Density functional theory prediction of p K a for carboxylated single-wall carbon nanotubes and graphene

Li, Hao; Fu, Aiping; Xue, Xu; Guo, Feng-Na; Huai, Wenbo; Chu, Tianshu; Wang, Zonghua

doi:10.1016/j.chemphys.2017.04.004

Cited by 10 publications

(13 citation statements)

References 48 publications

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“…The degree of protonation/deprotonation and hence the magnitude of sensor response strongly associate with the amplitude of pH change. Indeed, protonation or deprotonation has been suggested as the mechanism for shifting the Fermi level by electrostatic doping or charging of SWCNT–COOH, giving rise to electronic structure changes that have been previously observed as changes in optical absorbance (Figure b). ,, In addition, p K a values for SWCNT–COOH depicted in Figure b have been predicted theoretically . As mentioned in the introduction, our previous study reported a series of SWCNT–COOH sensors with varying pH levels and systematically cataloged responses to NH 3 and CO 2 , thus confirming experimentally and theoretically that exploring pH change is useful to understand SWCNT–COOH sensor responses .…”

Section: Resultssupporting

confidence: 78%

“…5,21,22 In addition, pK a values for SWCNT−COOH depicted in Figure 1b have been predicted theoretically. 23 As mentioned in the introduction, our previous study reported a series of SWCNT−COOH sensors with varying pH levels and systematically cataloged responses to NH 3 and CO 2 , thus confirming experimentally and theoretically that exploring pH change is useful to understand SWCNT−COOH sensor responses. 5 SWCNT sensors can maximize orthogonal responses to specific acidic or basic gas by adjusting the amount of additives.…”

Section: ■ Results and Discussionsupporting

confidence: 62%

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pH Modeling to Predict SWCNT–COOH Gas Sensor Response to Multiple Target Gases

et al. 2021

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Carboxylated single-walled carbon nanotubes (SWCNT−COOH) have long been studied for gas/vapor sensing. Controlling the pH during the carboxylation process by adding an acid or a base yields inks with different pH values, enabling an array of sensors that can give orthogonal responses to target gases and vapors. The gas detection mechanism for these sensors under prevailing humidity is via protonation or deprotonation of the carboxylate groups induced by pH changes. Here, we have developed a computational model, as a design tool, to control the pH and test various target acidic (CO 2 , H 2 S, HCl, and HF) and basic [NH 3 , CH 3 NH 2 , (CH 3 ) 2 NH, and (CH 3 ) 3 N] gases. The results confirm the utility of the model in decision-making on sensor design as well as to develop multiple sensor arrays for constructing an electronic nose with the aid of machine learning, in advance of actual fabrication.

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Section: Resultssupporting

confidence: 78%

Section: ■ Results and Discussionsupporting

confidence: 62%

pH Modeling to Predict SWCNT–COOH Gas Sensor Response to Multiple Target Gases

et al. 2021

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“…This PAC was chosen for analysis rather than a powderized form of the F-200 GAC to assess neonicotinoid sorption to a commercially available sorbent in use at the University of Iowa DWTP where we previously studied neonicotinoid removal from drinking water. , Non-functionalized multiwalled carbon nanotubes (CNTs, 190 m 2 g –1 ), carboxylic acid-functionalized, and amine-functionalized multiwalled CNTs were used in isotherm experiments to probe sorption mechanisms (Table S.1). Carboxylated CNTs (120 m 2 g –1 ) were chosen as an analog for activated carbon with predominantly negative surface charge at pH 7 based on reports of p K a values for surface carboxyl groups (p K a < 5) . Amine-functionalized CNTs (220 m 2 g –1 ) were chosen to compare effects of functional groups expected to have a more neutral charge in aqueous suspensions at pH 7 based on existing characterization and application in metal cation uptake .…”

Section: Methodsmentioning

confidence: 99%

Differences in Neonicotinoid and Metabolite Sorption to Activated Carbon Are Driven by Alterations to the Insecticidal Pharmacophore

Webb

Nagorzanski

Powers

et al. 2020

Environ. Sci. Technol.

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Widespread application of neonicotinoids has led to their proliferation in waters. Despite low neonicotinoid hydrophobicity, our prior studies implicated granular activated carbon (GAC) in neonicotinoid removal. Based on known receptor binding characteristics, we hypothesized that the insecticidal pharmacophore influences neonicotinoid sorption. Our objectives were to illuminate drivers of neonicotinoid sorption for parent neonicotinoids (imidacloprid, clothianidin, thiamethoxam, and thiacloprid) and pharmacophore-altered metabolites (desnitro-imidacloprid and imidacloprid urea) to GAC, powdered activated carbon, and carbon nanotubes (CNTs). Neonicotinoid sorption to GAC was extensive and largely irreversible, with significantly greater sorption of imidacloprid than desnitro-imidacloprid. Imidacloprid and imidacloprid urea (electronegative pharmacophores) sorbed most extensively to nonfunctionalized CNTs, whereas desnitro-imidacloprid (positive pharmacophore) sorbed most to COOH-CNTs, indicating the importance of charge interactions and/or hydrogen bonding between the pharmacophore and carbon surface. Water chemistry parameters (temperature, alkalinity, ionic strength, and humic acid) inhibited overall neonicotinoid sorption, suggesting that pharmacophore-driven sorption in real waters may be diminished. Analysis of a full-scale drinking water treatment plant GAC filter influent, effluent, and spent GAC attributes neonicotinoid/metabolite removal to GAC under real-world conditions for the first time. Our results demonstrate that the neonicotinoid pharmacophore not only confers insecticide selectivity but also impacts sorption behavior, leading to less effective removal of metabolites by GAC filters in water treatment.

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“…The pH of the mixture was adjusted to pH = 7. Carboxylated CNTs in aqueous phase have p K a < 5, and pectin has p K a = 2.9 . Accordingly, at pH = 7, most carboxylic acids are in the deprotonated form (COO − ), which makes it easy to cross‐link carboxylate groups of functionalized CNTs with carboxylic groups of pectin through positive Ca 2+ ions.…”

Section: Methodsmentioning

confidence: 99%

π‐Plasmon absorbance films of carboxylic functionalized CNTs coupled with renewable PGP platforms

Fares

2018

Polymers for Advanced Techs

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π‐Plasmon absorbance films of carboxylic functionalized multiwall carbon nanotubes (CNTs) coupled with renewable and recycled polycaprolactone grafted pectin (PGP) platforms as successful alternative for ordinary nondegradable platforms were investigated. Characterization of the synthesized carboxylic functionalized CNTs was performed using 1H NMR and attenuated total reflectance Fourier transform infrared for structural identification, thermogravimetric analysis and derivative thermogravimetric analysis for thermal stability, and X‐ray powder diffraction for crystal structure, whereas the characterization of prepared PGP was done by means of attenuated total reflectance Fourier transform infrared for chemical structure, differential scanning calorimetry for melting endotherms of polycaprolactone and high crystalline structure of PGP, and thermogravimetric analysis and derivative thermogravimetric analysis for thermal stability of PGP. Fabrication of water‐dispersed carboxylic functionalized CNTs coupled with PGP films was performed by casting technique in the presence of Ca2+ as cross‐linker. The thin films were tested for π‐plasmon absorbance using UV‐Vis spectrometry. Different fractions of carboxylic functionalized CNTs and PGP films demonstrated π‐plasmon absorbance broad peaks at λmax = 232 nm, which corresponded to 5.36 eV. The fabrication of novel films from renewable recycled PGP platform and advanced carboxylic functionalized CNTs properties will be the key features for many of next forthcoming technologies. The PGP considered as environment‐friendly and easily degradable platforms will be a successful alternative for conventional nondegradable electronic platforms, and water‐dispersed carboxylic functionalized CNTs with advanced properties will be finding accelerating executive applications.

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Density functional theory prediction of p K a for carboxylated single-wall carbon nanotubes and graphene

Cited by 10 publications

References 48 publications

pH Modeling to Predict SWCNT–COOH Gas Sensor Response to Multiple Target Gases

pH Modeling to Predict SWCNT–COOH Gas Sensor Response to Multiple Target Gases

Differences in Neonicotinoid and Metabolite Sorption to Activated Carbon Are Driven by Alterations to the Insecticidal Pharmacophore

π‐Plasmon absorbance films of carboxylic functionalized CNTs coupled with renewable PGP platforms

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