B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Yu
Han
,
Wenyuan
Huang
,
Meng
He
,
Bing
An
,
Yinlin
Chen
,
Xue
Han
,
Lan
An
,
Meredydd
Kippax-Jones
,
Jiangnan
Li
,
Yuhang
Yang
,
Mark D.
Frogley
,
Cheng
Li
,
Danielle
Crawshaw
,
Pascal
Manuel
,
Svemir
Rudic
,
Yongqiang
Chen
,
Ian
Silverwood
,
Luke L.
Daemen
,
Anibal J.
Ramirez-Cuesta
,
Sarah J.
Day
,
Stephen P.
Thompson
,
Ben F.
Spencer
,
Marek
Nikiel
,
Daniel
Lee
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[37155, 36474]
Open Access
Abstract: Capture of trace benzene is an important and challenging task. Metal–organic framework materials are promising sorbents for a variety of gases, but their limited capacity towards benzene at low concentration remains unresolved. Here we report the adsorption of trace benzene by decorating a structural defect in MIL-125-defect with single-atom metal centres to afford MIL-125-X (X = Mn, Fe, Co, Ni, Cu, Zn; MIL-125, Ti8O8(OH)4(BDC)6 where H2BDC is 1,4-benzenedicarboxylic acid). At 298 K, MIL-125-Zn exhibits a benzene uptake of 7.63 mmol g−1 at 1.2 mbar and 5.33 mmol g−1 at 0.12 mbar, and breakthrough experiments confirm the removal of trace benzene (from 5 to <0.5 ppm) from air (up to 111,000 min g−1 of metal–organic framework), even after exposure to moisture. The binding of benzene to the defect and open Zn(II) sites at low pressure has been visualized by diffraction, scattering and spectroscopy. This work highlights the importance of fine-tuning pore chemistry for designing adsorbents for the removal of air pollutants.
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Nov 2024
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[33049]
Open Access
Abstract: Increasing municipal solid waste (MSW) production poses challenges for sustainable urban development. Modern energy-from-waste (EfW) facilities incinerate MSW, reducing mass and recovering energy. In the UK, MSW incineration bottom ash (MSW IBA) is primarily reused in civil engineering applications. This study characterizes UK-produced MSW IBA, examining its pH-dependent leaching behaviour and response to environmental lixiviants. Results show predominant components include a melt phase, primary glass and fine ash aggregations, and a chemical composition dominated by SiO2 (30–50 %), CaO (∼15 %), Fe2O3 (∼10 %), and Al2O3 (∼8%). X-ray absorption near edge structure (XANES) analysis shows that Zn and Cu are most likely oxygen-bound (adsorbed to oxy-hydroxides and as oxides) with some sulphur bound. Polychlorinated biphenyls (PCBs) and polychlorinated dibenzodioxins/furans (PCDD/Fs) are well below regulatory limits, and polycyclic aromatic hydrocarbons (PAHs) were undetectable. Leaching tests indicate trace elements mobilize at pHs ≤ 6. With a natural pH of 11.3 and high buffering capacity, significant acid inputs to the MSW IBA are required to reach this pH, which are improbable in the environment. Wood chip additions increase leachate’s dissolved organic carbon (DOC) and reduce pH, but had minimal impact on metal-leaching behaviour. Synthetic plant exudate solutions minimally affect metal leaching at realistic concentrations, only enhancing leaching at ≥ 1500 mg l−1 DOC. This work supports MSW IBA’s low-risk in specified civil engineering applications.
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Oct 2024
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[11156, 16153]
Abstract: Metal finishing filter cake, Pb-Zn smelter slag and municipal waste combustion air pollution control residue (APCR) are hazardous industrial wastes from metal-finishing, smelting and municipal solid waste incineration. The speciation of toxic elements in these wastes controls their recovery or fate in the environment but has been little investigated. The doctoral research developed a step-by-step approach of using data from As, Cu, Cr, Ni and Zn K edge and Pb L3 edge X-ray Absorption Spectroscopy (XAS), supported by Ca, Fe, P, S and Si K-edge XAS and other techniques, to identify and compare element speciation in samples of the three types of waste. In the two investigated filter cakes (TX and ST), Cr and Fe co-precipitated as (CrxFe1-x)2O3∙yH2O. Ni was present as Ni(OH)2 and NiCO3·2Ni(OH)2·4H2O. Zn was present as poorly crystalline 2ZnCO3∙3Zn(OH)2 and Zn3(PO4)2. Pb was adsorbed on amorphous SiO2. Cu precipitated as Cu2Cl(OH)3, Cu(OH)2, and CuSO4·5H2O in ST, whereas Cu appeared to adsorb on amorphous SiO2 in TX which contained much less Pb. In Pb/Zn slag, arsenic speciation was likely dominated by arsenic (III) and (V) oxides and sulfide. Cu was mainly speciated as Cu2S, with some metallic Cu and a weathering product, Cu(OH)2. Pb was identified mainly in glass and apatite (e.g., Pb5(PO4)3OH). Zn was mainly present in glass, ZnS and possibly solid solutions with Fe oxides. In raw and water washed APCR, Cu was found mainly in Cu2Cl(OH)3 and CuO, followed by Cu in glass. Pb was identified mainly in glass, with some PbSO4 and a small portion of PbO. Zn was mainly present in Zn4Si2O7(OH)2∙H2O, 2ZnCO3∙3Zn(OH)2, and solid solutions with spinel Fe3O4. The application of XAS in the three wastes, following the step-by-step approach, significantly improved the understanding of speciation of the elements of interest at relatively low concentrations in a heterogeneous matrix, regardless of the crystallinity.
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Oct 2024
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B18-Core EXAFS
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Abstract: The increasing population and the global warming are motivating the transition from fossil fuel-based energy supply chain to a renewable sources-based one. Hydrogen production plays a major role in technologies for renewable energy. Urea oxidation reaction (UOR) has garnered significant attention in recent years as a promising and sustainable clean-energy technology. Urea-containing wastewater poses severe threats to the environment and human health. Numerous studies hence focus on developing UOR as a viable process for simultaneously remediating wastewater and produce hydrogen. Moreover, UOR, which has a thermodynamic potential of 0.37 V (Vs reversible hydrogen electrode, RHE), shows great promise in replacing the energy- intensive oxygen evolution reaction (OER, 1.23 Vs RHE). Since UOR entails a complex intermediate adsorption/desorption process, many studies are devoted to designing cost-effective and efficient catalysts. Notably, Nickel-based materials have demonstrated significant potential for the UOR process. In this thesis work, nickel hydroxide has been chosen as catalyst with the objective of preparing it from Ni-containing wastewater in the future in collaboration with Circular Materials s.r.l. In this thesis, however, the materials have been synthetized in the laboratory to better control their properties and be able to extract more consistent conclusions. Manganese (1.55) and molybdenum (2.16) have been selected as doping elements, considering their different electronegativity respect to nickel (1.91), and their effect on the UOR performance has been studied. Manganese is less expensive and more ecofriendly than the commonly used cobalt (1.88). Iron (1.83) is even cheaper than Mn but it was not selected since it is known that improves the OER but not the UOR. Molybdenum was selected for its high electronegativity since it was found that, in metal fluoride, the strong electronegativity of F makes the metal in the electron deficiency state, which can promote the high valence state of metal species and, therefore, promote urea oxidation. This materials were characterized with techniques such as, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray absorption (XAS) and X-ray photoelectron spectroscopy (XPS). They have been tested as UOR catalysts in alkaline solution. Nickel phosphide-based catalysts have been also obtained from the phosphorization of the nickel-based hydroxide materials. The nickel phosphide-based catalysts have been characterized using the same techniques previously mentioned. These materials have been then tested as HER and UOR catalysts. In general for all the materials, the presence of the second metal increased the activity. In UOR and OER measurements, Nickel phosphide-based samples reached higher current densities than the corresponding nickel hydroxide-based materials. For the nickel-hydroxide based-materials, the samples containing molybdenum showed a better performance during UOR than the ones containing manganese. While for the nickel-phosphide based materials it was the opposite. The foreign element did not have any effects on the activity towards the HER for the NiP-based samples. More negative on set values and low current densities were obtained.
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Oct 2024
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B22-Multimode InfraRed imaging And Microspectroscopy
I11-High Resolution Powder Diffraction
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Yu
Han
,
David
Brooks
,
Meng
He
,
Yinlin
Chen
,
Wenyuan
Huang
,
Boya
Tang
,
Bing
An
,
Xue
Han
,
Meredydd
Kippax-Jones
,
Mark D.
Frogley
,
Sarah J.
Day
,
Stephen P.
Thompson
,
Svemir
Rudic
,
Yongqiang
Chen
,
Luke L.
Daemen
,
Anibal J.
Ramirez-Cuesta
,
Catherine
Dejoie
,
Martin
Schroeder
,
Sihai
Yang
Diamond Proposal Number(s):
[33115, 30398]
Open Access
Abstract: The functionalization of metal–organic frameworks (MOFs) to enhance the adsorption of benzene at trace levels remains a significant challenge. Here, we report the exceptional adsorption of trace benzene in a series of zirconium-based MOFs functionalized with chloro groups. Notably, MFM-68-Cl2, constructed from an anthracene linker incorporating chloro groups, exhibits a remarkable benzene uptake of 4.62 mmol g–1 at 298 K and 0.12 mbar, superior to benchmark materials. In situ synchrotron X-ray diffraction, Fourier transform infrared microspectroscopy, and inelastic neutron scattering, coupled with density functional theory modeling, reveal the mechanism of binding of benzene in these materials. Overall, the excellent adsorption performance is promoted by an unprecedented cooperation between chloro-groups, the optimized pore size, aromatic functionality, and the flexibility of the linkers in response to benzene uptake in MFM-68-Cl2. This study represents the first example of enhanced adsorption of trace benzene promoted by −CH···Cl and Cl···π interactions in porous materials.
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Oct 2024
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Open Access
Abstract: Magnetised zeolite A, zeolite X and Na,K-CHA composites with superparamagnetic nanoparticles of SiO2-coated Fe3O4 or CoFe2O4 ferrite spinels were prepared, characterised and tested for ion exchange efficacy. They were synthesised by following three steps, synthesising Fe3O4 and CoFe2O4 nanoparticles by a solvothermal method, coating the metal oxide particles with SiO2 by a sol-gel process, and attaching the MxOy/SiO2 onto the zeolites during synthesis. The magnetic zeolites were characterised by X-ray diffraction, X-ray fluorescence spectroscopy, Raman spectroscopy, vibrating sample magnetometry and both scanning and transmission electron microscopy. It was confirmed they had superparamagnetic properties due to successful attachment of the MxOy/SiO2 particles onto the zeolites. Adsorption capacities of Sr2+ onto the magnetic zeolite A and zeolite X and Cs+ onto the magnetic Na,K-CHA were also evaluated. The results show the MxOy/SiO2 did not block the adsorption sites of the zeolites and the MxOy/SiO2 particles were not detached from the zeolites during the adsorption experiments.
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Sep 2024
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I19-Small Molecule Single Crystal Diffraction
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Paula
Escamilla
,
Marcello
Monteleone
,
Rita Maria
Percoco
,
Teresa F.
Mastropietro
,
Mariagiulia
Longo
,
Elisa
Esposito
,
Alessio
Fuoco
,
Johannes C.
Jansen
,
Rosangela
Elliani
,
Antonio
Tagarelli
,
Jesus
Ferrando-Soria
,
Valeria
Amendola
,
Emilio
Pardo
,
Donatella
Armentano
Diamond Proposal Number(s):
[28808]
Abstract: Heavy metal ions are a common source of water pollution. In this study, two novel membranes with biobased metal–organic frameworks (BioMOFs) embedded in a polyacrylonitrile matrix with tailored porosity were prepared via nonsolvent induced phase separation methods and designed to efficiently adsorb heavy metal ions from oligomineral water. Under optimized preparation conditions, stable membranes with high MOF loading up to 50 wt % and a cocontinuous sponge-like morphology and a high water permeability of 50–60 L m–2 h–1 bar–1 were obtained. The tortuous flow path in combination with a low water flow rate guarantees maximum contact time between the fluid and the MOFs, and thus a high heavy metal capture efficiency in a single pass. The performances of these BioMOF@PAN membranes were investigated in the dynamic regime for the simultaneous removal of Pb2+, Cd2+, and Hg2+ heavy metals from aqueous environments in the presence of common interfering ions. The new composite adsorbing membranes are capable of reducing the concentration of heavy metal pollutants in a single pass and at much higher efficiency than previously reported membranes. The enhanced performance of the mixed matrix membranes is attributed to the presence of multiple recognition sites which densely decorate the BioMOF channels: (i) the thioether groups, deriving from the S-methyl-l-cysteine and (S)-methionine amino acid residues, able to recognize and capture Pb2+ and Hg2+ ions and (ii) the oxygen atoms of the oxamate moieties, which preferentially interact with Cd2+ ions, as revealed by single crystal X-ray diffraction. The flexibility of the pore environments allows these sites to work synergically for the simultaneous capture of different metal ions. The stability of the membranes for a potential regeneration process, a key-factor for the effective feasibility of the process in real life applications, was also evaluated and confirmed less than 1% capacity loss in each cycle.
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Sep 2024
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Abstract: Mangroves provide fundamental ecosystem services; however, the growing impact of human activities has resulted in increased pollution pressure, such as chemical contaminants. The redox processes are major biogeochemical players in the fate of contaminants. We investigate the effects of the redox environment on As(V) and Cr(VI) adsorbed on goethite (i.e., Fe(III)-oxide) over 40 days of incubation in columns containing mangrove soil subjected to seawater saturation cycles. Our spectroscopic data highlighted a less Fe(III)-ordered arrangement on goethite over time; As(V) is strongly bound to goethite, which delayed until 20 days its remobilization and reduction to As(III). After 40 days, the goethite held ∼50% of the initial As, but it was 15% as As(III). On the other hand, Cr(VI) was desorbed almost completely in less than 10 days, and the residual Cr ions bound to goethite were almost totally converted to Cr(III). Our study stresses the importance of individual time-dependence in evaluating chemical speciation changes among potential toxic elements in wetland systems, such as mangroves and artificial wetlands designed to water treatment or soil remediation.
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Sep 2024
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I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[34409]
Open Access
Abstract: Per- and polyfluoroalkyl substances (PFAS) are emerging as bioaccumulative and toxic water pollutants, posing a large threat to human and aquatic organisms. This threat is aggravated by their extreme persistence to common degradation methods. Adsorption is regarded as the most conventional method to treat these contaminants, however, existing sorbents present considerable limitations on performance. The development of more efficient PFAS adsorbents is therefore of urgent need. The class of metal-organic frameworks (MOFs) can hold great promise for these purposes, featuring porous materials with high tailoring potential. Herein, a series of functionalized Zr-MOFs have been designed with boosted capacities for the adsorption of short- and long-chain perfluorinated carboxylic acids of environmental interest. The approach relies on chemistry-based concepts to introduce targeted post-synthetic modifications that promote PFAS···MOF interactions, specifically through coordinative bonding and hydrophobic effects. In particular, the framework TFA-MOF-808 (TFA = trifluoroacetic acid) displays the highest capture capacities reported for MOF materials in this pollutant class. Mechanistic studies, assisted by advanced synchrotron characterization techniques and theoretical calculations, support a ligand exchange process occurring during the adsorption phenomena. The results demonstrate the potential of this design approach in developing advanced PFAS sorbents with optimal performance.
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Aug 2024
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B18-Core EXAFS
E01-JEM ARM 200CF
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Diamond Proposal Number(s):
[23723, 17198]
Abstract: Electrochemical nitrate (NO3−) reduction reaction (NO3−RR) to ammonium (NH4+) or nitrogen (N2) provides a green route for nitrate remediation. However, nitrite generation and hydrogen evolution reactions hinder the feasibility of the process. Herein, dual single atom catalysts were rationally designed by introducing Ag/Bi/Mo atoms to atomically dispersed Nisingle bondNsingle bondC moieties supported by nitrogen-doped carbon nanosheet (NCNS) for the NO3−RR. Ni single atoms loaded on NCNS (Ni/NCNS) tend to reduce NO3− to valuable NH4+ with a high selectivity of 77.8 %. In contrast, the main product of NO3−RR catalyzing by NiAg/NCNS, NiBi/NCNS, and NiMo/NCNS was changed to N2, giving rise to N2 selectivity of 48.4, 47.1 and 47.5 %, respectively. Encouragingly, Ni/NCNS, NiBi/NCNS, and NiAg/NCNS showed excellent durability in acidic electrolytes, leading to nitrate conversion rates of 70.3, 91.1, and 93.2 % after a 10-h reaction. Simulated wastewater experiments showed that NiAg/NCNS could remove NO3− up to 97.8 % at −0.62 V after 9-h electrolysis. This work afforded a new strategy to regulate the reaction pathway and improve the conversion efficiency of the NO3−RR via engineering the dual atomic sites of the catalysts.
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Aug 2024
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