraction compounds (NAFCs) and are a major contributor of toxicity to aquatic species. Thousands of unique chemical formulae are measured in OSPW by accurate mass spectrometry and high-resolution mass spectrometry (MS) analysis of NAFCs. As no commercial reference standard is available to cover the range of compounds present in NAFCs, quantitation may best be referred to as “semi-quantitative” and is based on the responses of one or more model compounds. Negative mode electrospray ionization (ESI-) is often used for NAFC measurement but is prone to ion suppression in complex matrices. This review discusses aspects of off-line sample preparation techniques and liquid chromatography (LC) separations to help reduce ion suppression effects and improve the comparability of both inter-laboratory and intra-laboratory results. Alternative approaches to the analytical parameters discussed include extraction solvents, salt content of samples, extraction pH, off-line sample cleanup, on-line LC chromatography, calibration standards, MS ionization modes, NAFC compound classes, MS mass resolution, and the use of internal standards. Full article

The three-dimensional network and ample pore structure of novel hydrogel materials enable outstanding adsorption performance for pollutants such as methylene blue (MB) and Cr⁶⁺ ions in wastewater. In order to develop an environmentally friendly hydrogel with high adsorption performance and low cost, a type of carboxymethyl cellulose (CMC) composite hydrogel was synthesised with montmorillonite (MMT) via chain radical polymerization, which gives it great potential for application in the field of wastewater purification. A series of hydrogel samples were characterised through SEM, FTIR and nitrogen porosimetry analysis, indicating the successful intercalation of MMT nanosheets into the hydrogel crosslinking network. The mass ratio of CMC to MMT, the amounts of adsorbent, the initial concentration of wastes, pH, and the adsorption temperature were investigated and optimised for hydrogel adsorption performance. When the initial concentration of MB is 60 mg/L, pH is 7, the dosage of MB is 0.5 g/L, and the adsorption temperature is 30 °C, the hydrogel sample the highest adsorption capability for MB removal, with an adsorption amount of 112.9 mg/g. When the initial concentration of Cr⁶⁺ is 10 mg/L with a pH of 7, the highest adsorption capacity of the hydrogel for Cr⁶⁺ removal is 1.35 mg/g. The fitting results of the isothermal models, the kinetic models, internal particle diffusion models and the thermodynamics of the experimental data of the adsorbate adsorption process show that the adsorption of MB by hydrogel is a spontaneous segmented process of multi-layer physical and chemical adsorption. Additionally, the adsorption of Cr⁶⁺ ions by hydrogel is a spontaneous segmented process of multi-layer physical adsorption. Full article

Various porous polymer materials have been prepared for the separation of CO₂ from mixed gases. However, complex processes, expensive monomers, and costly catalysts are commonly used for their synthesis, making the adsorbents difficult to achieve in industrial applications. Herein, we developed a strategy to fabricate a series of benzene rings containing porous polymer materials (B-PPMs) via a facile condensation reaction of two inexpensive monomers, namely tetraphenylsilane and 1,4-bis(bromomethyl)benzene. The B-PPMs are verified to have accessible surface areas, large pore volumes, and appreciate pore sizes via a series of characterizations. The B-PPM-2 exhibits the best CO₂ adsorption amount of 67 cm³·g⁻¹ at 273 K and 1 bar, while the CO₂/N₂ selectivity can reach 64.5 and 51.9 at 273 K and 298 K, respectively. Furthermore, the adsorbent B-PPM-2 can be completely regenerated after five cycles of breakthrough experiments under mild conditions, which may provide promising candidates for selective capture of CO₂ from mixtures. Full article

Cathodic reduction is a green and promising remediation strategy for reducing the antibacterial activity of antibiotic contaminants and increasing their biodegradability. However, the lack of cost-effective electrocatalysts has restricted its application. In this study, we upcycled textile white mud by separating 1,4-dicarboxybenzene (BDC) and fabricating MIL-125(Ti)-derived amorphous TiO₂@C (TiO₂@C-W) as a functional electrocatalyst. The separated BDC from white mud shows lower crystallinity than BDC chemicals, but the resulting TiO₂@C-W features a much higher degree of oxygen vacancies and a 25-fold higher specific surface area than that of TiO₂@C derived from BDC chemicals. With florfenicol (FLO) as a probe, TiO₂@C-W exhibits similar cathodic reductive activity (0.017 min⁻¹) as commercial Pd(3 wt.%)/C (0.018 min⁻¹) does, which was 1.4 and 3.7 times higher than that of oxygen vacancy-engineered TiO₂ and TiO₂@C, respectively. The as-fabricated TiO₂@C-W could not easily remove FLO via the oxygen reduction reaction-based pathway with the applied bias for cathodic reduction. Though the activity of TiO₂@C-W undergoes a slight decline with continuous running, more than 80% of 20 mg L⁻¹ FLO can still be reduced in the eighth run. Water chemistry studies suggest that a lower initial solution pH boosts the cathodic reduction process, while common co-existing anions such as Cl⁻, NO₃⁻, HCO₃⁻, and SO₃²⁻ show a limited negative impact. Finally, TiO₂@C-W shows reductive activity against several representative antibiotics, including nitrofurazone, metronidazole, and levofloxacin, clarifying its potential scope of application for antibiotics (e.g., molecules with structures like furan rings, nitro groups, and halogens). This study couples the upcycling of textile white mud with the remediation of antibiotics by developing functional electrocatalysts, and offers new insights for converting wastes from the printing and dyeing industry into value-added products. Full article

A current subject of research is the application of magnetic effects for the detachment of accumulated particles of fibrous collectors in gas particle separation. Initial studies have already shown the magnetically induced detachment behavior of a compact particle structure after a single deflection from a single fiber. In this study, the detachment behavior of particle structures with different morphologies from a single fiber is investigated as a function of the particle loading stage on the fiber, the external magnetic flux density, the inflow velocity and the number of regenerations of the fiber for a certain parameter range. Diffusive and more compact particle structures with non-magnetic properties are deposited on the magnetizable single fiber. By applying an external magnetic field, the fiber is magnetized and experiences a torsional moment. The deposited particle structures on the fiber are detached by the acceleration forces. The detachment of the particle structures is observed using a high-speed camera and the image sequences are analyzed. By determining the projection area before and after the fiber deflection, a degree of regeneration is calculated. With magnetic-induced regeneration, high degrees of regeneration close to 100% can be achieved. Repetitive fiber deflections improve the detachment of the particle structures. The magnetic-induced regeneration is suitable for applications where flow reversal is not possible and can be performed either online or offline. Due to the gentle regeneration, fewer emissions are produced on the clean gas side than, for example, with jet pulse cleaning. It makes it easier to achieve emission limits and simplifies product recovery. Full article