1
|
Delcourte L, Berbon M, Rodriguez M, Subban K, Lends A, Grélard A, Morvan E, Habenstein B, Saupe SJ, Delhaes L, Aimanianda V, Daskalov A, Loquet A. Magic-angle spinning NMR spectral editing of polysaccharides in whole cells using the DREAM scheme. Methods 2024; 230:59-67. [PMID: 39047926 DOI: 10.1016/j.ymeth.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 07/27/2024] Open
Abstract
Most bacterial, plant and fungal cells possess at their surface a protective layer called the cell wall, conferring strength, plasticity and rigidity to withstand the osmotic pressure. This molecular barrier is crucial for pathogenic microorganisms, as it protects the cell from the local environment and often constitutes the first structural component encountered in the host-pathogen interaction. In pathogenic molds and yeasts, the cell wall constitutes the main target for the development of clinically-relevant antifungal drugs. In the past decade, solid-state NMR has emerged as a powerful analytical technique to investigate the molecular organization of microbial cell walls in the context of intact cells. 13C NMR chemical shift is an exquisite source of information to identify the polysaccharides present in the cell wall, and two-dimensional 13C-13C correlation experiments provide an efficient tool to rapidly access the polysaccharide composition in whole cells. Here we investigate the use of the adiabatic DREAM (for dipolar recoupling enhancement through amplitude modulation) recoupling scheme to improve solid-state NMR analysis of polysaccharides in intact cells. We demonstrate the advantages of two-dimensional 13C-13C experiments using the DREAM recoupling scheme. We report the spectral editing of polysaccharide signals by varying the radio-frequency carrier position. We provide practical considerations for the implementation of DREAM experiments to characterize polysaccharides in whole cells. We demonstrate the approach on intact fungal cells of Neurospora crassa and Aspergillus fumigatus, a model and a pathogenic filamentous fungus, respectively. The approach could be envisioned to efficiently reduce the spectral crowding of more complex cell surfaces, such as cell wall and peptidoglycan in bacteria.
Collapse
Affiliation(s)
- Loic Delcourte
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, Pessac, France
| | - Mélanie Berbon
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, Pessac, France
| | - Marion Rodriguez
- CNR des Aspergilloses Chroniques, Mycology-Parasitology Department, CHU Bordeaux, Bordeaux 33000, France
| | - Kamalraj Subban
- ImmunoConcEpT, CNRS, UMR 5164, University of Bordeaux, Bordeaux, France
| | - Alons Lends
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, Pessac, France
| | - Axelle Grélard
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, Pessac, France
| | - Estelle Morvan
- Univ. Bordeaux, CNRS, Inserm, IECB, UAR3033, US01, Pessac, France
| | - Birgit Habenstein
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, Pessac, France
| | - Sven J Saupe
- CNRS, Université de Bordeaux, IBGC, UMR 5095, Bordeaux, France
| | - Laurence Delhaes
- CNR des Aspergilloses Chroniques, Mycology-Parasitology Department, CHU Bordeaux, Bordeaux 33000, France; Centre de Recherche Cardio-Thoracique de Bordeaux, Inserm UMR 1045, Univ Bordeaux, Bordeaux 33000, France
| | - Vishukumar Aimanianda
- Institut Pasteur, Université Paris Cité, Immunobiology of Aspergillus, Mycology Department, Paris, France
| | - Asen Daskalov
- ImmunoConcEpT, CNRS, UMR 5164, University of Bordeaux, Bordeaux, France; State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
| | - Antoine Loquet
- Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, Pessac, France.
| |
Collapse
|
2
|
Gamage J, Voroney P, Gillespie A, Lo A, Longstaffe J. Evidence for the formation of fused aromatic ring structures in an organic soil profile in the early diagenesis. Sci Rep 2023; 13:12378. [PMID: 37524728 PMCID: PMC10390584 DOI: 10.1038/s41598-023-39181-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 07/20/2023] [Indexed: 08/02/2023] Open
Abstract
The presence of fused aromatic ring (FAR) structures in soil define the stability of the recalcitrant soil organic matter (RSOM). FAR are important skeletal features in RSOM that contribute to its extended residence time. During the early diagenesis, FAR structures are formed through condensation and polymerization of biomolecules produced during plant residue and microbial product decay. Molecular level characterization of the RSOM extracted from an organic soil profile gives important insights into the formation of FAR. Advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, including recoupled long-range C-H dipolar dephasing experiments on extracted humic acids (HA) showed that they contain diagenetically formed FAR different from charcoal and lignin. Peaks characteristic of FAR are observed at all depths in the soil profile, with a greater prevalence observed in the HA extracts from the clay soil layer at the bottom. In the clay soil layer, 78% of the aromatic carbon was non-protonated, and this was 2.2-fold higher than the topsoil. These data further strengthen our understanding of the humification process that could occur in early diagenesis and help explain the importance of incorporating diagenesis as an important phenomenon for long-term carbon sequestration in soil.
Collapse
Affiliation(s)
- Jeewan Gamage
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada.
| | - Paul Voroney
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Adam Gillespie
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Andy Lo
- Advanced Analysis Centre, NMR Centre, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - James Longstaffe
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| |
Collapse
|
3
|
Li Z, Jorn R, Samonte PRV, Mao J, Sivey JD, Pignatello JJ, Xu W. Surface-catalyzed hydrolysis by pyrogenic carbonaceous matter and model polymers: An experimental and computational study on functional group and pore characteristics. APPLIED CATALYSIS. B, ENVIRONMENTAL 2022; 319:121877. [PMID: 37846345 PMCID: PMC10578355 DOI: 10.1016/j.apcatb.2022.121877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
We employed a polymer network to understand what properties of pyrogenic carbonaceous matter (PCM; e.g., activated carbon) confer its reactivity, which we hereinafter referred to as PCM-like polymers (PLP). This approach allows us to delineate the role of functional groups and micropore characteristics using 2,4,6-trinitrotoluene (TNT) as a model contaminant. Six PLP were synthesized via cross-coupling chemistry with specific functionality (-OH, -NH2, -N(CH3)2, or -N ( CH 3 ) 3 + ) and pore characteristics (mesopore, micropore). Results suggest that PCM functionality catalyzed the reaction by: (1) serving as a weak base (-OH, -NH2) to attack TNT, or (2) accumulating OH- near PCM surfaces (-N ( CH 3 ) 3 + ). Additionally, TNT hydrolysis rates, pH and co-ion effects, and products were monitored. Microporous PLP accelerated TNT decay compared to its mesoporous counterpart, as further supported by molecular dynamics modeling results. We also demonstrated that quaternary ammonium-modified activated carbon enhanced TNT hydrolysis. These findings have broad implications for pollutant abatement and catalyst design.
Collapse
Affiliation(s)
- Zhao Li
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA
| | - Ryan Jorn
- Department of Chemistry, Villanova University, Villanova, PA 19085, USA
| | - Pamela Rose V. Samonte
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA
| | - Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA
| | - John D. Sivey
- Department of Chemistry, Towson University, Towson, MD 21252, USA
| | - Joseph J. Pignatello
- Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06511, USA
| | - Wenqing Xu
- Department of Civil and Environmental Engineering, Villanova University, Villanova, PA 19085, USA
| |
Collapse
|
4
|
Samonte PRV, Li Z, Mao J, Chaplin BP, Xu W. Pyrogenic carbon-promoted haloacetic acid decarboxylation to trihalomethanes in drinking water. WATER RESEARCH 2022; 210:117988. [PMID: 34959066 PMCID: PMC9195562 DOI: 10.1016/j.watres.2021.117988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Drinking water disinfection by chlorination or chloramination can result in the formation of disinfection byproducts (DBPs) such as haloacetic acids (HAAs) and trihalomethanes (THMs). Pyrogenic carbonaceous matter (PCM), such as activated carbon (AC), is commonly used as an ostensibly inert adsorbent to remove HAAs from water. HAA degradation has been mainly attributed to biological factors. This study, for the first time, revealed that abiotic HAA degradation in the presence of PCM could be important under water treatment conditions. Specifically, we observed complete destruction of Br3AA, a model HAA, in the presence of powder AC at pH 7 within 30 min. To understand the role of PCM and the reaction mechanism, we performed a systematic study using a suite of HAAs and various PCM types. We found that PCM significantly accelerated the transformation of three HAAs (Br3AA, BrCl2AA, Br2ClAA) at pH 7. Product characterization indicated an approximately 1:1 HAA molar transformation into their respective THMs following a decarboxylation pathway with PCM. The Br3AA activation energy (Ea) was measured by kinetic experiments at 15-45 °C with and without a model PCM, wherein a significant decrease in Ea from 25.7 ± 3.2 to 13.6 ± 2.2 kcal•mol-1 was observed. We further demonstrated that oxygenated functional groups on PCM (e.g., -COOH) can accelerate HAA decarboxylation using synthesized polymers to resemble PCM. Density functional theory simulations were performed to determine the enthalpy of activation (ΔH‡) for Br3AA decarboxylation with H3O+ and formic acid (HCOOH). The presence of HCOOH significantly lowered the overall ΔH‡ value for Br3AA decarboxylation, supporting the hypothesis that -COOH catalyzes the C-C bond breaking in Br3AA. Overall, our study demonstrated the importance of a previously overlooked abiotic reaction pathway, where HAAs can be quickly converted to THMs with PCM under water treatment relevant conditions. These findings have substantial implications for DBP mitigation in water quality control, particularly for potable water reuse or pre-chlorinated water that allow direct contact between HAAs and AC during filtration as well as PAC fines traveling with finished water in water distribution systems. As such, the volatilization and relative low toxicity of volatile THMs may be considered as a detoxification process to mitigate adverse DBP effects in drinking water, thereby lowering potential health risks to consumers.
Collapse
Affiliation(s)
- Pamela Rose V Samonte
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States
| | - Zhao Li
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States
| | - Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, United States
| | - Brian P Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago, 929 W. Taylor St., Chicago, IL 60607, United States; Institute of Environmental Science and Policy, University of Illinois at Chicago, 1603 W. Taylor St., Chicago, IL 60612, United States; Department of Civil, Materials, and Environmental Engineering, University of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607, United States
| | - Wenqing Xu
- Department of Civil and Environmental Engineering, Villanova University, 800 E. Lancaster Ave., Villanova, PA 19085, United States.
| |
Collapse
|
5
|
The Thermo-Oxidative Behavior of Cotton Coated with an Intumescent Flame Retardant Glycine-Derived Polyamidoamine: A Multi-Technique Study. Polymers (Basel) 2021; 13:polym13244382. [PMID: 34960933 PMCID: PMC8707849 DOI: 10.3390/polym13244382] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 11/25/2022] Open
Abstract
Linear polyamidoamines (PAAs) derived from the polyaddition of natural α-amino acids and N,N′-methylene bis(acrylamide) are intumescent flame retardants for cotton. Among them, the glycine-derived M-GLY extinguished the flame in horizontal flame spread tests at 4% by weight add-on. This paper reports on an extensive study aimed at understanding the molecular-level transformations of M-GLY-treated cotton upon heating in air at 300 °C, 350 °C and 420 °C. Thermogravimetric analysis (TGA) identified different thermal-oxidative decomposition stages and, coupled to Fourier transform infrared spectroscopy, allowed the volatile species released upon heating to be determined, revealing differences in the decomposition pattern of treated and untreated cotton. XPS analysis of the char residues of M-GLY-treated cotton revealed the formation of aromatic nanographitic char at lower temperature with respect to untreated cotton. Raman spectroscopy of the char residues provided indications on the degree of graphitization of treated and untreated cotton at the three reference temperatures. Solid state 13C nuclear magnetic resonance spectroscopy (NMR) provided information on the char structure as a function of the treatment temperature, clearly indicating that M-GLY favors the carbonization of cotton with the formation of more highly condensed aromatic structures.
Collapse
|
6
|
Rawal A, Che Man SH, Agarwal V, Yao Y, Thickett SC, Zetterlund PB. Structural Complexity of Graphene Oxide: The Kirigami Model. ACS APPLIED MATERIALS & INTERFACES 2021; 13:18255-18263. [PMID: 33797212 DOI: 10.1021/acsami.1c01157] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Investigation of highly oxidized graphene oxide (GO) by solid-state nuclear magnetic resonance (NMR) spectroscopy has revealed an exceptional level of hitherto undiscovered structural complexity. A number of chemical moieties were observed for the first time, such as terminal esters, furanic carbons, phenolic carbons, and three distinct aromatic and two distinct alkoxy carbon moieties. Quantitative one-dimensional (1D) and two-dimensional (2D) 13C{1H} NMR spectroscopy established the relative populations and connectivity of these different moieties to provide a consistent "local" chemical structure model. An inferred 2 nm GO sheet size from a very large (∼20%) edge carbon fraction by NMR analysis is at odds with the >20 nm sheet size determined from microscopy and dynamic light scattering. A proposed kirigami model where extensive internal cuts/tears in the basal plane provide the necessary edge sites is presented as a resolution to these divergent results. We expect this work to expand the fundamental understanding of this complex material and enable greater control of the GO structure.
Collapse
Affiliation(s)
- Aditya Rawal
- NMR Facility, Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Siti H Che Man
- Cluster for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Vipul Agarwal
- Cluster for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yin Yao
- Electron Microscopy Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Stuart C Thickett
- Cluster for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Per B Zetterlund
- Cluster for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| |
Collapse
|
7
|
Chen X, Ye X, Chu W, Olk DC, Cao X, Schmidt-Rohr K, Zhang L, Thompson ML, Mao J, Gao H. Formation of Char-Like, Fused-Ring Aromatic Structures from a Nonpyrogenic Pathway during Decomposition of Wheat Straw. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:2607-2614. [PMID: 32096642 DOI: 10.1021/acs.jafc.9b06037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fused-ring aromatics, important skeletal components of black carbon (BC), contribute to long-term carbon (C) sequestration in nature. They have previously been thought to be primarily formed by incomplete combustion of organic materials, whereas the nonpyrogenic origins are negligible. Using advanced solid-state 13C nuclear magnetic resonance (NMR), including recoupled long-range C-H dipolar dephasing, exchange with protonated and nonprotonated spectral editing (EXPANSE), and dipolar-dephased double-quantum/single-quantum (DQ/SQ) spectroscopy, we for the first time identify fused-ring aromatics that formed during the decomposition of wheat (Triticum sp.) straw in soil under aerobic, but not anaerobic conditions. The observed formation of polyaromatic units as plant litter decomposes provides direct evidence for humification. Moreover, the estimation of the annual flux of such nonpyrogenic BC could be equivalent to 3-12% of pyrogenic BC added to soils from all other sources. Our findings significantly extend the understanding of potential sources of fused-ring aromatic C and BC in soils as well as the global C cycle.
Collapse
Affiliation(s)
- Xi Chen
- Anhui Province Key Laboratory of Farmland Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Xinxin Ye
- Anhui Province Key Laboratory of Farmland Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Wenying Chu
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Daniel C Olk
- USDA-ARS, National Laboratory for Agriculture and the Environment, Ames, Iowa 50011, United States
| | - Xiaoyan Cao
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Ligan Zhang
- Anhui Province Key Laboratory of Farmland Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Michael L Thompson
- Agronomy Department, Iowa State University, Ames, Iowa 50011, United States
| | - Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Hongjian Gao
- Anhui Province Key Laboratory of Farmland Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| |
Collapse
|
8
|
Li Z, Mao J, Chu W, Xu W. Probing the Surface Reactivity of Pyrogenic Carbonaceous Material (PCM) through Synthesis of PCM-Like Conjugated Microporous Polymers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7673-7682. [PMID: 31244066 DOI: 10.1021/acs.est.9b01772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pyrogenic carbonaceous matter (PCM) is redox-active and promotes both abiotic and biotic reactions in the environment, possibly as a result of its conductivity and phenolic/quinone functional groups. However, due to the complexity of PCM, the contribution of conductivity or phenolic/quinone functional groups to its redox activity is poorly understood, which hinders its potential engineering applications. Here, we synthesized tunable conjugated microporous polymers (CMPs) that possess key properties of PCM, which can be used as PCM analogues to provide insights to PCM reactivity. Specifically, controlled incorporation of phenolic moieties into CMPs during polymer synthesis affected electron-donating capacity, while carbonization of CMPs at various temperatures altered conductivity. Both properties were then correlated with PCM reactivity measured by the decay kinetics of a model pollutant trichloronitromethane. We demonstrate that some of the prepared CMPs enabled transformation of trichloronitromethane, while no decay was observed in the absence of CMPs. Results of further investigation suggest that trichloronitromethane decay occurs by reductive dechlorination, suggesting that CMPs are electron donors and the first dissociative electron transfer from CMPs was likely to be the rate-limiting step. Conductivity but not electron-donating capacity was positively correlated with CMP-mediated trichloronitromethane decay kinetics, suggesting an important role of the electron transfer kinetics at the interface for PCM-mediated transformation of environmental pollutants.
Collapse
Affiliation(s)
- Zhao Li
- Department of Civil and Environmental Engineering , Villanova University , Villanova , Pennsylvania 19085 , United States
| | - Jingdong Mao
- Department of Chemistry and Biochemistry , Old Dominion University , Norfolk , Virginia 23529 , United States
| | - Wenying Chu
- Department of Chemistry and Biochemistry , Old Dominion University , Norfolk , Virginia 23529 , United States
| | - Wenqing Xu
- Department of Civil and Environmental Engineering , Villanova University , Villanova , Pennsylvania 19085 , United States
| |
Collapse
|
9
|
Hu S, Zhang D, Yang Y, Ran Y, Mao J, Chu W, Cao X. Effects of the Chemical Structure, Surface, and Micropore Properties of Activated and Oxidized Black Carbon on the Sorption and Desorption of Phenanthrene. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7683-7693. [PMID: 31244067 DOI: 10.1021/acs.est.9b01788] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The effects of the chemical structure, surface properties, and micropore of modified black carbon samples (BCs) on the sorption mechanism of hydrophobic organic contaminants (HOCs) are discussed. Activated and oxidized BCs were produced from a shale kerogen at 250-500 °C by chemical activation regents (KOH and ZnCl2) and then by oxidative regents (H2O2 and NaClO). The surface properties (water contact angel, Boehm titration, and cation exchange capacity, CEC), structural properties (advanced solid-state 13C NMR), micropore properties (CO2 adsorption), mesopore properties (N2 adsorption), and sorption and desorption properties of phenanthrene were obtained. The results showed that ZnCl2-activated BCs had higher basic surface groups, CEC values, aromatic carbon contents, micropore volumes, and adsorption volumes but exhibited lower acidic surface groups than the KOH-activated BCs did. Micropore modeling and sorption irreversibility indicated that the micropore filling was the main sorption mechanism of phenanthrene. In addition, ZnCl2 activated and NaClO oxidized BCs showed a nice regression equation between adsorption volumes and micropore volumes (CO2- V0) as follows: Q0' = 0.495 V0 + 6.28( R2 = 0.98, p < 0.001). Moreover, the contents of nonprotonated aromatic carbon, micropore volumes, and micropore sizes are the critical factors to micropore filling mechanism of phenanthrene on BCs. The size of fused aromatic rings was estimated from the recoupled 1H-13C dipolar dephasing, and the BC structural models at temperatures ranging from 300 to 500 were proposed. This finding improves our understanding of the sorption mechanism of HOCs from the perspectives of chemical structure and micropore properties.
Collapse
Affiliation(s)
- Shujie Hu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou 510640 , China
- University of Chinese Academy of Science , Beijing 100049 , China
| | - Dainan Zhang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou 510640 , China
| | - Yu Yang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou 510640 , China
| | - Yong Ran
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou 510640 , China
| | - Jingdong Mao
- Department of Chemistry and Biochemistry , Old Dominion University , Norfolk , Virginia 23529 , United States
| | - Wenying Chu
- Department of Chemistry and Biochemistry , Old Dominion University , Norfolk , Virginia 23529 , United States
| | - Xiaoyan Cao
- Department of Chemistry , Brandeis University , Waltham , Massachusetts 02453 , United States
| |
Collapse
|
10
|
Agrawal V, Sharma S. Improved Kerogen Models for Determining Thermal Maturity and Hydrocarbon Potential of Shale. Sci Rep 2018; 8:17465. [PMID: 30504862 PMCID: PMC6269451 DOI: 10.1038/s41598-018-35560-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 11/07/2018] [Indexed: 11/09/2022] Open
Abstract
Kerogen is the insoluble component of organic-rich shales that controls the type and amount of hydrocarbons generated in conventional and unconventional reservoirs. Significant progress has recently been made in developing structural models of kerogen. However, there is still a large gap in understanding the evolution of the molecular components of kerogen with thermal maturation and their hydrocarbon (HC) generative potential. Here, we determine the variations in different molecular fragments of kerogen from a Marcellus Shale maturity series (with VRo ranging from 0.8 to 3) using quantitative 13C MultiCP/MAS NMR and MultiCP NMR/DD (dipolar dephasing). These molecular variations provide insight into the (1) evolution of the molecular structure of kerogen with increasing thermal maturity and, (2) the primary molecular contributors to HC generation. Our results also indicate that old model equations based on structural parameters of kerogen underestimate the thermal maturity and overestimate the HC generation potential of Marcellus Shale samples. This could primarily be due to the fact that the kerogen samples used to reconstruct old models were mostly derived from immature shales (VRo <1) acquired from different basins with varying depositional environments. We utilized the kerogen molecular parameters determined from the Marcellus maturity series samples to develop improved models for determining thermal maturity and HC potential of Marcellus Shale. The models generated in this study could also potentially be applied to other shales of similar maturity range and paleo-depositional environments.
Collapse
Affiliation(s)
- Vikas Agrawal
- Department of Geology and Geography, West Virginia University, Morgantown, WV, United States
| | - Shikha Sharma
- Department of Geology and Geography, West Virginia University, Morgantown, WV, United States.
| |
Collapse
|
11
|
Clapp CE, Hayes MHB, Simpson AJ, Kingery WL. Chemistry of Soil Organic Matter. SSSA BOOK SERIES 2018. [DOI: 10.2136/sssabookser8.c1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- C. E. Clapp
- USDA-ARS, University of Minnesota; St. Paul Minnesota USA
| | | | | | - W. L. Kingery
- Mississippi State University; Mississippi State Mississippi USA
| |
Collapse
|
12
|
Huo J, Duan P, Pham HN, Chan YJ, Datye AK, Schmidt-Rohr K, Shanks BH. Improved hydrothermal stability of Pd nanoparticles on nitrogen-doped carbon supports. Catal Sci Technol 2018. [DOI: 10.1039/c8cy00947c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Carbon supports have been shown to provide better hydrothermal stability than alumina or silica supports, thus attracting more attention for aqueous-phase biomass conversion reactions.
Collapse
Affiliation(s)
- Jiajie Huo
- Department of Chemical and Biological Engineering
- Ames
- USA
- Center for Biorenewable Chemicals
- Iowa State University
| | - Pu Duan
- Center for Biorenewable Chemicals
- Iowa State University
- Ames
- USA
- Department of Chemistry
| | - Hien N. Pham
- Center for Biorenewable Chemicals
- Iowa State University
- Ames
- USA
- Department of Chemical and Biological Engineering and Center for Microengineered Materials
| | - Yee Jher Chan
- Department of Chemical and Biological Engineering
- Ames
- USA
| | - Abhaya K. Datye
- Center for Biorenewable Chemicals
- Iowa State University
- Ames
- USA
- Department of Chemical and Biological Engineering and Center for Microengineered Materials
| | - Klaus Schmidt-Rohr
- Center for Biorenewable Chemicals
- Iowa State University
- Ames
- USA
- Department of Chemistry
| | - Brent H. Shanks
- Department of Chemical and Biological Engineering
- Ames
- USA
- Center for Biorenewable Chemicals
- Iowa State University
| |
Collapse
|
13
|
Mao J, Cao X, Olk DC, Chu W, Schmidt-Rohr K. Advanced solid-state NMR spectroscopy of natural organic matter. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 100:17-51. [PMID: 28552171 DOI: 10.1016/j.pnmrs.2016.11.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/15/2016] [Accepted: 11/28/2016] [Indexed: 06/07/2023]
Abstract
Solid-state NMR is essential for the characterization of natural organic matter (NOM) and is gaining importance in geosciences and environmental sciences. This review is intended to highlight advanced solid-state NMR techniques, especially a systematic approach to NOM characterization, and their applications to the study of NOM. We discuss some basics of how to acquire high-quality and quantitative solid-state 13C NMR spectra, and address some common technical mistakes that lead to unreliable spectra of NOM. The identification of specific functional groups in NOM, primarily based on 13C spectral-editing techniques, is described and the theoretical background of some recently-developed spectral-editing techniques is provided. Applications of solid-state NMR to investigating nitrogen (N) in NOM are described, focusing on limitations of the widely used 15N CP/MAS experiment and the potential of improved advanced NMR techniques for characterizing N forms in NOM. Then techniques used for identifying proximities, heterogeneities and domains are reviewed, and some examples provided. In addition, NMR techniques for studying segmental dynamics in NOM are reviewed. We also briefly discuss applications of solid-state NMR to NOM from various sources, including soil organic matter, aquatic organic matter, organic matter in atmospheric particulate matter, carbonaceous meteoritic organic matter, and fossil fuels. Finally, examples of NMR-based structural models and an outlook are provided.
Collapse
Affiliation(s)
- Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Blvd., Norfolk, VA 23529, United States.
| | - Xiaoyan Cao
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, United States.
| | - Dan C Olk
- National Laboratory for Agriculture and the Environment, 1015 N. University Blvd., Ames, IA 50011, United States.
| | - Wenying Chu
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Blvd., Norfolk, VA 23529, United States.
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, United States.
| |
Collapse
|
14
|
Park J, Hung I, Gan Z, Rojas OJ, Lim KH, Park S. Activated carbon from biochar: influence of its physicochemical properties on the sorption characteristics of phenanthrene. BIORESOURCE TECHNOLOGY 2013; 149:383-389. [PMID: 24128401 DOI: 10.1016/j.biortech.2013.09.085] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 05/27/2023]
Abstract
The relationship between physicochemical properties of biochar-based activated carbons and its adsorption was investigated using an aromatic model compound, phenanthrene. Solid-state (13)C NMR analysis indicated more condensed aromatic structures when pyrolysis temperature increased or after activation process induced. The increasing aromaticity and non-protonated carbon fraction of the activated biochar treated at 300°C amounted to 14.7% and 24.0%, respectively, compared to 7.4% and 4.4% for biochar treated at 700°C. The surface area and pore volume were reduced with the increase in pyrolysis temperature, but increased after activation. Surface characteristics correlated with the initial sorption rate and equilibrium concentration of phenanthrene, but not with the aromaticity. Solid-state (2)H NMR for phenanthrene-d10 saturated activated biochars, however, showed substantial difference in molecular mobility, which might be due to the high aromaticity of the activated biochars. Overall, these results provide an opportunity to manipulate the characteristics of biomass-based adsorbents based on the application needs.
Collapse
Affiliation(s)
- Junyeong Park
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695, United States
| | | | | | | | | | | |
Collapse
|
15
|
Cao X, Ro KS, Libra JA, Kammann CI, Lima I, Berge N, Li L, Li Y, Chen N, Yang J, Deng B, Mao J. Effects of biomass types and carbonization conditions on the chemical characteristics of hydrochars. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:9401-9411. [PMID: 24004410 DOI: 10.1021/jf402345k] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Effects of biomass types (bark mulch versus sugar beet pulp) and carbonization processing conditions (temperature, residence time, and phase of reaction medium) on the chemical characteristics of hydrochars were examined by elemental analysis, solid-state ¹³C NMR, and chemical and biochemical oxygen demand measurements. Bark hydrochars were more aromatic than sugar beet hydrochars produced under the same processing conditions. The presence of lignin in bark led to a much lower biochemical oxygen demand (BOD) of bark than sugar beet and increasing trends of BOD after carbonization. Compared with those prepared at 200 °C, 250 °C hydrochars were more aromatic and depleted of carbohydrates. Longer residence time (20 versus 3 h) at 250 °C resulted in the enrichment of nonprotonated aromatic carbons. Both bark and sugar beet pulp underwent deeper carbonization during water hydrothermal carbonization than during steam hydrothermal carbonization (200 °C, 3 h) in terms of more abundant aromatic C but less carbohydrate C in water hydrochars.
Collapse
Affiliation(s)
- Xiaoyan Cao
- Department of Chemistry, College of Sciences, Nanjing Agricultural University , Nanjing 210095, People's Republic of China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Mao K, Kennedy GJ, Althaus SM, Pruski M. Spectral editing in 13C solid-state NMR at high magnetic field using fast MAS and spin-echo dephasing. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 47-48:19-22. [PMID: 22951436 DOI: 10.1016/j.ssnmr.2012.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 06/01/2023]
Abstract
A simple method is proposed for separating NMR resonances from protonated and non-protonated aromatic carbons in solids under fast magic angle spinning (MAS). The approach uses a MAS-synchronized spin-echo to exploit the differences in rotational recoupling of the dipolar interactions while fully refocusing the isotropic chemical shifts. This strategy extends the relevant time scale of spin evolution to milliseconds and circumvents the limitation of the traditional dipolar dephasing method, which in fast rotating solids is disrupted by rotational refocusing. The proposed approach can be used for quantitative measurement of carbon aromaticities in complex solids with poorly resolved spectra, as demonstrated for model compounds.
Collapse
Affiliation(s)
- Kanmi Mao
- ExxonMobil Research and Engineering Co., 1545 Route 22E, Annandale, NJ 08801, USA.
| | | | | | | |
Collapse
|
17
|
Freitas J, Cunha A, Emmerich F. Solid-State Nuclear Magnetic Resonance (NMR) Methods Applied to the Study of Carbon Materials. ACTA ACUST UNITED AC 2012. [DOI: 10.1201/b12960-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
|
18
|
Mao JD, Johnson RL, Lehmann J, Olk DC, Neves EG, Thompson ML, Schmidt-Rohr K. Abundant and stable char residues in soils: implications for soil fertility and carbon sequestration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:9571-9576. [PMID: 22834642 DOI: 10.1021/es301107c] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Large-scale soil application of biochar may enhance soil fertility, increasing crop production for the growing human population, while also sequestering atmospheric carbon. But reaching these beneficial outcomes requires an understanding of the relationships among biochar's structure, stability, and contribution to soil fertility. Using quantitative (13)C nuclear magnetic resonance (NMR) spectroscopy, we show that Terra Preta soils (fertile anthropogenic dark earths in Amazonia that were enriched with char >800 years ago) consist predominantly of char residues composed of ~6 fused aromatic rings substituted by COO(-) groups that significantly increase the soils' cation-exchange capacity and thus the retention of plant nutrients. We also show that highly productive, grassland-derived soils in the U.S. (Mollisols) contain char (generated by presettlement fires) that is structurally comparable to char in the Terra Preta soils and much more abundant than previously thought (~40-50% of organic C). Our findings indicate that these oxidized char residues represent a particularly stable, abundant, and fertility-enhancing form of soil organic matter.
Collapse
Affiliation(s)
- J-D Mao
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States
| | | | | | | | | | | | | |
Collapse
|
19
|
Montina T, Hazendonk P, Wormald P, Iuga D. The refocused discrimination induced by variable amplitude minipulses (DIVAM) experiment — Improved domain selection in semicrystalline fluoropolymers by 19F solid state nuclear magnetic resonance spectroscopy. CAN J CHEM 2011. [DOI: 10.1139/v11-043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The discrimination induced by variable amplitude minipulses (DIVAM) filter can be tuned to select for signals from a particular domain, therefore it is possible to obtain signals specific to different domains using only one experiment. An early description of the DIVAM sequence, where the filter terminates with cross-polarization, explains this tune ability using a simple one-spin-relaxation model, thereby limiting the selection mechanism to incoherent processes. Recently, a more complete description of the selection behaviour was offered for the DIVAM filter, when it was directly applied to the observed nucleus (direct DIVAM), taking into account both the incoherent and coherent terms. Direct DIVAM experiments on poly(vinylidenefluoride) (PVDF) show significant phase distortions when large excitation angles were used. The signal from the amorphous domain is seen to nutate in a normal fashion with respect to the excitation angle, while those from the crystalline and defect units did not. The refocused DIVAM sequence is introduced to restore normal nutation for all signals. The selection behaviour is investigated using SIMPSON (simulation program for solid-state nuclear magnetic resonance (NMR) spectroscopy) simulations. These illustrate that the isotropic shift terms have been effectively removed and the dipolar term attenuated, such that the chemical shift anisotropy (CSA) leads to domain selection; however, in a different manner than seen in direct DIVAM. Therefore, this sequence provides a method to select on the basis of the CSA term in the presence of both strong dipolar couplings and a large range of isotropic shifts.
Collapse
Affiliation(s)
- Tony Montina
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Paul Hazendonk
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Philip Wormald
- School of Chemistry, University of St Andrews, Purdie Building, St Andrews, Scotland KY16 9ST, UK
| | - Dinu Iuga
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| |
Collapse
|
20
|
Simpson AJ, McNally DJ, Simpson MJ. NMR spectroscopy in environmental research: from molecular interactions to global processes. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 58:97-175. [PMID: 21397118 DOI: 10.1016/j.pnmrs.2010.09.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 09/17/2010] [Indexed: 05/30/2023]
Affiliation(s)
- André J Simpson
- Environmental NMR Center, Department of Chemistry, University of Toronto, Ontario, Canada.
| | | | | |
Collapse
|
21
|
Solid-State Nuclear Magnetic Resonance Spectroscopy: A Review of Modern Techniques and Applications for Inorganic Polymers. J Inorg Organomet Polym Mater 2010. [DOI: 10.1007/s10904-010-9358-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
22
|
Fang X, Mao J, Levin EM, Schmidt-Rohr K. Nonaromatic Core−Shell Structure of Nanodiamond from Solid-State NMR Spectroscopy. J Am Chem Soc 2009; 131:1426-35. [DOI: 10.1021/ja8054063] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- XiaoWen Fang
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - JingDong Mao
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - E. M. Levin
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| |
Collapse
|
23
|
Hazendonk P, Wormald P, Montina T. The Direct DIVAM Experiment: A Spin Dynamics Analysis. J Phys Chem A 2008; 112:6262-74. [DOI: 10.1021/jp711489d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul Hazendonk
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada, and School of Chemistry, University of St. Andrews, Purdie Building, St Andrews KY16 9ST, U.K
| | - Philip Wormald
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada, and School of Chemistry, University of St. Andrews, Purdie Building, St Andrews KY16 9ST, U.K
| | - Tony Montina
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada, and School of Chemistry, University of St. Andrews, Purdie Building, St Andrews KY16 9ST, U.K
| |
Collapse
|
24
|
Mao J, Ajakaiye A, Lan Y, Olk DC, Ceballos M, Zhang T, Fan MZ, Forsberg CW. Chemical structures of manure from conventional and phytase transgenic pigs investigated by advanced solid-state NMR spectroscopy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:2131-8. [PMID: 17973446 DOI: 10.1021/jf071588x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Nonpoint phosphorus (P) pollution from animal manure is becoming a serious global problem. The current solution for the swine industry includes the enzyme phytase as a component in oil meal and cereal grain-based swine diets. A long-term approach is the production of transgenic phytase pigs that express phytase in the salivary glands and secrete it in the saliva. This study provides a detailed comparison of chemical structures of manure from conventional pigs and transgenic pigs that express phytase under growing and finishing phases using new solid-state NMR techniques. Spectral editing techniques and quantitative NMR techniques were used to identify and quantify specific functional groups. Two-dimensional (1)H- (13)C heteronuclear correlation NMR was used to detect their connectivity. Manure from conventional and transgenic pigs had similar peptide, carbohydrate, and fatty acid components, while those from transgenic pigs contained more carbohydrates and fewer nonpolar alkyls. There was no consistent effect from diets with or without supplemental phosphate or growth stages.
Collapse
Affiliation(s)
- Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Boulevard, Norfolk, Virginia 23529, USA.
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Gadad P, Lei H, Nanny MA. Characterization of noncovalent interactions between 6-propionyl-2-dimethylaminonaphthalene (PRODAN) and dissolved fulvic and humic acids. WATER RESEARCH 2007; 41:4488-96. [PMID: 17632208 DOI: 10.1016/j.watres.2007.06.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Revised: 05/31/2007] [Accepted: 06/06/2007] [Indexed: 05/16/2023]
Abstract
Noncovalent interactions between the fluorescent probe 6-propionyl-2-dimethylaminonaphthalene (PRODAN) and dissolved Norman Landfill leachate fulvic acid, Suwannee River fulvic acid, Suwannee River humic acid, and Leonardite humic acid were examined as a function of pH, fulvic and humic acid (FA and HA) concentration, and solvent polarity using steady-state fluorescence spectroscopy. Static quenching processes, as indicated by linear Stern-Volmer plots and high K(d) values, were positively correlated with the % aromaticity of the FA and HAs, as well as with solution pH. Results illustrate that for FA molecules with relatively low % aromaticity values, solvophobic interactions between PRODAN and FA are the primary interaction mode. For HA molecules with higher % aromaticity, PRODAN engages in both solvophobic interactions and pi-pi interactions, in particular electron donor-acceptor interactions, via condensed aromatic, electron-accepting moieties inherent within HA molecules. Experiments modifying solvent polarity demonstrated that protonation of carboxylic acid functional groups at low pH ( approximately 4) increased the hydrophobicity of the dissolved FA and HA molecules, thereby enhancing noncovalent interactions with PRODAN through increased solvophobic forces.
Collapse
Affiliation(s)
- Praveen Gadad
- School of Civil Engineering and Environmental Science, College of Engineering, The University of Oklahoma, Norman 73019, USA
| | | | | |
Collapse
|
26
|
Schmidt-Rohr K, Rawal A, Fang XW. A new NMR method for determining the particle thickness in nanocomposites, using T2,H-selective X{1H} recoupling. J Chem Phys 2007; 126:054701. [PMID: 17302492 DOI: 10.1063/1.2429069] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A new nuclear magnetic resonance approach for characterizing the thickness of phosphate, silicate, carbonate, and other nanoparticles in organic-inorganic nanocomposites is presented. The particle thickness is probed using the strongly distant-dependent dipolar couplings between the abundant protons in the organic phase and X nuclei (31P, 29Si, 13C, 27Al, 23Na, etc.) in the inorganic phase. This approach requires pulse sequences with heteronuclear dephasing only by the polymer or surface protons that experience strong homonuclear interactions, but not by dispersed OH or water protons in the inorganic phase, which have long transverse relaxation times T2,H. This goal is achieved by heteronuclear recoupling with dephasing by strong homonuclear interactions of protons (HARDSHIP). The pulse sequence alternates heteronuclear recoupling for approximately 0.15 ms with periods of homonuclear dipolar dephasing that are flanked by canceling 90 degrees pulses. The heteronuclear evolution of the long-T2,H protons is refocused within two recoupling periods, so that 1H spin diffusion cannot significantly dephase these coherences. For the short-T2,H protons of a relatively immobile organic matrix, the heteronuclear dephasing rate depends simply on the heteronuclear second moment. Homonuclear interactions do not affect the dephasing, even though no homonuclear decoupling is applied, because long-range 1H-X dipolar couplings approximately commute with short-range 1H-1H couplings, and heteronuclear recoupling periods are relatively short. This is shown in a detailed analysis based on interaction representations. The algorithm for simulating the dephasing data is described. The new method is demonstrated on a clay-polymer nanocomposite, diamond nanocrystals with protonated surfaces, and the bioapatite-collagen nanocomposite in bone, as well as pure clay and hydroxyapatite. The diameters of the nanoparticles in these materials range between 1 and 5 nm. Simulations show that spherical particles of up to 10 nm diameter can be characterized quite easily.
Collapse
Affiliation(s)
- K Schmidt-Rohr
- Ames Laboratory, and Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
| | | | | |
Collapse
|
27
|
Christiansen SC, Hedin N, Epping JD, Janicke MT, del Amo Y, Demarest M, Brzezinski M, Chmelka BF. Sensitivity considerations in polarization transfer and filtering using dipole-dipole couplings: implications for biomineral systems. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2006; 29:170-82. [PMID: 16343862 DOI: 10.1016/j.ssnmr.2005.10.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2005] [Revised: 10/19/2005] [Indexed: 05/05/2023]
Abstract
The robustness and sensitivities of different polarization-transfer methods that exploit heteronuclear dipole-dipole couplings are compared for a series of heterogeneous solid systems, including polycrystalline tetrakis(trimethylsilyl)silane (TKS), adamantane, a physical mixture of doubly (13)C,(15)N-enriched and singly (13)C-enriched polycrystalline glycine, and a powder sample of siliceous marine diatoms, Thalossiosira pseudonana. The methods were analyzed according to their respective frequency-matching spectra or resultant signal intensities. For a series of (13)C{(1)H} cross-polarization experiments, adiabatic passage Hartmann-Hahn cross-polarization (APHH-CP) was shown to have several advantages over other methods, including Hartmann-Hahn cross-polarization (HHCP), variable-amplitude cross-polarization (VACP), and ramped-amplitude cross-polarization (RACP). For X-Y systems, such as (13)C{(15)N}, high and comparable sensitivities were obtained by using APHH-CP with Lee-Goldburg decoupling or by using the transferred-echo double resonance (TEDOR) experiment. The findings were applied to multinuclear (1)H, (13)C, (15)N, and (29)Si CP MAS characterization of a powder diatom sample, a challenging inorganic-organic hybrid solid that places high demands on NMR signal sensitivity.
Collapse
Affiliation(s)
- Sean C Christiansen
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Mao JD, Schmidt-Rohr K. Separation of aromatic-carbon 13C NMR signals from di-oxygenated alkyl bands by a chemical-shift-anisotropy filter. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2004; 26:36-45. [PMID: 15157537 DOI: 10.1016/j.ssnmr.2003.09.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Indexed: 05/24/2023]
Abstract
Selection of alkyl-carbon and suppression of aromatic-carbon 13C nuclear magnetic resonance (NMR) signals has been achieved by exploiting the symmetry-based, systematic difference in their 13C chemical-shift anisotropies (CSAs). Simple three- or five-pulse CSA-recoupling sequences with "gamma-integral" cleanly suppress the signals of all sp2- and sp-hybridized carbons. The chemical-shift-anisotropy-based dephasing is particularly useful for distinguishing the signals of di-oxygenated alkyl (O-C-O) carbons, found for instance as anomeric carbons in carbohydrates, from bands of aromatic carbons with similar 13C isotropic chemical shifts. The alkyl signals are detected with an efficiency of > 60%, with little differential dephasing. Combined with C-H dipolar dephasing, the CSA filter can identify ketal (unprotonated O-C-O) carbons unambiguously for the first time. Conversely, after short cross polarization and the CSA filter, O-CH-O (acetal) carbon signals are observed selectively. The methods are demonstrated on various model compounds and applied to a humic acid.
Collapse
Affiliation(s)
- J-D Mao
- Department of Chemistry, Iowa State University, Gilman Hall, Ames 50011, USA
| | | |
Collapse
|