Selective Adsorption Research Articles

Confined dual functionalized ionic liquids in metal-organic frameworks for selective NH3 adsorption

The capture and separation of ammonia (NH3), a typical hydrogen-rich, carbon-free, but highly corrosive and pungent odorous gas, is significantly important for resource utilization, sustainable development and environment protection. The combination of functionalized ionic liquids (ILs) and porous supports to develop novel porous composites for NH3 adsorption is an efficient way to achieve the above goals. In this work, dual functionalized IL (DFIL) simultaneously containing Lewis acidic sites and hydrogen bond sites supported porous Zr-MOF (Zr-bptc) with high stability and reversibility are developed for NH3 adsorption. The DFIL confined in the nanopores not only provides high NH3 affinity, but also reduces the pore size to form selective NH3 diffusion pathways. Thus, the highest NH3 adsorption capacity of 10.26 mmol/g at 1 bar and 25 °C was achieved by DFIL@Zr-bptc-50 wt%. Especially, the optimal composites showed high NH3/N2 IAST of 3146.21 for NH3/N2 (0.5/99.5, v/v) and 593.97 for NH3/N2 (5/95, v/v), which is 269 % and 346 % higher than that of pristine Zr-bptc, respectively, indicating the composites have great potential for low-concentration NH3 separation. Moreover, the mixed gas breakthrough experiments demonstrated that optimal DFIL@Zr-bptc also exhibits outstanding NH3/N2 separation performance under simulative conditions including ammonia synthesis process and air purification. In addition, the DFIL@Zr-bptc composites show great structural stability and recyclability. This work provides a feasible way to design novel porous IL composites for NH3 efficient removal and recovery.

Supported ionic liquids to purify microbial L-Asparaginase

L-Asparaginase (ASNase) is a versatile enzyme that converts L-asparagine into ammonia and aspartic acid. This enzyme has applications in the food industry and health sector. However, high purity ASNase is required, resulting in high production costs. Therefore, in this work, two supported ionic liquids (SILs), specifically silica modified with dimethylbutylpropylammonium chloride ([Si][N3114]Cl) or triethylpropylammonium chloride ([Si][N3222]Cl), were investigated as alternative adsorption materials to purify ASNase. Different conditions were evaluated to improve enzyme purity, including total protein content in the cell extract, contact time, and SIL/cell extract ratio (w/v). Under optimal conditions using [Si][N3114]Cl, a maximum ASNase purification of 6.1-fold is achieved in a single step, resulting from the preferential attachment of other proteins on [Si][N3114]Cl SIL. According to the results, hydrophobic interactions rule the selective adsorption of protein impurities from the cell extract by the SIL, thereby increasing the ASNase purification levels. This approach offers a significant advantage, not requiring the desorption and elution of the target enzyme, while envisioning the application of SILs in a flow-through elution approach. The protonation state of protein surface was calculated by computational analysis, revealing that positively charged amino acids such as arginine and lysine block the effective binding of the enzyme to the SILs. Overall, if properly designed, SILs are promising alternative supports for the downstream processing of ASNase from cell extracts.

Competitive Adsorptive Mechanism of H2/N2 in LTA/FAU Zeolites by Molecular Simulations and Experiments.

For industrial tail gas to be converted into high-purity hydrogen, the H2-N2 mixture needs to be separated efficiently. This work examined the adsorption characteristics and competitive mechanisms of H2 and N2 on LTA- and FAU-type zeolites, at 77 K, 298 K, and 0.1-10 bar by thoroughly analyzing results of adsorption capacity experiments and molecular simulations. In the Grand Canonical Monte Carlo (GCMC) simulations, the force field causing a molecular dipole of H2 and the polarization force field of N2 are first applied. The accuracy of the force field was experimentally verified. The findings indicate that N2 and H2 loading on Ca-FAU (Ca-LTA) are higher than Na-FAU (Na-LTA). On NaX at 77 K, the highest adsorption selectivity (N2/H2) is observed; on NaA at 298 K, it is the opposite. The GCMC data findings demonstrate that H2 and N2 have remarkably similar adsorption sites, with framework oxygen atoms and non-framework cations serving as the main adsorption sites for adsorbate molecules. Furthermore, the rate at which H2 diffuses is higher than that of N2. The study of redistribution charge before and after adsorption demonstrated that N2 has a greater affinity for the framework oxygen atoms than H2. This study provides a molecular theoretical foundation for the adsorption behavior of H2-N2 mixture in zeolites.

MOF-525 and Fe-loaded MOF-525 for the selective adsorption removal of Cu(Ⅱ) and Cr(VI)

Two Zr-MOFs (including MOF-525 and MOF-525(Fe)) are synthesized and used to evaluate the adsorption performances for Cu(Ⅱ) and Cr(VI). Batch experiments demonstrate MOF-525 exhibits excellent adsorption removal for Cu(Ⅱ) and MOF-525(Fe) shows excellent adsorption removal for Cr(VI). The isotherms characteristic results indicate MOF-525 is micropores and conformed to type I, while MOF-525(Fe) is mesopores and conformed to type Ⅳ. The removal efficiency of Cu(Ⅱ) by MOF-525 is sharply increased from 26.1 % to 99.7 % and that of Cr(VI) by MOF-525(Fe) is decreased slightly from 99.6 % to 95.5 % as the pH increased from 3.0 to 8.0; besides, the adsorption capacity of Cu(Ⅱ) is enhanced in the presence of Cl− or PO43−, but that of Cr(VI) is significantly decreased. The adsorption processes of both MOF-525 for Cu(II) and MOF-525(Fe) for Cr(VI) are fitted better to the pseudo-second-order kinetic model and Langmuir model, indicating they are mainly monolayer chemisorption. In addition, adsorption thermodynamics results demonstrate the adsorption processes are endothermic and spontaneous physisorption. The adsorption mechanisms investigations further revealing that the electrostatic interaction, reducing action, and coordination interaction are involved in the adsorption removal of Cu(II) and Cr(VI); moreover, the surface precipitation is existed in the adsorption of Cu(II) and the hydrogen bonding is found in that of Cr(VI).

Development of SERS Active Nanoprobe for Selective Adsorption and Detection of Alzheimer's Disease Biomarkers Based on Molecular Docking.

Development of SERS-based Raman nanoprobes can detect the misfolding of Amyloid beta (Aβ) 42 peptides, making them a viable diagnostic technique for Alzheimer's disease (AD). The detection and imaging of amyloid peptides and fibrils are expected to help in the early identification of AD. Here, we propose a fast, easy-to-use, and simple scheme based on the selective adsorption of Aβ42 molecules on SERS active gold nanoprobe (RB-AuNPs) of diameter 29 ± 3 nm for Detection of Alzheimer's Disease Biomarkers. Binding with the peptides results in a spectrum shift, which correlates with the target peptide. We also demonstrated the possibility of using silver nanoparticles (AgNPs) as precursors for the preparation of a SERS active nanoprobe with carbocyanine (CC) dye and AgNPs known as silver nanoprobe (CC-AgNPs) of diameter 25 ± 4 nm. RB-AuNPs probe binding with the peptides results in a spectrum shift, which correlates with the target peptide. Arginine peak appears after the conjugation confirms the binding of Aβ 42 with the nanoprobe. Tyrosine peaks appear after conjugated Aβ42 with CC-AgNPs providing binding of the peptide with the probe. The nanoprobe produced a strong, stable SERS signal. Further molecular docking was utilized to analyse the interaction and propose a structural hypothesis for the process of binding the nanoprobe to Aβ42 and Tau protein. This peptide-probe interaction provides a general enhancement factor and the molecular structure of the misfolded peptides. Secondary structural information may be obtained at the molecular level for specific residues owing to isotope shifts in the Raman spectra. Conjugation of the nanoprobe with Aβ42 selectively detected AD in bodily fluids. The proposed nanoprobes can be easily applied to the detection of Aβ plaques in blood, saliva, and sweat samples.

Role of catalyst oxidation states in the selective detection of reducing gases: A comparative study of nanocomposites based on Au and chemically/thermally reduced graphene oxide

Catalyst-loaded reduced graphene oxide (rGO) is a promising material for developing high-performance gas sensors. In this work, surface functionalization is achieved by loading different quantities of nanogold (Au) on chemically and thermally reduced graphene oxide (CRGO and TRGO). These materials showed selective gas response toward reducing gases such as hydrogen (H2), carbon monoxide (CO), and methane (CH4) in the temperature range RT to 150 °C. The quantity of Au catalysts and their oxidation states in the films influenced the selectivity attributes of the studied sensors. The surface oxidation states of the Au catalyst are different for CRGO-Au and TRGO-Au films. It is apparent from the results that the difference in the Au oxidation states is due to the variation in surface oxygen functionalities of the base matrix CRGO and TRGO. The experimental results are tallied with the proposed gas selectivity mechanism of CRGO-Au and TRGO-Au films.Novelty of the Work:In reduced graphene oxide based gas sensors, the combined influence of the graphene oxide reduction method, gold (Au) catalyst quantity, and valence oxidation states (in the Au catalyst) on the gas selectivity is rarely reported. The available reports only focus on examining the metallic gold (Au0) phase of the catalyst. However, it is necessary to note that Au can also exist in various higher oxidation states (Au+1, Au+2, Au+3, etc.), which provide selective gas adsorption sites. Therefore, this work addresses the above issue by employing chemically reduced graphene oxide (CRGO) and thermally reduced graphene oxide (TRGO) decorated with Au nanoparticles (Au wt% = 1 %, 50 % & 90 %) for the selective sensing of reducing gases.

Construction of quaternary ammonium nitroxy-hybrid magnetic mesoporous silica adsorbent system and its selective adsorption research of Re(Ⅶ)/Cu(Ⅱ)

This study focussed on the development of a quaternary ammonium nitroxy-hybrid magnetic mesoporous silica adsorption system (Fe3O4@MS-SiO2@3-CPTES@Tetra-N-ACE, Fe3O4@MS-SiO2@3-CPTES@Tetra-2N@ACE and Fe3O4@MS-SiO2@3-CPTES@Tetra-DE) was established with adsorption structures consisting of 1,4,7,10,13-pentaoxa-16-azacyclooctadecane (N-ACE), 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (2N-ACE) and a similar linear structure, 3,6-dioxy-1,8-octylenediamine (DE) for the selective separation of Re/Cu. The composites were characterized by Fourier transform Infrared spectroscopy(FT-IR), Energy dispersive spectrometer(EDS), X-ray Diffraction(XRD), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) measurements. The characterization of composites exhibits mesoporous and rich functional groups. The experimental results demonstrated that the Fe3O4@MS-SiO2@3-CPTES@Tetra-2N@ACE and Fe3O4@MS-SiO2@3-CPTES@Tetra-DE possessed superior adsorption capacities of Re(VII) in a wide acidic environment (pH=3–6). The maximum adsorption capacity of Fe3O4@MS-SiO2@3-CPTES@Tetra-2N@ACE and Fe3O4@MS-SiO2@3-CPTES@Tetra-DE were respectively up to 331.77 mg·g−1, 395.54 mg·g−1 at pH 5.0. Furthermore, the adsorption rate of these adsorbents was fast for only 2 h to absorb more than 80 % of Re(VII). Notably, when Fe3O4@MS-SiO2@3-CPTES@Tetra-2N@ACE and Fe3O4@MS-SiO2@3-CPTES@Tetra-DE were added into the rhenium copper binary solution with the concentration ratio from 1:1 and 1:50, the Re (Ⅶ) / Cu (Ⅱ) selectivity was constantly excellent (SelRe/Cu value > 1.46, SelRe/Cu max = 4.96). After 5 desorption processes for Re (Ⅶ) with 3 mol·L−1 NaCl and 1 mol·L−1 NaCl, respectively, the adsorption efficiency decreased by less than 10 % at Fe3O4@MS-SiO2@3-CPTES@Tetra-2N@ACE and Fe3O4@MS-SiO2@3-CPTES@Tetra-DE. The adsorption mechanism between the adsorbents and Re(VII) was mainly electrostatic interaction and ion exchange through TEM-EDS, FT-IR, and XPS. This novel adsorption system had a promising application in the selective separation of Re(VII)/Cu(Ⅱ).

Precisely constructed core-shell organic/inorganic heterojunction for heightened photoreduction of Cr(VI): Synergy of reinforced interface interaction and high-speed carrier transfer

Photocatalysis technology has been widely studied for treating Cr(VI) pollution in water and constructing heterogeneous structures presents a compelling approach to enhance the efficiency of Cr(VI) treatment. Pitifully, solely utilizing heterostructure, especially random composites of heterogeneous photocatalysts, often falls short of effectively enhancing the separation efficiency of photogenerated carriers. Furthermore, most photocatalysts interact weakly with the Cr(VI) anions, greatly reducing the utilization efficiency of photogenerated carriers. Herein, pyridine-based conjugated imprinted polymer (CIP) photocatalyst was precisely coated on urchin-like TiO2 using an in-situ condensation approach, forming a compact core–shell structure of organic/inorganic heterojunction. On the one hand, the compact heterojunction structure of the core–shell effectively improved the separation efficiency of photogenerated carriers. On the other hand, CIP enhanced the adsorption between the photocatalyst and Cr(VI), effectively improving the utilization efficiency of photogenerated carriers. Due to the collaborative effects of selective adsorption and core–shell heterojunction photocatalysis, the photocatalyst demonstrated remarkable performance in eliminating Cr(VI). For high concentration Cr(VI) pollution of 100 ppm, complete elimination could be achieved within 90 min. This research presented an innovative and efficient approach for the precise synthesis of photocatalysts.

Efficient adsorption of cationic dyes by a novel honeycomb-like porous hydrogel with ultrahigh mechanical property

The optimization of hydrogel structure is crucial for adsorption capacity, mechanical stability, and reusability. Herein, a chitosan and laponite-XLS co-doped poly(acrylic acid-co-acrylamide) hydrogel (CXAA) with honeycomb-like porous structures is synthesized by cooperative cross-linking of 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) and laponite-XLS in reticular frameworks of acrylic acid (AAc) and acrylamide (AM). The CXAA exhibits extraordinary mechanical performances including tough tensile strength (3.36 MPa) and elasticity (2756 %), which facilitates recycling in practical adsorption treatment and broadens potential applications. Since the regular porous structures can fully expose numerous adsorption sites and electronegative natures within polymer materials, CXAA displays efficient and selective adsorption properties for cationic dyes like methylene blue (MB) and malachite green (MG) from mixed pollutants and can reach record-high values (MB = 6886 mg g−1, MG = 11,381 mg g−1) compared with previously reported adsorbents. Therefore, CXAA exhibits promising potential for separating cationic and anionic dyes by their charge disparities. Mechanism studies show that the synergistic effects of HACC, laponite-XLS, and functional groups in monomers promote highly efficient adsorption. Besides, the adsorption capacity of CXAA remains stable even after undergoing five cycles of regeneration. The results confirm that CXAA is a promising adsorbent for effectively removing organic dyes in wastewater.

Combined experimental and theoretical studies on adsorption characteristics of graphitic carbon nitride for flue gas molecules

Graphitic carbon nitride (g-C3N4) is a novel selective adsorbent for separation of Hg0 and Hg2+, which plays a pivotal role in mercury continuous emission monitoring systems (Hg-CEMS). However, some of the flue gas components may interfere with their binding characteristics with g-C3N4. This study employs the density functional theory (DFT) and experimental method to investigate the adsorption behavior of gas components on g-C3N4 and elucidates the intrinsic driving forces behind these interactions and assesses their impact on separation of Hg0 and HgCl2. The binding energies of H2O, SO2, CO2, NO, and O2 molecules on g-C3N4 are −0.575 eV, −0.530 eV, −0.309 eV, −0.246 eV, and −0.238 eV, respectively. The electronic structure and weak interaction analyses indicate that these interactions are primarily van der Waals forces caused by multi-atomic interactions. In contrast, the binding energy between HCl and g-C3N4 is −0.557 eV, primarily controlled by weak H-N covalent bonds. The co-adsorption results indicate that flue gas molecules exert negligible effects on the binding of HgCl2 to g-C3N4 because the changes in binding energy are within 0.15 eV. The experimental results verify that under practical operating conditions, the adsorption of H2O, HCl, SO2, CO2, NO, and O2 on g-C3N4 is below 0.1 %, demonstrating those components do not interfere with the separation of Hg0 and HgCl2 by g-C3N4, nor do they affect the regeneration performance of g-C3N4. This study provides new insights into the development and practical application of separation and conversion modules in Hg-CEMS technologies.

Synthesis of bis(2-aminoethyl)amine functionalized mesoporous silica (SBA-15) adsorbent for selective adsorption of Pb2+ ions from wastewater.

Rapid growth in the industry has released large quantities of contaminants, particularly metal discharges into the environment. Heavy metal poisoning in water bodies has become a major problem due to its toxicity to living organisms. In this study, we developed a 3-chloropropyl triethoxysilane incorporated mesoporous silica nanoparticle (SBA-15) based adsorbent utilizing the sol-gel process and Pluronic 123 (P123) as a structure-directing surfactant. Furthermore, the produced SBA-15 NPs were functionalized with bis(2-aminoethyl)amine (BDA) using the surface grafting approach. The physical and chemical properties of the prepared SBA-15@BDA NPs were determined using a variety of instruments, including small-angle X-ray diffraction (SAXS), Fourier-transform infrared (FTIR), scanning electron microscope (SEM), N2 adsorption-desorption, thermogravimetric, particle size distribution, and zeta potential analysis. The MSN has a large surface area of up to 574m2/g, a pore volume of 0.57cm3/g, and a well-ordered mesoporous nanostructure with an average pore size of 3.6nm. The produced SBA-15@BDA NPs were used to adsorb selectively to lead (Pd2+) ions from an aqueous solution. The adsorption study was performed under various conditions, including the influence of solution pH, adsorbent dose, adsorption kinetics, adsorption selectivity in the presence of competing metal ions, and reusability. The results of the kinetic study demonstrated that SBA-15@BDA NPs absorb selectively Pb2+ ions via chemisorption. The SBA-15@BDA NPs show Pb2+ ions with a maximum adsorption capacity of ~ 88% and an adsorbed quantity of approximately ~ 112mg/g from the studied aqueous solution. The adsorption mechanism relies on coordination bonding between Pb2+ ions and surface-functionalized amine groups on SBA-15@BDA NPs. Furthermore, the proposed SBA-15@BDA NPs adsorbent demonstrated excellent reusability over five cycles without significantly reducing adsorption performance. As a consequence, SBA-15@BDA NPs might serve as an effective adsorbent for the selective removal of Pb2+ ions from aqueous effluent.

Leveraging porosity and morphology in hierarchically porous carbon microtubes for CO2 capture and separation from humid flue gases

Leveraging porosity, surface chemistry and morphology of porous carbons play a critical role in CO2 capture performance. However, the effective and sustainable synthesis of porous carbons with well-interconnected hierarchical pore structure, high-proportioned micropores and high yield remains a huge challenging by a mild one-step chemical activation without damaging the natural unique nanostructure. Here, we proposed a green and sustainable strategy to fabricate porous carbons with tailorable porosity and unique tubular structure by an inorganic dynamic porogen of CuCl2. The dynamic activation mechanism of CuCl2 was explored in detail. In particular, the hierarchical porosity with a high-proportioned narrow micropores can be finely tuned without sacrificing the natural tubular morphology. Importantly, the resultant porous carbon adsorbents have an excellent resistance to water vapor, which can capture CO2 from humid flue gases with satisfactory adsorption capacity and selectivity. The HPCM-3 can achieve the best CO2 uptakes of 4.05 and 2.05 mmol/g under 100 kPa at 25 and 50 °C, respectively. Such superior CO2 adsorption behaviors can be well maintained even at high humidity of 70 %, and hardly decay with the enhancement of humidity. This route provides a promising avenue for developing the practical trace CO2 carbon-based adsorbents on a large scale to sieve CO2 from humid flue gases.

Computer simulation‐guided template selection for a molecularly imprinted polymer for selective trifluralin adsorption

AbstractTo meet selective adsorption toward trifluralin, a novel molecularly imprinted polymer (MIP) was fabricated by the dummy template molecular imprinting technology. First, computational simulation was performed to select a suitable dummy template, 3,5‐dinitro‐4‐methylbenzoic acid (T1), based on the maximum basis set superposition error (BSSE)‐corrected binding interaction energy (ΔE) of the monomer N‐vinylpyrrolidone (NVP)‐T1 complex and its structural overlap with trifluralin. Then, the MIP was prepared via the bulk polymerization. The adsorption experiments showed the MIP exhibited a trifluralin adsorption capacity of 5.1 mg g−1, an imprinting factor (IF) of 2.2, and short adsorption equilibrium time of 5 min. The adsorption of trifluralin conformed to the Freundlich adsorption (R2 = 0.985) and pseudo‐second‐order model (R2 = 0.999). In addition, the MIP exhibited selectivity to trifluralin over other adsorbents, including structural analogs (pendimethalin and oryzalin), pesticide (carbendazim), and nitrocompounds (nitrofurantoin, furazolidone, and furaltadone), with the selectivity factor (β) in the range of 1.2–3.0, respectively. In trifluralin/oryzalin mixture, the IF toward oryzalin was still as high as 1.9. The removal rate of the MIP to trifluralin in environmental water samples ranged from 90.08% to 99.04%. This study provides theoretical and experimental insights for the preparation of MIP using dummy templates.

Pore engineering in highly stable hydrogen-bonded organic frameworks for efficient CH4 purification

The unsatisfactory stability of hydrogen-bonded organic frameworks (HOFs) arising from the weakness and flexibility of hydrogen-bonding (H-bonding) has generally hindered their practical applications. By synergistically employing three key strategies: (Ⅰ) introducing charge-assisted H-bonding to increase the polarity of the framework, (Ⅱ) optimizing the length of the building unit by extending the core structure of the linker molecule, and (III) incorporating functional sites containing methoxy and trifluoromethyl, to increase the stability of HOFs and the adsorption affinity for gas molecules, we successfully synthesized three charge-assisted hydrogen-bonded HOFs (NKM-HOF-3, NKM-HOF-4, and NKM-HOF-5; NKM = Nankai Materials). These HOFs exhibit distinct space configurations of nonporous packing, discrete cavities or continuous one-dimensional channels. Notably, NKM-HOF-5 exhibits commendable thermal and chemical stability and can be readily regenerated by re-solvothermal reaction. The activated NKM-HOF-5a exhibits a low affinity for CH4 but captures C2H6 and C3H8 with a relatively high affinity. According to theoretical calculations, the suitable pore size, together with functionalized and polarized surface environments in NKM-HOF-5a contribute to the excellent selective gas adsorption performance of NKM-HOF-5a. Furthermore, the dynamic breakthrough experiments demonstrate the highly efficient separation performance of NKM-HOF-5a for C2H6/CH4, C3H8/CH4, and C3H8/C2H6/CH4.

Self-supporting and hierarchical porous membrane of bacterial nanocellulose@metal-organic framework for ultra-high adsorption of Congo red

The widespread use of synthetic dyes has serious implications for both the environment and human health. Therefore, there is an urgent need for the development of novel, high-efficiency adsorbents for these dyes. In this study, a Zirconium-based metal-organic framework (MOF) with controllable morphology was in-situ grown on bacterial nanocellulose (BC) via a solvothermal method. The resulting BC@MOF composite nanofibers have a high specific surface area of 651 m2/g and can be assembled into a self-supported porous membrane (BMMCa) through vacuum filtration with the assistance of calcium ions. The addition of Ca(II) significantly enhanced the mechanical properties of the membrane through dispersion effect and electrostatic interactions, as well as enhancing its adsorption performance through the salting-out effect. The BMMCa membrane, with its hierarchical porous structure and high flux, exhibits high selectivity for Congo red (CR) with an ultra-high adsorption capacity of 3518.6 mg/g. Furthermore, the self-supporting membrane achieved rapid and convenient removal of CR through circulating filtration adsorption. The adsorption mechanism and selectivity were verified through the molecular dynamics simulation calculations by Materials Studio (MS) software. This membrane-based adsorbent, with its ultra-high adsorption capacity, good selectivity, and recycling ability, has great potential for practical wastewater treatment applications.

Highly porous P(DVB-AMPS) copolymer with tailored surface engineering for efficient fluoride capture from water

Surface engineering, especially surface hydrophilicity and active binding sites are crucial for porous polymers in the removal of fluoride ions from water. Herein, a novel P(DVB-AMPS) copolymer with tailored surface engineering was designed through a one-step polymerization method by incorporating diethylene-benzene (DVB) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). AMPS endows abundant active binding sites and provides P(DVB-AMPS) with both hydrophilicity and affinity for fluoride ions, while the monomer DVB acting as a crosslinker, facilitating pore generating. The surface hydrophilicity of P(DVB-AMPS) could be easily tuned by increasing the amounts of AMPS with the contact angle decreased from 126° (PDVB) to 52°. Furthermore, P(DVB-AMPS) material maintains a large specific surface area of 428 m2 · g[Formula: see text] and preserves its highly porous structure. P(DVB-AMPS) exhibits an efficient adsorption capacity (51.9 mg · g[Formula: see text]) and a rapid adsorption rate (6.83 mg · g[Formula: see text] · min[Formula: see text]), which demonstrates competitive performance compared with previous reports. Importantly, the material possesses highly selective adsorption toward fluoride. The excellent adsorption performance of P(DVB-AMPS) is attributed to the high porosity, improved surface hydrophilicity and active binding sites. This work not only provides a new strategy for designing high-performance adsorbents but also offers a novel polymer material for the efficient capture of fluoride ions from water.

Three Polyhedron-Based Metal-Organic Frameworks Exhibiting Excellent Acetylene Selective Adsorption.

The separation of acetylene (C2H2) from ethylene (C2H4) and ethane (C2H6) is crucial for the production of high-purity C2H2 and the recovery of other gases. Polyhedron-based metal-organic frameworks (PMOFs) are characterized by their spacious cavities, which facilitate gas trapping, and cage windows with varying sizes that enable gas screening. In this study, we carefully selected a class of PMOFs based on V-type tetracarboxylic acid linker (JLU-Liu22 containing benzene ring, JLU-Liu46 containing urea group and recombinant reconstructed In/Cu CBDA on the basis of JLU-Liu46) to study the relationship between pore environment and C2 adsorption and separation performance. Among the three compounds, JLU-Liu46 exhibits superior selectivity toward C2H2/C2H4 (2.06) as well as C2H2/C2H6 (2.43). Comparative structural analysis reveals that the exceptional adsorbed-C2H2 performance of JLU-Liu46 can be attributed to the synergistic effects arising from coordinatively unsaturated Cu sites combined with an optimal pore environment (matched pore size and polarity, urea functional group), resulting in a strong affinity between the framework and C2H2 molecules. Furthermore, transient breakthrough simulations of JLU-Liu46 confirmed its potential for separating C2H2 in ternary C2 gas.

Coffee-Ring Mediated Thinning and Thickness-Dependent Dewetting Modes in Printed Polymer Droplets Coupled with Assembly of Quantum Dots for Anti-Counterfeiting.

Molecular transport processes in printed polymer droplets hold enormous importance for understanding wetting phenomena and designing systems in applications such as encoding, electronics, photonics, and sensing. This paper studies thickness-dependent dewetting modes that are activated by thermal annealing and driven by interfacial interactions within microscopically confined polymeric features. The printing of poly(2-vinylpyridine) is performed in a regime where coffee-ring effects lead to strong thinning of the central region of the deposit. Thermal annealing leads to two different modes of dewetting that depend on the thickness of the central region. Mode I refers to the formation of randomly positioned small features surrounded by large hemispherical ones located along the periphery of the printed features and occurs when the central regions are thin. Observed at large central thicknesses, Mode II mediates significant molecular transport from edges toward the center of the printed droplet with thermal annealing and forms a hemispherical feature from the initial ring-like deposit. The selective adsorption of red, green, and blue emitting quantum dots over the poly(2-vinylpyridine) results in photoluminescent patterns. The selective assembly of photoluminescent quantum dots over patterned surfaces leads to deterministic and stochastic features beneficial to creating security labels for anti-counterfeiting applications.

Synthesis of an ion-imprinted starch phosphate porous carbonaceous material removing U(VI) from wastewater: Kinetics and mechanism

Uranium enrichment and separation are important for the sustainable development of nuclear energy. In this study, reverse-phase emulsion crosslinking polymerization was used to synthesize spherical hollow porous carbon materials (II-CLSPC) with a “red blood cell” morphology after roasting. The soft template method was used to modify II-CLSPC to obtain an open pore structure, which increased its contact area. Based on this, ion imprinting was conducted to improve the selective adsorption of U(VI). A spatial site matching the size of U(VI) was formed after ion template removal, which played a crucial role in this process. Multifaceted and multilevel improvements of II-CLSPC facilitated rapid adsorption, reaching equilibrium at 40 min and a removal rate of 94.6 % (pH 5, 298 K). The pseudo-second-order kinetic model and Langmuir isothermal model indicated that the adsorption process of uranyl ions by II-CLSPC involved via monolayer chemisorption with a theoretical saturation adsorption capacity of 653.6 mg g−1. In addition, II-CLSPC exhibited excellent selectivity (KdU = 3.7 × 104 mL g−1), cyclic stability, and salt tolerance, making it a promising candidate for uranium removal from wastewater.

Magnetic-driven metal–organic framework nanorobots for the coupling engineering of electronic waste treatment and environmental remediation

Gold recycling from secondary sources provides an economically viable and sustainable approach to meet the increasing global demand for this precious metal. However, gold resources are inherently scarce. To address this issue, the present study presents an innovative solution: dimercaptosuccinic acid functionalized magnetic metal–organic framework nanorobots (MNR-MOF-DMSA). These nanorobots are designed for swift, efficient, and selective capture of Au(III) trace amounts from complex aqueous mixtures. MNR-MOF-DMSA showed an ultra-high adsorption capacity, better selectivity, and reusability with long-term stability, as it can selectively extract over 94 % of Au(III) from complex e-waste leachate, and the adsorption capacity can reach 1716 mg/g (at pH 5 in 3 h) in harsh acidic condition followed Langmuir model. In addition, after conducting a detailed mechanistic analysis, it was discovered that the selective adsorption behaviors observed were due to the combined effect of several factors, including the reduction of sulfhydryl groups, the coordination interactions between amide groups and Au(III) ions, as well as the electrostatic interactions between protonated amino and AuCl4- ions. It is also worth mentioning that the better catalytic properties of the developed hybrid MOF (MNR-MOF-DMSA-Au) were due to the reduction of Au(III) to Au(0). This study proposes new ways to recover and reuse gold e-waste for a sustainable future, as well as environmental protection and remediation.