1
|
Remediation of Cd2+ in aqueous systems by alkali-modified (Ca) biochar and quantitative analysis of its mechanism. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.103750] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
2
|
Boguta P, Skic K, Sokołowska Z, Frąc M, Sas-Paszt L. Chemical Transformation of Humic Acid Molecules under the Influence of Mineral, Fungal and Bacterial Fertilization in the Context of the Agricultural Use of Degraded Soils. Molecules 2021; 26:molecules26164921. [PMID: 34443509 PMCID: PMC8399743 DOI: 10.3390/molecules26164921] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 11/16/2022] Open
Abstract
The main goal of this work was to study the structural transformation of humic acids (HAs) under the influence of selected strains of fungi (Aspergillus niger and Paecilomyces lilacinus) and bacteria (Bacillus sp., Paenibacillus polymyxa and Bacillus amyloliquefaciens) with/without the presence of NPK fertilizers. Two-year experiments were conducted on two different soils and HAs isolated from these soils were examined for structure, humification degree, and quantity using fluorescence and UV-Vis spectroscopy, elemental analysis, and extraction methods. Results showed that the applied additives contributed to the beneficial transformation of HAs, but effects differed for various soils. HAs from silty soil with higher organic carbon content showed simplification of their structure, and decreases in humification, molecular weight, and aromaticity under the influence of fungi and bacteria without NPK, and with NPK alone. With both fungi and NPK, increases in O/H and O/C atomic ratios indicated an increase in the number of O-containing functional groups. HAs from sandy soil did not show as many significant changes as did those from silty soil. Sandy soil exhibited a strong decline in HA content in the second year that was reduced/neutralized by the presence of fungi, bacteria, and NPK. Periodically observed fluorescence at ~300 nm/450 nm reflected formation of low-molecular HAs originating from the activity of microorganisms.
Collapse
Affiliation(s)
- Patrycja Boguta
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland; (K.S.); (Z.S.); (M.F.)
- Correspondence: ; Tel.: +48-817-445-061
| | - Kamil Skic
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland; (K.S.); (Z.S.); (M.F.)
| | - Zofia Sokołowska
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland; (K.S.); (Z.S.); (M.F.)
| | - Magdalena Frąc
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland; (K.S.); (Z.S.); (M.F.)
| | - Lidia Sas-Paszt
- Research Institute of Horticulture, Pomologiczna 18, 96-100 Skierniewice, Poland;
| |
Collapse
|
3
|
Novel Composite Materials for Lake Restoration: A New Approach Impacting on Ecology and Circular Economy. SUSTAINABILITY 2020. [DOI: 10.3390/su12083397] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The purpose of this study is to promote a new way of application composite materials to restore eutrophic waters. A new sustainable way of application is based on the “teabag” method, in which materials were placed in water-permeable bags and immersed in the water column in order to sorb phosphate—one of the main contributory element for the eutrophication problem. Particularly, the two composites materials of Phoslock™ (lanthanum-modified bentonite, LMB) and Bephos™ (Fe-modified bentonite, f-MB) were tested and bench-scale batch experiments were employed to investigate their sorption efficiency in the forms of slurry and teabag. The adsorption kinetics and the relevant adsorption isotherms were deployed, while the effect of the materials on turbidity and their aging were also investigated. Experimental results showed that Phoslock™ and Bephos™ (as teabag), being applied at initial concentration range: 0.05–5 mg/L, they sustained a maximum adsorption capacity of 7.80 mg/g and 25.1 mg/g, respectively, which are considered sufficient rates for P concentrations reported at natural aquatic ecosystems. At the same time this new method did not cause turbidity in the water column, since the material was not released into the water, thus, preventing potential harmful consequences for the living organisms. Moreover, the “teabag” method prevents the material to cover the lake bottom, avoiding the phenomenon of smothering of benthos. Βy teabag method, the materials can be collected for further applicability as soil improver or crops fertilizer. Finally, it was argued that the possibility to recycle LMB and f-MB materials for agricultural use is of paramount importance, sustaining also positive impacts on sustainable ecology and on the routes of circular economy (CE).
Collapse
|
4
|
Hu H, Li M, Wang G, Drosos M, Li Z, Hu Z, Xi B. Water-soluble mercury induced by organic amendments affected microbial community assemblage in mercury-polluted paddy soil. CHEMOSPHERE 2019; 236:124405. [PMID: 31545202 DOI: 10.1016/j.chemosphere.2019.124405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/17/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Mercury (Hg) pollution or organic amendments (OA) may individually induce changes in the microbial community of paddy soils. However, little is known regarding the interaction of Hg and OA and the effect of different OA applications on the microbial community assemblage in Hg-polluted paddy soil. A soil incubation experiment was performed by applying three organic amendments (OA), namely a food-waste compost (FC), and its HA and FA, into an Hg-polluted paddy soil to examine the changes in the microbial community and merA/merB gene abundance. The results showed that the OA treatments promoted total (SOC) and dissolved organic carbon (DOC) in soils, which may harbor copiotrophic bacteria. The HA and FA treatments decreased microbial diversity and richness along with an increase of water-soluble Hg (WHg) through the complexation of DOC to Hg, which may be mainly attributed to the enhanced Hg biotoxicity to soil microbiome induced by the increased WHg under these two treatments. Additionally, the WHg enhancement also contributed to the increase of Hg-resistant bacteria and merA/merB gene abundance, and consequently, induced changes in the microbial community. These results indicated the interaction of Hg and different OA induced the variation of WHg fraction in paddy soil, which played a fundamental role in the distinct responses of the microbial community assemblage. Collectively, the application of FA and HA to Hg-polluted soil should be limited considering Hg risk to microbiome, and FC can be an alternative.
Collapse
Affiliation(s)
- Hualing Hu
- College of Environmental Science and Engineering, Tianjin University, Tianjin, 300035, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Meng Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| | - Guoxi Wang
- Sino-Danish College, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Marios Drosos
- Institute of Resource, Ecosystem and Environment of Agriculture, Faculty of Biology and Environment, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Zhen Li
- Department of Soil Pollution and Control, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Zhengyi Hu
- Sino-Danish College, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Beidou Xi
- College of Environmental Science and Engineering, Tianjin University, Tianjin, 300035, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| |
Collapse
|
5
|
Ren D, Ren Z, Chen F, Wang B, Huang B. Predictive role of spectral slope ratio towards 17α-ethynylestradiol photodegradation sensitized by humic acids. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 254:112959. [PMID: 31377327 DOI: 10.1016/j.envpol.2019.112959] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Humic acids (HAs) have been shown to dominate the photodegradation of steroid estrogens in natural waters. Nevertheless, how the photosensitizing ability of HAs relates to their structural and optical characteristics remains largely unknown. In this study, 17α-ethynylestradiol (EE2) was selected as a model compound to study to what extent easily-measurable characteristics of HAs might be used to predict their photosensitization potency. HAs were extracted from sediments of two different sources, and then subjected to structural and optical properties characterization using elemental analyzer, UV-vis spectroscopy and fluorescence spectroscopy. Photochemical experiments show that the HAs from the two sources can effectively meditate EE2 photodegradation. Although with drastically different structural and optical properties, the photosensitizing ability of these HAs towards EE2 can be well described by simple linear regressions using a spectroscopic index, the spectral slope ratio (SR). This optical indicator is correlated with various physicochemical properties of HAs, including the molecular weight, lignin content, charge-transfer interaction potential, photobleaching extent and sources. No universal prediction model could be established for predicting EE2 photodegradation kinetics on the basis of SR, but in specific waters SR could be a powerful indictor for predicting the EE2 photodegradation sensitized by HAs.
Collapse
Affiliation(s)
- Dong Ren
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
| | - Zhaogang Ren
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
| | - Fang Chen
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
| | - Bin Wang
- School of Environment and Resource, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Bin Huang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China.
| |
Collapse
|
6
|
Li M, Drosos M, Hu H, He X, Wang G, Zhang H, Hu Z, Xi B. Organic amendments affect dissolved organic matter composition and mercury dissolution in pore waters of mercury-polluted paddy soil. CHEMOSPHERE 2019; 232:356-365. [PMID: 31158630 DOI: 10.1016/j.chemosphere.2019.05.234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/24/2019] [Accepted: 05/27/2019] [Indexed: 05/08/2023]
Abstract
Organic amendments (OA) have been applied in many mercury (Hg)-polluted paddy soils to meet increasing food demands with scarce land resources. However, little is known on the effects of different OAs on Hg dissolution and the composition of dissolved organic matter (DOM) in soil pore waters, both of which may be associated with Hg mobility. Consequently, DOM composition and Hg release levels were investigated in soil pore waters after applying food waste compost (FC), fulvic acids (FA) and humic acids (HA) to Hg-polluted paddy soils. FA and HA treatments promoted increased abundances of humic- and fulvic-like substances in pore water DOM while FC amendment increased soluble microbial by-products. FA amendment and high levels of both HA and FC amendments greatly promoted Hg dissolution in pore waters that could be attributed to the complexation of Hg with different DOM components. However, among all DOM components, only UVA fulvic and visible humic-like substances were positively correlated with Hg release levels and total organic carbon. These results indicate that discrepant DOM compositions are induced by different OA. Further, these differences may be associated with differential Hg dissolution in pore waters. Consequently, FA amendment and high level of FC or HA amendments should be limited to reduce potential Hg release into pore waters.
Collapse
Affiliation(s)
- Meng Li
- Key Laboratory of Environmental Criterial and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Marios Drosos
- Institute of Resource, Ecosystem and Environment of Agriculture, Faculty of Biology and Environment, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Hualing Hu
- Key Laboratory of Environmental Criterial and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; College of Environmental Sciences and Engineering, Tianjin University, Tianjin, 300350, China
| | - Xiaosong He
- Key Laboratory of Environmental Criterial and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Guoxi Wang
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hui Zhang
- Key Laboratory of Environmental Criterial and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Zhengyi Hu
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Beidou Xi
- Key Laboratory of Environmental Criterial and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| |
Collapse
|
7
|
Influence of crop rotation, tillage and fertilization on chemical and spectroscopic characteristics of humic acids. PLoS One 2019; 14:e0219099. [PMID: 31247049 PMCID: PMC6597113 DOI: 10.1371/journal.pone.0219099] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 06/16/2019] [Indexed: 11/20/2022] Open
Abstract
The changes in soil organic matter composition induced by anthropogenic factors is a topic of great interest for the soil scientists. The objective of this work was to identify possible structural changes in humic molecules caused by a 2-year rotation of durum wheat with faba bean, lasted for a decade, and conducted with different agricultural practices in a Mediterranean soil. Humic acids (HA) were extracted at three depths (0–30, 30–60 and 60–90 cm) from a Mediterranean soil subjected to different tillage (no tillage, minimum tillage and conventional tillage), crops (faba bean and wheat), and fertilization. The changes in HA quality were assessed by several chemical (ash, yield and elemental analysis) and spectroscopic techniques (solid-state 13C nuclear magnetic resonance, Fourier transform infrared and fluorescence). The results suggest that the different agronomic practices strongly affected the quality of HA. Smaller but more aromatic molecules were observed with depth, while the fertilization induced the formation of simpler and less aromatic molecules due to the enhanced decomposition processes. Under no tillage, more stable humic molecules were observed due to the less soil aeration, while under conventional tillage larger and more aromatic molecules were obtained. Compared to wheat, more aromatic and more oxidized but less complex molecules were observed after faba bean crop. The inorganic fertilization accelerates the decomposition of organic substances rather than their stabilization. At the end of each crop cycle, humic matter of different quality was isolated and this confirms the importance of the rotation practice to guarantee a diversification of the soil organic matter with time. Finally, no tillage induces the formation of more stable humic matter.
Collapse
|
8
|
Wang L, Li Y, Weng L, Sun Y, Ma J, Chen Y. Using chromatographic and spectroscopic parameters to characterize preference and kinetics in the adsorption of humic and fulvic acid to goethite. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 666:766-777. [PMID: 30812010 DOI: 10.1016/j.scitotenv.2019.02.235] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/09/2019] [Accepted: 02/15/2019] [Indexed: 05/20/2023]
Abstract
Humic substances (HS) are very heterogeneous, and preferential adsorption of certain components takes place during their interaction with minerals. Our results indicated that for fulvic acid (FA) the relatively large (3.6-18.2 kDa) particles were preferred in the adsorption to goethite, whereas for humic acid (HA) the intermediate sized (3.6-12.0 kDa) fractions were preferred. Correlations between molar mass (Mw) and specific UV absorption values (SUVA) with ratios of UV light absorbance (E2/E3, E4/E6) were observed. The adsorption did not change the relation between E2/E3 and Mw, E4/E6 and SUVA. The E2/E3 and E4/E6 can probably be used as indicators of molar mass and aromaticity of HS in studying the preferential adsorption. The adsorption of HA and FA to goethite was fast and reached a steady state in about 6 h. The intermediate sized HA particles (3.6-12.0 kDa) were adsorbed quickly, and part of them was subsequently replaced by somewhat larger particles (>50 kDa). For FA, preferential adsorption of relative large particles (3.6-18.2 kDa) took place quickly, and there was a limited substitution by particles with higher aromaticity. Without specifying the property especially the molar mass range of HS under study, confusion can arise from researches using different HS materials.
Collapse
Affiliation(s)
- Long Wang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Yongtao Li
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China; College of Natural Resources & Environment, South China Agricultural University, Guangzhou 510642, China
| | - Liping Weng
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China; Department of Soil Quality, Wageningen University, P.O. Box 47, 6700, AA, Wageningen, the Netherlands.
| | - Yang Sun
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Jie Ma
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Yali Chen
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| |
Collapse
|
9
|
Drosos M, Nebbioso A, Mazzei P, Vinci G, Spaccini R, Piccolo A. A molecular zoom into soil Humeome by a direct sequential chemical fractionation of soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 586:807-816. [PMID: 28214121 DOI: 10.1016/j.scitotenv.2017.02.059] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 05/26/2023]
Abstract
A Humeomics sequential chemical fractionation coupled to advanced analytical identification was applied directly to soil for the first time. Humeomics extracted ~235% more soil organic carbon (SOC) than by the total alkaline extraction traditionally employed to solubilise soil humic molecules (soil Humeome). Seven fractions of either hydro- or organo-soluble components and a final unextractable humic residue were separated from soil. These materials enabled an unprecedented structural identification of solubilised heterogeneous humic molecules by combining NMR, GC-MS, and ESI-Orbitrap-MS. Identified molecules and their relative abundance were used to build up structure-based van Krevelen plots to show the specific contribution of each fraction to SOC. The stepwise isolation of mostly hydrophobic and unsaturated molecules of progressive structural complexity suggests that humic suprastructures in soil are arranged in multi-molecular layers. These comprised molecules either hydrophobically adsorbed on soil aluminosilicate surfaces in less stable fractions, or covalently bound in amorphous organo-iron complexes in more recalcitrant fractions. Moreover, most lipid molecules of the soil Humeome appeared to derive from plant polyesters rather than bacterial metabolism. An advanced understanding of soil humic molecular composition by Humeomics may enable control of the bio-organic dynamics and reactivity in soil.
Collapse
Affiliation(s)
- Marios Drosos
- Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy.
| | - Antonio Nebbioso
- Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy.
| | - Pierluigi Mazzei
- Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy.
| | - Giovanni Vinci
- Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy.
| | - Riccardo Spaccini
- Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy.
| | - Alessandro Piccolo
- Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l'Ambiente, l'Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", via Università 100, 80055 Portici, Italy.
| |
Collapse
|
10
|
Uyguner-Demirel CS, Birben NC, Bekbolet M. Elucidation of background organic matter matrix effect on photocatalytic treatment of contaminants using TiO 2 : A review. Catal Today 2017. [DOI: 10.1016/j.cattod.2016.12.030] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
11
|
Cao X, Drosos M, Leenheer JA, Mao J. Secondary Structures in a Freeze-Dried Lignite Humic Acid Fraction Caused by Hydrogen-Bonding of Acidic Protons with Aromatic Rings. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1663-1669. [PMID: 26836017 DOI: 10.1021/acs.est.5b02859] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A lignite humic acid (HA) was separated from inorganic and non-HA impurities (i.e., aluminosilicates, metals) and fractionated by a combination of dialysis and XAD-8 resin. Fractionation revealed a more homogeneous structure of lignite HA. New and more specific structural information on the main lignite HA fraction is obtained by solid-state nuclear magnetic resonance (NMR) spectroscopy. Quantitative (13)C multiple cross-polarization (multiCP) NMR indicated oxidized phenyl propane structures derived from lignin. MultiCP experiments, conducted on potassium HA salts titrated to pH 10 and pH 12, revealed shifts consistent with carboxylate and phenolate formation, but structural changes associated with enolate formation from aromatic beta keto acids were not detected. Two-dimensional (1)H-(13)C heteronuclear correlation (2D HETCOR) NMR indicated aryl-aliphatic ketones, aliphatic and aromatic carboxyl groups, phenol, and methoxy phenyl ethers. Acidic protons from carboxyl groups in both the lignite HA fraction and a synthetic HA-like polycondensate were found to be hydrogen-bonded with electron-rich aromatic rings. Our results coupled with published infrared spectra provide evidence for the preferential hydrogen bonding of acidic hydrogens with electron-rich aromatic rings rather than adjacent carbonyl groups. These hydrogen-bonding interactions likely result from stereochemical arrangements in primary structures and folding.
Collapse
Affiliation(s)
- Xiaoyan Cao
- Department of Chemistry and Biochemistry, Old Dominion University , 4541 Hampton Blvd, Norfolk, Virginia 23529, United States
| | - Marios Drosos
- Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare per l' Ambiente, l' Agroalimentare ed i Nuovi Materiali (CERMANU), Università di Napoli "Federico II", Via Università 100, 80055 Portici, Italy
| | - Jerry A Leenheer
- 4024 Douglas Mountain Drive, Golden, Colorado 80403, United States
| | - Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University , 4541 Hampton Blvd, Norfolk, Virginia 23529, United States
| |
Collapse
|