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Yang P, Bi Z, Shang Y, Chen K, Liang Y, Li X, Shang G. Bimodal AFM-Based Nanocharacterization of Cycling-Induced Topographic and Mechanical Evolutions of LiMn 2O 4 Cathode Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6406-6413. [PMID: 33999641 DOI: 10.1021/acs.langmuir.1c00325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Evolution of LiMn2O4 mechanical property during charge/discharge cycles is a critical issue because it is closely related to the performance of lithium-ion batteries. Extensive studies have been conducted by first-principles calculations/molecular dynamics simulation at the atomic level and by the nanoindentation technique at the micron scale. In this study, cycling-induced topographic and mechanical evolutions of the LiMn2O4 films are investigated at the nanoscale using the bimodal atomic force microscopy (AFM), which provides a complementary approach to bridge the gap between atomic-level calculation and micron-scale measurement. The topographic change and elastic modulus degradation of the LiMn2O4 films during the charge/discharge cycles are found to occur simultaneously and irreversibly. Moreover, a dramatic decrease in the elastic modulus of the films takes place at the first 10 cycles, which is consistent with the significant loss of the capacity and the change of the Coulombic efficiency measured by the galvanostatic method. By considering the nanoscale phenomena and the macroscopic measurement results, the reasons for the elastic modulus degradation are discussed. This study would be a valuable addition to a better understanding of the degradation mechanisms of this cathode material.
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Affiliation(s)
- Peifa Yang
- School of Physics, Beihang University, Beijing 100191, People's Republic of China
| | - Zhuanfang Bi
- School of Physics, Beihang University, Beijing 100191, People's Republic of China
| | - Yang Shang
- School of Physics, Beihang University, Beijing 100191, People's Republic of China
| | - Ke Chen
- School of Physics, Beihang University, Beijing 100191, People's Republic of China
| | - Yaowen Liang
- School of Physics, Beihang University, Beijing 100191, People's Republic of China
| | - Xiao Li
- School of Physics, Beihang University, Beijing 100191, People's Republic of China
| | - Guangyi Shang
- School of Physics, Beihang University, Beijing 100191, People's Republic of China
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Rashed Y, Messele SA, Zeng H, Gamal El-Din M. Mesoporous carbon xerogel material for the adsorption of model naphthenic acids: structure effect and kinetics modelling. ENVIRONMENTAL TECHNOLOGY 2020; 41:3534-3543. [PMID: 31046640 DOI: 10.1080/09593330.2019.1615130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
The study examined the preparation, characterization and the use of carbon xerogel (CX) material for the adsorption of three model naphthenic acids (NAs); such as, heptanoic acid (HPA), 5-cyclohexanepentanoic acid (CHPA), and 5-phenylvaleric acid (PVA). CX was synthesized by sol-gel method from resorcinol and formaldehyde. The characterization results showed that CX was a mesoporous material with large surface area (573 m2/g) and high pore volume (1.55 cm3/g), which was mainly composed of carbon (93.20%) and oxygen (6.71%). Adsorption studies revealed that PVA, the NA having an aromatic ring was adsorbed more easily by CX (87 mg/g) due to π-π interactions, followed by HPA (65 mg/g) and CHPA (61 mg/g). In addition, by studying the effect of solution pH, the result confirmed that repulsion greatly hindered the adsorption of HPA onto CX at pHs above that of the pHPZC and at lower pHs attractive electrostatic forces promoted adsorption. Adsorption kinetics fitted the pseudo-first-order model, which suggested that physisorption was most likely the means of adsorption. For the intraparticle diffusion model, the rate of film diffusion was higher than the rate of pore diffusion for each model compound regardless of their structure. Accordingly, this confirmed that pore diffusion was the rate-limiting step, although film diffusion still maintained a significant role in the rate of diffusion. In general, CX exhibited excellent adsorption performance due to its highly mesoporous character so it could be used as a passive treatment method in tailing ponds for removal of organic matters.
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Affiliation(s)
- Yara Rashed
- Department of Civil & Environmental Engineering, University of Alberta, Edmonton, Canada
| | | | - Hongbo Zeng
- Department of Chemical & Materials Engineering, University of Alberta, Edmonton, Canada
| | - Mohamed Gamal El-Din
- Department of Civil & Environmental Engineering, University of Alberta, Edmonton, Canada
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Moriguchi S, Tsujimoto T, Sasahara A, Kokawa R, Onishi H. Nanometer-Scale Distribution of a Lubricant Modifier on Iron Films: A Frequency-Modulation Atomic Force Microscopy Study Combined with a Friction Test. ACS OMEGA 2019; 4:17593-17599. [PMID: 31656935 PMCID: PMC6812132 DOI: 10.1021/acsomega.9b02821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Liquid lubricants used in mechanical applications are low-vapor-pressure hydrocarbons modified with a small quantity of polar compounds. The polar modifiers adsorbed on the surface of sliding solids dominate the friction properties when the sliding surfaces are in close proximity. However, a few methods are available for the characterization of the adsorbed modifiers of a nanometer-scale thickness. In this study, we applied frequency-modulation atomic force microscopy to evaluate the vertical and lateral density distributions of the adsorbed modifier in a real lubricant, namely, poly-α-olefin (PAO) modified with an orthophosphoric acid oleyl ester. The liquid-induced force on the probing tip was mapped on a plane that was perpendicular to the lubricant-iron interface with a force sensitivity on the order of 10 pN. The PAO in the absence of the ester modifier was directly exposed to the film, which produced a few liquid layers parallel to the film surface with layer-to-layer distances of 0.6-0.7 nm. A monomolecular layer of the modifier was intermittently adsorbed with increasing ester concentration in the bulk lubricant, with complete coverage seen at 20 ppm. The C18H35 chains of the oleyl esters fluctuating in the lubricant produced a repulsive force on the tip, which monotonically decayed with the tip-to-surface distance. The dynamic friction coefficient of sliding steel-lubricant-steel interfaces, which was separately determined using a friction tester, was compared with the force map determined on the iron film immersed in the corresponding lubricant. The complete monomolecular layer of the ester modifier on the static lubricant-iron boundary is a requirement for achieving smooth and stable friction at the sliding interface.
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Affiliation(s)
- Shiho Moriguchi
- Department
of Chemistry, School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
- Shimadzu
Techno-Research Incorporated, Nishinokyo-shimoaicho, Nakagyo-ku, Kyoto 604-8436, Japan
| | - Teppei Tsujimoto
- JXTG
Nippon Oil & Energy Corporation, Chidoricho, Naka-ku, Yokohama 231-0815, Japan
| | - Akira Sasahara
- Department
of Chemistry, School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
| | - Ryohei Kokawa
- Shimadzu
Corporation, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan
| | - Hiroshi Onishi
- Department
of Chemistry, School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
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Li M, Messele SA, Boluk Y, Gamal El-Din M. Isolated cellulose nanofibers for Cu (II) and Zn (II) removal: performance and mechanisms. Carbohydr Polym 2019; 221:231-241. [DOI: 10.1016/j.carbpol.2019.05.078] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/04/2019] [Accepted: 05/26/2019] [Indexed: 11/16/2022]
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Chen Z, Xiao X, Xing B, Chen B. pH-dependent sorption of sulfonamide antibiotics onto biochars: Sorption mechanisms and modeling. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 248:48-56. [PMID: 30771747 DOI: 10.1016/j.envpol.2019.01.087] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/08/2019] [Accepted: 01/19/2019] [Indexed: 06/09/2023]
Abstract
It remains a challenge to precisely predict and control environmental behaviors of ionizable organic contaminants (IOCs) due to their species change relative to pH and because of the lack of appropriate models to illustrate the underlying pH-dependent mechanisms. We studied the pH-dependent sorption behavior of five sulfonamide antibiotics (SAs) as typical IOCs with different pKa values towards a series of biochars as representative sorbents with well-characterized surface structures. After subtracting the contribution of the speciation effect using a classical speciation model, up to three unexpected enhanced sorption peaks could be found and regulated by the pKa,SA of the SAs and the pKa, BC of the biochars. The mono H-bond formation between the two pKa,SA of the SAs (pKa,SA1 is from NH2, pKa,SA2 is from SO2NH), and the biochar surface functional groups with comparable pKa values generated two peaks. Another peak around the middle between pKa,SA1 and pKa,SA2 appeared due to the aromatic π bonding-enhanced dual H-bond. All of these peaks were quantitatively separated by a novel two-compartment model, which was developed by capturing the characteristics of pH-dependent sorption. The quantified hydrogen bonding among different SAs elucidates the effectiveness and limits of the pKa equalization principle to predict the strengthening of hydrogen bonding at the solid-aqueous interface. This work recognizes the quantitative relationship among the structure, sorption, and H-bond interaction of biochars and guides the prediction of the fate of IOCs in the environment and the development of remediation options.
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Affiliation(s)
- Zaiming Chen
- Department of Environmental Engineering, Ningbo University, Ningbo, 315211, China; Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China
| | - Xin Xiao
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
| | - Baoliang Chen
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China.
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Pignatello JJ, Mitch WA, Xu W. Activity and Reactivity of Pyrogenic Carbonaceous Matter toward Organic Compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:8893-8908. [PMID: 28753285 DOI: 10.1021/acs.est.7b01088] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Pyrogenic carbonaceous matter (PCM) includes environmental black carbon (fossil fuel soot, biomass char), engineered carbons (biochar, activated carbon), and related materials like graphene and nanotubes. These materials contact organic pollutants due to their widespread presence in the environment or through their use in various engineering applications. This review covers recent advances in our understanding of adsorption and chemical reactions mediated by PCM and the links between these processes. It also covers adsorptive processes previously receiving little attention and ignored in models such as steric constraints, physicochemical effects of confinement in nanopores, π interactions of aromatic compounds with polyaromatic surfaces, and very strong hydrogen bonding of ionizable compounds with surface functional groups. Although previous research has regarded carbons merely as passive sorbents, recent studies show that PCM can promote chemical reactions of sorbed contaminants at ordinary temperature, including long-range electron conduction between molecules and between microbes and molecules, local redox reactions between molecules, and hydrolysis. PCM may itself contain redox-active functional groups that are capable of oxidizing or reducing organic compounds and of generating reactive oxygen species (ROS) from oxygen, peroxides, or ozone. Amorphous carbons contain persistent free radicals that may play a role in observed redox reactions and ROS generation. Reactions mediated by PCM can impact the biogeochemical fate of pollutants and lead to useful strategies for remediation.
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Affiliation(s)
- J J Pignatello
- Department of Environmental Sciences, The Connecticut Agricultural Experiment Station , New Haven, Connecticut 06504-1106, United States
| | - William A Mitch
- Department of Civil and Environmental Engineering, Stanford University , 473 Via Ortega, Stanford, California 94305, United States
| | - Wenqing Xu
- Department of Civil and Environmental Engineering, Villanova University , Villanova, Pennsylvania 19085, United States
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