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[Display omitted] • Carbon nanofibrous membranes were prepared for adsorptive separation of VOCs. • The membranes showed hierarchical porous structures and functional surfaces. • The membranes possessed comparable adsorption quantities and fast kinetics. • The membranes exhibited good reusability and dynamic adsorption performance. Volatile organic compounds (VOCs) in the air pose great health risks to humans and the environment. Adsorptive separation technology has proven effective in mitigating VOC pollution, with the adsorbent being the critical component. Therefore, the development of highly efficient adsorbent materials is crucial. Carbon nanofibers, known for their physical–chemical stability and rapid adsorption kinetics, are promising candidates for removing VOCs from the air. However, the relatively simple porous structures and inert surface chemical properties of traditional carbon nanofibers present challenges in further enhancing their application performance further. Herein, a hierarchical porous carbon nanofibrous membrane was prepared using electrospinning technology and a one-step carbonization & activation method. Phenolic resin and polyacrylonitrile were used as co-precursors, with silica nanoparticles serving as the dopant. The resulting membrane exhibited a specific surface area of up to 1560.83 m2/g and surfaces rich in functional O-/N- groups. With a synergistic effect of developed micro- and meso -pores and active chemical surfaces, the carbon nanofibrous membrane demonstrated excellent adsorption separation performance for various VOCs, with comparable adsorption capacities and fast kinetics. Moreover, the membrane displayed remarkable reusability and dynamic adsorption performance for different VOCs, indicating its potential for practical applications. [ABSTRACT FROM AUTHOR]

Because of micro/nanoscale manipulation and task-performing capability, micro/nanomotors (MNMs) have attracted lots of research interests for potential applications in biomedical and environmental applications. Owing to the low-cost, good motion behavior, and environmental friendliness, various low-cost metal oxides based MNMs become promising alternatives to the precious metal based MNMs, in particular for environmental remediation applications. Hereby, we demonstrate the facile and scalable fabrication of two types of bubble-propelled iron oxides-MnO 2 core–shell micromotors (Fe 3 O 4 -MnO 2 and Fe 2 O 3 -MnO 2) for pollutant removal. The Fe 2 O 3 -MnO 2 micromotor exhibits efficient removals of both aqueous organics and suspended microplastics via the synergy of catalytic degradation, surface adsorption, and adsorptive bubbles separations mechanisms. The adsorptive bubbles separation achieved more than 10% removal of the suspended microplastics from the polluted water in 2 h. We clarified the major contributions of different remediation mechanisms in pollutants removals, and the findings may be beneficial to a wide range of environmental applications of MNMs. [ABSTRACT FROM AUTHOR]

Efficient separation of Xenon (Xe) and Krypton (Kr) is a significant process for their wide industrial applications and potential environmental concerns. Owing to the inert atomic gases (Xe and Kr) nature with similar physical and chemical properties, it is a great challenge to achieve efficient separation of the Xe/Kr mixture. Herein, we report a series of microporous lanthanide based metal-organic frameworks Ln (BTC) (H 2 O)·(DMF) 1.1 (Ln-MOF) (Dy-BTC (1), Er-BTC (2), and Yb-BTC (3)) with ultrahigh thermal stability for adsorptive Xe/Kr separation. These three isostructural Ln-MOFs consisted of lanthanide metal ions and 1,3,5-benzene dicarboxylate ligands that possess a square channel with pore sizes of 6–7 Å. By substitution of Ln ions, Yb-BTC shows the smallest pore size among the three compounds which enables its obvious higher Xe/Kr selectivity compared with the other two Ln-MOFs. Yb-BTC exhibits a moderately high Xe uptake of 2.5 mmol/g (298 K and 1 bar), and a significantly high Xe/Kr uptake ratio of 3.8, indicative of its great potential for separation of Xe/Kr mixture. The effective Xe/Kr separation ability of Yb-BTC was also confirmed by a breakthrough experiment. The adsorption separation diagram of Xe/Kr mixture in the material shows that Xe is fully adsorbed and Kr is not adsorbed. [Display omitted] • The materials have high thermal stability, and is stable at 600 °C. • Yb-BTC shows higher Xe/Kr selectivity compared with other two Ln-MOFs. • Ln-BTC has a moderately high Xe adsorption capacity and a significantly high Xe/Kr uptake ratio. • Yb-BTC exhibits obvious higher IAST Xe/Kr selectivity than Dy-BTC and Er-BTC. [ABSTRACT FROM AUTHOR]

Abstract The emerging organic micro-pollutants, such as bisphenol A (BPA), chloroxylenol (PCMX) and carbamazepine (CBZ), have raised concerns owing to their adverse impact on human health and ecological security. In this study, a novel cyclodextrin polymer (β-CDP) has been successfully prepared by nucleophilic substitution of β-cyclodextrin with tetrafluoroterephthalonitrile (TFP). The removal of three emerging organic micro-pollutants (BPA, CBZ and PCMX) by β-CDP under a single or mixture adsorption system was examined, and the adsorption behavior was investigated by adsorption kinetics and isotherm study. The maximum adsorption capacity of β-CDP for BPA, PCMX and CBZ according to Langmuir isotherm in single system was 164.4, 144.1 and 136.4 mg/g, respectively. Compared with single system, the competitive adsorption of each pollutant on β-CDP in mixture system was only slightly inhibited. Changing the pH, raising the presence of fulvic acid (FA) or ionic strength had no significant influence on the adsorption of BPA, PCMX and CBZ onto β-CDP. The removal of these three organic micro-pollutants was related to the value of logK ow of the contaminants. These results demonstrated remarkable advantages of β-CDP material relevant to organic micro-pollutants removal in wastewater treatment. Graphical abstract fx1 Highlights • A novel practical β-CDP adsorbent was successfully synthesized. • β-CDP could simultaneously adsorb BPA, CBZ and PCMX. • These three pollutants were entrapped by the cavities of β-CDP. • The adsorption of these pollutants was largely unaffected by Na and Ca ions. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract This investigation is based on experimental data to deeply understand the unusual adsorption behavior of the flexible MIL-53s in aqueous solution. In contrast to the strongly flexible MIL-53(Cr) and MIL-53(Al) with large pore form (lp) in water and in their anhydrous state, MIL-53(Fe) exhibits narrow pore form (np) or very narrow pore form (vnp), indicating that breathing effect depends on the nature of the metal. Sulfamethoxazole (SMZ) adsorption results demonstrated that the maximum adsorption capacities predicted by Langmuir model were 1.85, 1.78 and 0.314 mmol/g for MIL-53(Cr), MIL-53(Al), and MIL-53(Fe), respectively. The adsorption equilibrium was rapidly reached within 60 min and the kinetic data best fitted with the pseudo second order model. The lp form of MIL-53(Cr) and MIL-53(Al) in aqueous solution provided the easy entrance for contaminants, lead to lower binding energy and caused modifications of the hydrophobic/hydrophilic character, which all enhanced their adsorption capacities for SMZ. However, the np form of MIL-53(Fe) with small inner pores and hydrophilicity compromised its adsorption capacity for SMZ. The experimental results revealed electrostatic interactions, hydrogen bonding, and π-π interaction/stacking contributed to the adsorption of SMZ on MIL-53s as well. In summary, the complexation of different metal nodes to MOFs is accompanied by the diversity of properties, which significantly affect their adsorptive performance. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract A polyoxomolybdate based hybrid, [ δ -Mo 8 O 26 ](L) 2 ·2H 2 O (BUC-77), was synthesized via hydrothermal method, which exhibited selectively fluorescent detection and efficient adsorptive removal toward Pb2+ in aqueous environment. A good linearity was observed between the fluorescence quenching percentage of BUC-77 and the Pb2+ concentration, along with the detection limit being 6.91 ppb. BUC-77 was stable in common solvents and wide pH range, which could be regenerated by being washed with dilute inorganic acids like HNO 3 after adsorption of Pb2+. The results revealed that BUC-77 could be potentially used to achieve both detection and removal of Pb2+ in wastewater. [ABSTRACT FROM AUTHOR]

Microsampling is an attractive option for significantly reducing the volume of blood taken for chemical analysis allowing for blood samples taken as a ‘finger-prick’ with a lancet. A novel, volumetric adsorptive microsampling (VAMS™) device, which reproducibly collects a small volume of 10 μL whole blood in a hematocrit-independent manner, is evaluated in a human biomonitoring setting, and has been utilized for analysis of several perfluoroalkyl acids (PFAA). The results show that the VAMS technique is applicable for PFAA analysis, method has good linearity, repeatability, accuracy and is sufficiently sensitive for samples from general populations. The stability of PFAAs with VAMS devices is shown to be acceptable, which supports the sampling and transportation strategy of several study designs. Furthermore, as well as allowing for a quick and efficient extraction and analysis flow path, the VAMS microsampler is an easy to use device in a real-world sample collection scenario. [ABSTRACT FROM AUTHOR]

Arsenic-contaminated water has significant adverse impacts on human health and ecosystems. We developed a new adsorptive membrane by modifying the porous support layer of a phase inversion formed membrane for arsenic removal. Iron oxide (Fe 3 O 4 ) microspheres were immobilized in the support layer of the membrane by reverse filtration, followed by dopamine polymerization. The prepared adsorptive membrane was compared with a virgin membrane without Fe 3 O 4 microspheres and a Fe 3 O 4 blended membrane in terms of membrane structures and separation performance. The adsorptive membrane prepared by our new method had comparable water permeability and rejection performance with the virgin membrane without Fe 3 O 4 microspheres, but higher rejection performance and dynamic adsorption capacity than the membrane prepared by the conventional blending method. Both static and dynamic adsorption modes were used to evaluate the adsorption performance of the membranes. Our new adsorptive membrane also had excellent regeneration performance. After three regeneration cycles, the membrane was still capable of treating more than 2 tons of As-contaminated water/m 2 . The adsorptive membrane of 1 m 2 could treat over 7 tons of water to the drinking water standard in terms of arsenic concentration during three regeneration cycles. Therefore, our adsorptive membrane may pave a new way for arsenic removal from water and ensuring drinking water security. [ABSTRACT FROM AUTHOR]

Adsorptive removal of a toxic sulfonamide antibiotic, sulfachloropyradazine (SCP), from aqueous solution was studied on several metal organic frameworks, UiO-66 and ZIF-67, for the first time. UiO-66 exhibited a much higher adsorption capacity than ZIF-67, fast kinetics, and easy regeneration for reuse, demonstrating as a promising adsorbent in wastewater treatment processes. The batch adsorption shows an adsorption capacity of SCP at 417 mg/g on UiO-66. The kinetic adsorption of SCP on UiO-66 reached equilibrium just in 10 min and the kinetics fits accurately with a pseudo 2nd order model. A plausible mechanism was proposed based on pH effect, p K a value of the adsorbate and Zeta potential of UiO-66. The high adsorption is mainly contributed to hydrophobicity and π-π interactions along with electrostatic interactions. Thermodynamic studies show the spontaneous adsorption and exothermic process. The easy regeneration and high adsorption capacity confirms structural stability of the robust UiO-66 in wastewater treatment processes, making it suitable for a large scale application. [ABSTRACT FROM AUTHOR]

Mesoporous materials have significant potential for use as adsorbents for removal of phosphate from water. The chemical and structural properties of materials greatly affect their capacity and rate in the phosphate adsorption process. This paper reviews recent activities in the development of mesoporous materials as phosphate adsorbents. In particular, it mainly focuses on the synthesis, properties and phosphate removal efficiency of various materials with mesoporosity, including metal-coordinated amino-functionalized silicas, ammonium-functionalized silicas, metal-doped mesoporous silicas, metal oxides, metal sulfate and carbon. [ABSTRACT FROM AUTHOR]

In this work, we present material chemistry in the hydrothermal synthesis of new complex structure materials based on various dosage ratios of Fe and Ce (1:0, 2:1, 1:1, 1:2, 0:1), characterize them by the relevant methods that allow characterization of both crystalline and amorphous phases and correlate their structure/surface properties with the adsorptive performance of the five toxic anions. The applied synthesis conditions resulted in the formation of different compounds of Fe and Ce components. The Fe-component was dominated by various phases of Fe hydrous oxides, whereas the Ce-component was composed of various phases of Ce carbonates. The presence of two metal salts in raw materials resulted in the formation of a mesoporous structure and averaged the surface area compared to one metal-based material. The surface of all Fe-Ce composites was abundant in Fe component phases. Two-metal systems showed stronger anion removal performance than one-metal materials. The best adsorption was demonstrated by Fe-Ce based materials that had low crystallinity, that were rich in phases and that exhibited surfaces were abundant in greater number of surface functional groups. Notably, Fe extended fine structures simulated by EXAFS in these better adsorbents were rich from oscillations from both heavy and light atoms. This work provides new insights on the structure of composite inorganic materials useful to develop their applications in adsorption and catalysis. It also presents new inorganic anion exchangers with very high removal potential to fluoride and arsenate. [ABSTRACT FROM AUTHOR]

Abstract: Using the solution phase method without any surfactants or templates, the hierarchical of Cu2Cl(OH)3 microspheres were synthesized by freeze drying. The size and surface area of the microspheres are ca. 1–2µm and 76.61m2 g−1, respectively. A possible formation mechanism is presented based on the experimental results. Methylene blue was chosen to investigate the adsorption capacity of the as-prepared adsorbent. The effects of various experimental parameters, such as pH, initial dye concentration, and contact time were investigated. The results showed that the dye removal increased with the increasing in the initial concentration of the dye and also increased in the amount of microspheres used and initial pH. Adsorption data fitted well with the Freundlich adsorption isotherm. The thermodynamic analysis presented the exothermic, spontaneous and more ordered arrangement process. The microspheres could be employed effective for removal of dyes from aqueous solution. [Copyright &y& Elsevier]

We have studied the synergetic effect of confinement (carbon nanopore size) and surface chemistry (the number of carbonyl groups) on CO2 capture from its mixtures with CH4 at typical operating conditions for industrial adsorptive separation (298K and compressed CO2—CH4 mixtures). Although both confinement and surface oxidation have an impact on the efficiency of CO2/CH4 adsorptive separation at thermodynamics equilibrium, we show that surface functionalization is the most important factor in designing an efficient adsorbent for CO2 capture. Systematic Monte Carlo simulations revealed that adsorption of CH4 either pure or mixed with CO2 on oxidized nanoporous carbons is only slightly increased by the presence of functional groups (surface dipoles). In contrast, adsorption of CO2 is very sensitive to the number of carbonyl groups, which can be examined by a strong electric quadrupolar moment of CO2. Interestingly, the adsorbed amount of CH4 is strongly affected by the presence of the co-adsorbed CO2. In contrast, the CO2 uptake does not depend on the molar ratio of CH4 in the bulk mixture. The optimal carbonaceous porous adsorbent used for CO2 capture near ambient conditions should consist of narrow carbon nanopores with oxidized pore walls. Furthermore, the equilibrium separation factor was the greatest for CO2/CH4 mixtures with a low CO2 concentration. The maximum equilibrium separation factor of CO2 over CH4 of ∼18–20 is theoretically predicted for strongly oxidized nanoporous carbons. Our findings call for a review of the standard uncharged model of carbonaceous materials used for the modeling of the adsorption separation processes of gas mixtures containing CO2 (and other molecules with strong ... [ABSTRACT FROM AUTHOR]

Abstract: Adsorptive separations of C2H6/CH4 and CH4/N2 binary mixtures are of paramount importance from the energy and environmental points of view. A mesoporous carbon adsorbent was synthesized using a soft template method and characterized with TEM, TGA, and nitrogen adsorption/desorption. Adsorption equilibrium and kinetics of C2H6, CH4, and N2 on the mesoporous carbon adsorbent were determined at 278, 298, and 318K and pressures up to 100kPa. The adsorption capacities of C2H6 and CH4 on the mesoporous carbon adsorbent at 298K and 100kPa are 2.20mmol/g and 1.05mmol/g, respectively. Both are significantly higher than those of many adsorbents including pillared clays and ETS-10 at a similar condition. The equilibrium selectivities of C2H6/CH4 and CH4/N2 at 298K are 19.6 and 5.8, respectively. It was observed that the adsorption of C2H6, CH4, and N2 gases on the carbon adsorbent was reversible with modest isosteric heats of adsorption, which implies that this carbon adsorbent can be easily regenerated in a cyclic adsorption process. These results suggest that the mesoporous carbon studied in this work is a promising alternative adsorbent for the separations of C2H6/CH4 and CH4/N2 gas mixtures. [Copyright &y& Elsevier]

Acetylene is an important chemical feedstock that is very challenging to separate/purify from the common impurity CO 2 generated during the manufacture processes. Adsorptive separation by porous material is environmentally friendly and energy efficient, and therefore is regarded as an attractive approach. The microporous MOF Cu 2 (ade) 2 (PA) 2 (ade ​= ​adenine, PA ​= ​propionic acid) with accessible basic sites was evaluated for C 2 H 2 /CO 2 separation. The C 2 H 2 adsorption capacity and C 2 H 2 /CO 2 selectivity are comparable to those of the benchmark materials making this material promising candidate for the important C 2 H 2 /CO 2 separation. Selective C 2 H 2 ​adsorption over CO 2 ​by a microporous MOF with rich basic functional sites. Image 1 [ABSTRACT FROM AUTHOR]

The low surface area of TiO 2 (50 m2g-1 - Degussa P25) due to randomly oriented, agglomerated nanostructures and charge carrier recombination tendency, has till date been its major limitation for photocatalytic remediation of polluted wastewater. This study presents an innovative process to design super porous TiO 2 nanostructures with high effective surface area (238 m2g-1), robust, structurally ordered mesoporosity via a simple sol-gel assisted reflux method. Detailed material characterization studies suggest that the higher degree of intermolecular ligation in novel templates such as butanetetracarboxylic or tricarballylic acid modified titanium hydroxide gels resulted in retainment of the porous structure during the urea assisted combustion synthesis. The induction of robust structural porosity is accompanied by a reduction in pore size distribution, an increase in pore volume leading to significantly higher total surface area of the synthesized TiO 2. Detailed investigation of dye adsorption kinetics and photocatalytic degradation kinetics, complemented by kinetic modeling analysis confirmed that the super porous TiO 2 with robust mesoporous structure outperforms the rest of synthesized TiO 2 catalyst (having only agglomerate porosity) in terms of its superior adsorption capacity, faster diffusion kinetics and photocatalytic activity for degradation of Amaranth dye. Thus, the super porous TiO 2 shows promising potential for application in sustainable photocatalytic technology for remediation of wastewater contaminated with azo dyes. Image 1 • Super porous TiO 2 with robust structural mesoporosity, enhanced surface area has been synthesized. • Ti(OH) 4 gels have been innovatively modified with butanetetracarboxylic acid and urea to transform agglomerate porosity in to robust, structural mesoporosity. • Significant improvements in the Amaranth dye adsorptive separation capacity and photocatalytic degradation efficiency have been measured. • Detailed kinetic modeling analysis, signify the potential of super porous TiO 2 for application in self-sustainable photocatalytic water purification technology. [ABSTRACT FROM AUTHOR]