Mustard Gas Surrogate Interactions with Modified Porous Carbon

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Mustard gas surrogate interactions with modified porous carbon fabrics: Effect of oxidative treatment Marc Florent, Dimitrios A. Giannakoudakis, and Teresa J. Bandosz Langmuir, Just Accepted Manuscript • DOI: 10.1021/acs.langmuir.7b02047 • Publication Date (Web): 13 Sep 2017 Downloaded from http://pubs.acs.org on September 14, 2017

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Mustard gas surrogate interactions with modified porous carbon fabrics: Effect of oxidative treatment

Marc Florent, Dimitrios A. Giannakoudakis, Teresa J. Bandosz*

Department of Chemistry, The City College of New York, New York, NY 10031 USA

*Whom correspondence should be addressed to. Tel.: (212)650-6017; Fax: (212)650-6107); Email: [email protected]

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ABSTRACT Removal of chemical warfare agent (CWA) surrogates by highly porous carbon textiles were investigated. The carbon cloth was modified by oxidation in a mixture of concentrated sulfuric and nitric acid. This process did not affect a textile structural integrity. The surface properties of the modified textiles were investigated and their capabilities to remove 2-chloroethyl ethyl sulfide (CEES) and diethylsulfide (EES), two mustard gas surrogates, were evaluated. The oxidized carbon textiles have a highly active surface that has the ability to form radical species. This enhances the degradation of the surrogates, and so the detoxification efficiency. The reaction products detected suggest differences in degradation mechanisms which depend on the type of fabric surface features. Thus, the oxidized surfaces eliminate CEES mainly through dehydrohalogenation, while the non-oxidized surfaces act via hydrolysis. Only the oxidized carbon has a surface active enough to react with the less reactive surrogate EES, by cleavage of the C-S bond. The surface functional groups promote not only the radical formation but also contribute to a strong adsorption of the CWA surrogates, which enhance the decomposition of these toxic species.

Introduction A possibility of chemical warfare deployment either in battle fields or by terrorists against civil population,1,

2, 3

creates

an urgent need for a new protective equipment for military

personnel and for an emergency services. Gas masks with canisters filled with impregnated activated carbon are one of the mostly used protection media.4 Besides them, efficient HazMat suits to protect the body from any contact with a chemical warfare agent (CWA) are also in a high demand. Those should be made of materials that prevent any penetration of CWA, can


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adsorb CWA or can catalytically detoxify warfare agents.5 Such suits often add to the burden of the personnel that wear them by causing overheating, dehydration, or loss of dexterity. 6 All of these resulted in extensive research efforts towards the development of multifunctional reactive materials that could not only adsorb CWAs but also degrade them with a minimal effects on the physical comfort of the personnel who wear garments made of them. Thus, various materials have been recently reported as having detoxification capabilities toward diverse CWAs.

Most of them are metal-based reactive phases, such as metal organic

frameworks,7, 8, 9 TiO2,10, 11 ZnO,12, 13, Zn(OH)2,14, 15 Zr(OH)4,16, 17 Fe2O3.H2O, 18, 19, 20 or mixed metal oxides.21, 22 To find a real life applications these active phases need to be incorporated in fabrics. For instance, it was recently demonstrated that dispersion of ferrihydrite on cotton cloth enhances the reactivity.23 The reactivity also markedly enhanced when photoactive MOF-C3N4 composites were deposited on cotton fabrics.24 In such a case colorimetric sensing indicated the exhaustion level. Other fibers as modified polyamide–based8,

25

or carbon have been also

recently tested for CWAs surrogate detoxification.21, 26, 27 In the case of cotton or synthetic fibers modifications, a fibrous support acts mainly as a catalyst dispersant. Carbon-based textiles, on the other hand, besides being chemically and thermally stable and lightweight, have also the capability to adsorb CWA, not only on external surface, owing to their hydrophobic surface, but also in the pores.28,

29, 30

To the best of the

authors’ knowledge, only few works have been reported on the use of carbon fabrics to detoxify CWAs. The correlation between pore size distributions of various commercial carbon fabrics and the adsorption of 2-chloroethyl ethyl sulfide (CEES) in solution have been reported.27 To utilize that porosity feature activated fibers have to be used. Thus various activation methods of glasscoated carbon fibers to remove CWA surrogates from water have been investgated.31,


32

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Chemical reactivity of carbon nanofibers toward (CEES) has also be shown to be enhanced by loading them with catalytically active metal oxides.21, 33 Nevertheless, most of the detoxification studies were carried out on surrogate solutions. Our recent work on nonporous carbon fiber swatches loaded with copper oxides showed higher reactivity of these materials toward a nerve agent surrogate existing in the vapor phase.26 Taking the above into account, the objective of this paper is to evaluate the detoxification ability of a next generation of elastic carbon fabrics against two mustard gas surrogates, 2chloroethyl ethyl sulfide (CEES) and diethyl sulfide (EES). The experiment have been carried out from the vapor phase, which might be the condition of the real life deployment of mustard gas. As an active phase highly porous carbon cloth obtained from the U.S. Army Natick Soldier Research, Development & Engineering Center was used. These fabrics were modified, characterized and exposed to the blister agent surrogates. As a first step, and to avoid the usage of rather expensive metal based catalysis, as-received and oxidized fabrics were tested. The latter treatment was expected to increase hydrophilicity and surface chemical heterogeneity and thus the chemical transformations and the adsorption of small molecule polar products of surrogate decomposition. The extent of the CEES or EES removal and the type of the reaction products extracted are discussed to understand the chemical reactivity brought by the modifications applied.

Experimental Section Materials Stedcarb carbon cloth from Stedfast Inc. was used in this study. The as-received sample is referred as CC.


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Part of the polymeric layers was mechanically removed after immersing CC in boiling water for 30 min. This blue fabric is referred to as nylon in the discussion. Its amount consists of 30 % of the total mass of CC.

The fabrics after removal of nylon did not lose any elasticity. The

sample obtained in this way is referred to as CCm. CCox was prepared by soaking CC in a mixture of concentrated sulfuric and nitric acid (75/25 v/v) for one day at an ambient temperature. It was then washed in a Soxhlet apparatus and dried at 100 oC. The pictures of CC, CCm, CCox and the removed nylon layer are presented in Figure 1.

Characterization methods Infra-red spectra were collected on a Nicolet 380 spectrometer by attenuated reflectance reflection (ATR-FTIR) using a diamond crystal. X-ray diffractograms were measured on a X'Pert Pro Powder Diffraction diffractometer (PANalytical) using the CuKα radiation. Diffracted X-ray were detected with a PIXcel1D detector between 10 and 70° 2θ with steps of 0.026° 2θ. Nitrogen adsorption isotherms were measured on an ASAP 2020 (Micromeritics) at -196 oC, after degassing the samples at 90 °C to a constant vacuum (10-4 Torr). The surface area (SBET) was calculated using the Brunauer–Emmett–Teller method. The total pore volume, Vtot, was calculated from the last point of the isotherms based on the volume of nitrogen adsorbed and the micropore volume, Vµ, and pore size distribution were calculated using non-linear density functional theory, 2D-NLDFT which assumes the heterogeneity of the pore sizes.34, 35, 36 Potentiometric titration of the textile surface was performed on an 888 Titrando automatic titrator (Metrohm). The textiles were shredded and dispersed in NaNO3 0.1 M solution. The pH was adjusted to about 3.2 with HCl 0,1M and the suspension was titrated with NaOH (0.1 M) up


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to pH ~ 10. The proton binding curves, Q, were derived from the titration data.37 The pKa distributions, f(pKa), of the surface acidic functional groups were calculated by finding stable solutions of the Fredholm integral, relating Q to f(pKa), using the numerical procedure SAIEUS.38, 39 Thermogravimetric (TG) curves were measured with a SDT Q600 (TA instruments). The samples were heated up to 1000 °C at a rate of 10 °C/min in an air flow (100 mL/min). X-ray photoelectron spectra (XPS) were recorded on a PHI 5000 Versaprobe II spectrometer using an Al Kα X-ray radiation (50 W, 15 kV, 1486.6 eV). Measurements were done on a 200 µm diameter analysis area, at a take-off angle of 45° by using a concentric hemispherical analyzer operating in constant-pass-energy mode, at 29.35 eV. Deconvolutions of the spectra were done using MultiPak software. Reactive adsorption of the chemical warfare agent surrogates (CWA) were carried out in hermetically closed horizontal vials. A piece of fabric (20mg)was placed in one end of the vial and 2 mg of 2-chloroethyl ethyl sulfide (CEES) or diethyl sulfide (EES) was spread on the other end. After 24 hours, 1 ml acetonitrile was injected through a septum to extract the non-bonded or weakly bonded unreacted surrogate and reaction products. The solution was shaken and filtered, and analyzed by GC-MS. A drawing of the experimental setup is shown in Figure S1 of the Supplementary Information. Gas chromatography (Shimadzu Q5000) was used to analyze the acetonitrile extracts and measure the extent of the CEES or EES removal. 1 µl of the acetonitrile extract was injected to the column (Restek XTI-5 capillary column, which was heated from 50 to 110 oC at a rate of 5 o

C/min and then to 310 oC at a rate of 40 oC/min. Helium was used a carrier gas. The charge to


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mass ratios of the eluting analytes (m/z between 40 and 300) were detected and characterized by mass spectrometry equipped with an electron ionization detector. Hydroxyl radical formation was evaluated by measuring the fluorescence spectra of terephthalate solution mixed with an adsorbent, on a Jobin Yvon Spex FluoroMax 3 Spectrofluorometer (Horiba). The excitation radiation was set to 312 nm. The ability of samples to form superoxide radical was tested by measuring the UV-vis absorption spectra of nitro blue tetrazolium (NBT) solution mixed with an adsorbent, on a Cary 100 UV-vis spectrophotometer (Agilent) between 200 and 400 nm.

Results and Discussion The received carbon textile consist of 0.4 mm thick fabric made of carbon cloth layer embedded in a polymeric (nylon) outer layer. It was used either as-received, after mechanical removal of nylon, or after oxidation with a sulfuric-nitric acid mixture. The pictures of fabrics used in this study are shown in Figure 1.


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Figure 1: Pictures of the carbon cloths as-received (CC), after oxidation (CCox), after removal of the nylon (CCm) and of the removed nylon layer.

The ATR FTIR spectra of the textiles before and after oxidation or after the removal of the nylon layer are shown in Figure 2A. Absorption bands of N-H of amides (3923, 1535, 692 cm-1), CH2 (2933, 2862 cm-1 for the asymmetric and the symmetric stretching, respectively) and C=O of amides (1632 cm-1) reveal the presence of polyamide layer.40 A comparison of the fingerprint region with reference spectra confirms that it is nylon 6, ̶[CO ̶ (CH2)5 ̶ NH]̶ .41 After the removal of the nylon layer, the IR absorption bands of nylon significantly decrease in their intensity. Nevertheless, visible bands at 3293, 2933, 2862, 1632 and 1535 cm-1 indicate that some nylon remains on the surface of the fabric. The appearance of a band at 1110 cm-1 after removing the nylon indicates the presence of C-O bonds. After oxidation, the sharp peaks corresponding to the organic component disappear. The spectrum for CCox shows a broad band at 1705 cm-1, that corresponds to C=O stretching. A band around 1560 cm-1, is attributed to C=C and a very broad one between 1200 and 900 cm-1 represents to the stretching vibrations of a variety of C-O bonds.


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In addition, a sharp peak at 740 cm-1 is also visible. It is linked to C-H out-of-plane bending vibrations of aromatic compounds.

Figure 2. FTIR spectra of CC and CCox (A). X-ray diffractograms of CC and CCox (B). The carbon phase is indicated by its Miller index and the nylon phase by the Greek letters corresponding to its two crystalline form, α and γ. Nitrogen adsorption isotherms (C) and the pore size distributions (D). The X-ray diffractograms are presented in Figure 2B. The main diffraction peak of CCox centered around 24o 2θ, is slightly broader than that for CC. The main difference between CC and CCox is the disappearance of a diffraction peak at 21o 2θ, which represented the γ phase of 9 ACS Paragon Plus Environment

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nylon and of a small shoulder at 20o 2θ linked to the nylon in the α form.42 The disappearance of those peaks indicates the elimination of nylon chemical features upon oxidation or a marked alteration in the surface chemistry. The physical removal of the nylon layers also lead to the disappearance of the nylon diffraction pattern. The porosity of the carbon textile is markedly affected by oxidation. The nitrogen adsorption isotherms and pore size distributions of CC, CCm and CCox are shown in Figure 2C and 2D. The parameters of the pore structure calculated from the isotherms are collected in Table 1. All materials are mostly microporous and exhibit bimodal pore size distributions. The oxidation results in a marked decrease in the specific surface area and in a slight decrease in the pore width. This may be due to a partial filling of the pores by the products released during the oxidation of the nylon component or by incorporation of nitrogen groups to the carbon matrix, which might result in a pore blocking. It is important to note that the nylon layer that contributes to about 30 % of the CC mass, is not porous. The physical removal of the nylon nonporous layer results in a marked increase of the CCm surface area and volume of micropores. Interestingly, pore sizes are not affected.

Table 1: The parameters of the porous structure calculated from the nitrogen adsorption measurements. w1 and w2 are the pore widths corresponding to the two maxima of the pore size distribution. Sample CCm CC CCox

SBET (m2/g) 922 556 337

Vtot (cm3/g) 0.45 0.30 0.19

Vµ (cm3/g) 0.39 0.23 0.16

Vµ/Vtot (%) 86.7 76.7 84.2

w1 | w2 (Å) 6.5 | 16.3 6.5 | 16.7 5.9 | 13.4

The oxidative treatment, besides removing the polymer coating, is expected to forms functional groups on the surface of the carbon fibers. The textile features of the carbon cloth are 10 ACS Paragon Plus Environment

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not damaged after this treatment and the elasticity is still prevented. Nevertheless, the change in the fabric color is visible-( Fig. 1) and the thickness decreased about half from 0.4 mm to 0.2 mm, as shown in Fig. S2 of Supplementary Information. The changes in the stability of the textiles caused by oxidation were analyzed by thermal analysis (Figure 3A). The peaks on the DTG curve of CC at temperature lower than 550 oC represent the decomposition of the nylon layer. They do not appear on the DTG curves of the oxidized textile or of CCm, where only the peak of carbon oxidation/decomposition is revealed at 550 oC or 610 oC respectively. Interestingly, before oxidation, the carbon phase decomposed at 630 oC. This significant decrease in the carbon decomposition temperature might be an effect of the presence of oxygen- or nitrogen- containing groups. The latter are known as oxygen activators.43 The higher amount of water released (below 100 oC) after oxidation than that in the case of the initial sample, indicates an increase in the hydrophilicity level of the oxidized sample.


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B

1.4

CC CCox CCm

-1.0

1.2

80 1.0

Weight (%)

0.0 -0.5

Q (mmol/g)

/ / /

60 0.8

0.6 40

0.4 20 0.2

-1.5 -2.0 -2.5

CC CCox CCm

-3.0 -3.5 3

C

4

5

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pH

7

8

9

10

CC CCox CCm

3.5 3.0

f(pKa) (mmol/g)

A 100

Weight derivative (%/oC)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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2.5 2.0 1.5 1.0 0.5

0 200

400

600

Temperature (oC)

800

0.0 1000

0.0 2

4

6

pKa

8

10

Figure 3: TG and DTG curves of CC, CCm and CCox in air (A). Proton binding curves (B) and pKa distributions (D) of the groups present on the surface of the carbon textile as-received and after oxidation or removal of the nylon layer. The potentiometric titration results presented in Figure 3B and C confirm the changes in the surface chemistry of the textile upon oxidation. The as-received carbon fabrics surface is slightly basic, almost neutral. While the removal of the nylon layer did not affect

the distribution of

acidic groups, the surface became very acidic after oxidation, which is seen by a marked proton release. The pKa distributions derived from the proton binding curves, reveal the formation of a large amount of functional groups of pKa ranging from 3 to 10. The amount of functional groups


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increases from 0.3 mmol/g for CC to 3.6 mmol/g for CCox. On CCm 0.4 mmol/g of acidic groups were detected. The surface chemistry of the carbon textiles was further studied by XPS. The XPS spectra and their deconvolutions are shown in Figure S3 of the supplementary Information. Due to the low penetration depth of XPS measurement, the recorded spectrum of CC is mostly due to the electrons scattered by the polymeric nylon layer. The results of the deconvolution of C1s core energy level spectra presented in Table 2 shows that CCm contains less oxygen than the other materials, which is expected since the nylon layer is removed and the materials is not oxidized. After oxidation of CC, the oxygen on the surface of CCox is mainly in phenols and carbonyls. There is also a small contribution of carboxylic acids. This is consistent with the potentiometric titration results. Apparently after oxidation and the decomposition of nylon, nitrogen is incorporated to the carbon matrix in the form of pyridines and pyridine–N oxides, whose contributions markedly increased compared to those in the CC sample. It is a very important finding since these species bring positively charged sites to the carbon surface, which might affect the reactive adsorption process.44, 45 The ratio of pyridine and pyridine-N-oxides on CCm is higher than that on CC. The almost equal content of oxygen on the surface of CC and CCox is an apparent result. For the former sample, nylon coating is the main contribution to it, as it is for the nitrogen content of CC, and for the latter ‒ it is the results of the incorporation of oxygen to the carbon matrix, as seen based on the deconvolution of C1s core energy level spectrum. Interestingly, CC, CCm and CCox contains a small amount of sulfur which must have its origin in the carbon phase itself and/or it was probably added to the nylon as a flame retardant.46, 47 For CCox, it could also originate from the oxidation mixture (HNO3 + H2SO4). This sulfur in sulfonic groups markedly increases the surface polarity and acidity.


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Table 2: Results of the deconvolution of the XPS spectra of C 1s, O 1s, N 1s and S 2p. The element content is given in bold letters. Binding energy, eV C 1s 284.8 285.0 286.2-286.4 287.9 288.4-288.7 289.4-289.5 N 1s 398.2-398.6 399.9-400.4 401.1 401.9 O 1s 531.7-531.9 532.5-533.4 S 2p3/2 168-168.5

Bond assignment

C-C sp2 C-C sp3, CH C-N (amine, amide), C-O (phenol, alcohol, ether) O=C-N (amide) C=O (carbonyl, quinone), O-C-O (acetal) O=C-O (carboxyl, ester) Pyridine pyrrole/pyridone/amide/amine quaternary nitrogen/ammonium pyridine-N-oxide, C-N+O-C, NOx C=O in amide,carbonyl,quinone or sulfoxide,sulfone carboxyl, phenol, alcohol, sulfonic acid R-SO3 (sulfonic), N-SO3 (sulfamic)

CC % 71.2 67.0 22.7 8.7 1.6 5.7 5.71 83.7 10.6 22.7 64.7

CCox % 77.0 73.6 16.0 6.6 3.8 2.0 17.5 52.6 29.9 20.4 61.6

CCm % 81.2 71.0 18.5 6.9 3.6 4.9 11.8 83.4 4.8 13.5 -

35.3 0.4 100

38.4 0.6 100

100 0.5 100

The functionalization of the carbon textile should result in changes in its surface activity. Thus, the ability of CC and CCox to form superoxide O2 or hydroxyl HO radicals in water was

tested. The UV absorption of NBT reveals that it is not affected by the presence of CC or CCox (Figure S4). This indicates that superoxide radicals are not formed.48 However, a terephthalate solution shows an increase of its fluorescence intensity in the presence of CCox, but not in that of CC or CCm (Figure 4). This is due to the formation of hydroxylterephthalate and it indicates the formation of hydroxyl radical HO on the surface of CCox at ambient conditions (light and temperature).49


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4.5x105 4.0x105

Emission intensity (a.u.)

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5

3.0x10

2.5x105 2.0x105 1.5x105 1.0x105 0

50

100

150

200

250

300

350

Time (min)

Figure 4: Maximum fluorescent emission of a terephthalate solution in the presence of CC, CCm or CCox.

The textiles were exposed to chemical warfare agent surrogates, CEES and EES (10 % of the fabric mass) for one day, at ambient light and temperature. The unreacted and weakly bonded reagents and reaction products were extracted with acetonitrile and analyzed by GC-MS. The chromatograms are shown in Figure S5. They were used to calculate the conversion ratio of CEES and EES (in percentage of agent that has been removed) (Figure 5). We use such quantity since owing to the toxicity of the surrogate and a broad spectrum of species which can be formed the fully quantitative analysis is extremely difficult. The results show that all materials have abilities to remove the mustard gas surrogates. In the case of CEES, CC shows a relatively low detoxification capability with a conversion of about 33 %. After the removal of the nylon layer CCm shows a very low conversion of about 11 %. The conversion on nylon alone was also low


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(15 %). The smaller conversions on both CCm and nylon as compared to that on CC indicate a synergistic effect of the nylon deposition on the carbon fabrics. After oxidation of the carbon fabrics, the conversion of CEES increases from 33 to 81 % indicating the positive effect of the surface functionalization.

100 90

CEES EES

80

Conversion (%)

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70 60 50 40 30 20 10 0 CCm

Nylon

CC

CCox

Figure 5: Conversion of CEES and EES after one day contact with nylon, CCm, CC and CCox cloths.

Interestingly, in the case of EES, nylon fabric itself showed 67 % conversion ratio. CCm, on the other hand showed again a poor reactivity with a conversion of 10 %. When nylon was associated with carbon in CC, the conversion falls to 45 %. However, this value is still higher than the hypothetical value that would be expected from the physical mixture of nylon (30 %) and CCm (70 %), as shown in Figure S6. This shows again the synergistic catalytic effect of the deposition of the nylon layer on the carbon fabrics. Interestingly, after the oxidative treatment, and despite of the nylon decomposition and reduced porosity, the conversion of EES increases to 65 %.


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In order to understand the reactivity of our samples towards CEES and EES, the reaction products extracted with acetonitrile were analyzed by GC/MS (Figure S5). After exposure to EES, the only detected product besides EES is diethyl disulfide (DEDS), and it is detected only in the case of the CCox sample. Other samples do not show any reaction products in the acetonitrile extracts. The small amount of extracted reaction product indicates that EES is strongly adsorbed on the textiles, without a further degradation. This can be attributed to the high porosity of the materials, but also, when nylon is present, to the numerous polar sites of the polymer that can electrostatically attract sulfide, as shown in Figure 6A.50 Only the carbon fabric containing the oxidized and highly active surface, CCox, further degraded EES by breaking the C-S bond. This is owing to its ability to form thiyl radical with the involvement of HO radicals (Figure 6B).51, 52 The action of these radicals is enhanced by the strong adsorption of EES via its S atom on positively charged centers on the carbon surface resulting from the incorporation of nitrogen in pyridines (positively charged carbon ) and in nitrogen N-oxide ( positive charge is on nitrogen). The limited performance of CC and CCm is attributed to the lack of surface groups (beside the nylon polymer in CC), which could contribute to strong retention of EES via hydrogen bonding,53 and to the lack of HO radicals. The high amount of OH groups on the surface of CCox might trigger the formation of these radicals. The nitrogen groups incorporated to the carbon condensed aromatic rings can also contribute to the catalytic breaking of the C-S bond by increasing the strength of CWA adsorption.54


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A

B

Figure 6: adsorption of EES on nylon fabrics (A) and reaction of EES on the surface of CCox (B).

For CEES, due to the high reactivity of the C-Cl bond, more reaction products were detected (Table 3). As in the case of EES, a reactivity difference is noticed between CC and CCox. For the former sample the main reaction product is ethyl vinyl sulfide (EVS), followed by hydroxyethyl ethyl sulfide (ESOH), while for the latter one ESOH is the main reaction product. In this case no EVS was detected. Interestingly, the surface of CCm, similarly to that of CC forms both EVS and ESOH, but compared to CC, there is less EVS and more ESOH produced. The acetonitrile extracts from the surface of CCox exposed to CEES show the presence of BETEE and BETE dimers, and the small amount of mercaptoacetaldehyde (SEO) compounds. The formation of the latter two compounds involves a C-C or C-S cleavage of CEES. In the case of CC only traces of these compounds were detected in the extracts. The removal of the nylon layer results in the formation of more BETEE and BETE on CCm (based on the peaks intensity) than on CC, but still less than those formed on the surface of CCox. This supports the higher 18 ACS Paragon Plus Environment

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surface reactivity of CCox , which must be the result of the heterogeneity of its surface chemistry, pores accessibility and catalytic capability of its surface groups.

Table 3: Products of the reaction between CEES and the fabrics detected in the acetonitrile extracts by GC-MS and their relative percentages. Name, Abbreviation

Formula

Ethyl vinyl sulfide, EVS Hydroxyethyl ethylsulfide, ESOH 2-Chloroethyl ethyl sulfide, CEES Mercaptoacetaldehyde, SEO 1,2Bis(ethylthio)ethane, BETE Bis[2-(ethylthio)ethyl] ether, BETEE

Relative area (%) CC CCm CCox Nylon 3.2

2.2

-

0.3

2.7

14.7

21.7

-

93.8

82.6

76.0

99.7

0.1

0.1

0.9

-

0.1

0.3

0.7

-

0.1

0.2

0.7

-

The results indicate that CC favors an elimination mechanism (E1) of CEES leading to the formation of EVS (Figure 7A), while on CCox a nucleophilic substitution SN1 is favorable (Figure 7B). This inclination toward E1 or SN1 is a direct reflection of the surface properties. Indeed, CC has a more basic surface, so will have more affinity to accept the proton released by CEES during an E1, than has the acidic surface of CCox. Interestingly, CCm shows an intermediate activity with more ESOH formed than on CC, but less than on CCox. Moreover, on its surface EVS was also detected. Nevertheless, that amount of EVS is smaller than that on CC. On CCox surface no EVS was detected. This indicates that nylon deposited on the carbon layer has an active role facilitating the elimination, or preventing the substitution mechanism. The formed hydroxy compounds, ESOH, can further dimerize with CEES to form the BETEE 19 ACS Paragon Plus Environment

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ester (Figure 7C). In addition, the highly reactive surface of CCox can produce radicals that would lead to a C-C or C-S bond cleavage, resulting in the formation of SEO or BETE, respectively (Figure 7D and E).

(A)

(B)

(C) (D)

(E) Figure 7: Reactions between CEES and the CC/CCox surfaces.

In addition, the higher content of sulfur in CCox on the carbon surface, presence of N in pyridines and the appearance of pyridine N-oxide after oxidation can lead to the higher catalytic activity of this fabrics compared to that of CC. These groups promote formation of HO radicals.55,

56, 57

The charged pyridine N-oxides can assist the electron transport through the

carbon matrix, facilitating the formation of these radicals.58 The pyridine functionalities, by providing the positive charge to the carbon matrix can also attract strongly CEES and EES, through their heteroatom, leading to their degradation by the formed radicals.45, 59 This process of adsorption is expected to be strongest in the pores in which these groups can exist and where CEES or EES are adsorbed relatively strong via dispersive forces. Such strong adsorption can


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take place in pores similar in size to CEES and EES molecules. Since CCox is mainly microporous, the chemically active groups formed as a result of the carbon oxidation and nylon decomposition must exist in supermicropores ( >1 nm) and thus they increase not only the adsorption but also the catalytic decomposition.

In addition, oxygen groups provide OH

radicals contributing to an increased decomposition ratio.

Summary and Conclusions A carbon textile made of highly porous carbon and nylon showed a detoxification activity toward CEES and EES, which are the surrogates of mustard gas. It degrades CEES through dehydrohalogenation. EES is mostly adsorbed in the nylon’s amides network. After the mechanical removal of the nylon layer, the carbon layer showed very limited detoxification . This indicates that The nylon layer on the carbon fabrics provides the synergistic effect enhancing reactive adsorption of the surrogates. After chemical oxidation that decomposed nylon layer, N- and O- containing surface groups were added to the carbon matrix and as a result of their catalytic effects the surface reactivity of the carbon textile markedly increased. The degradation of CEES through hydrolysis became the main detoxification mechanism. The surface of the oxidized textile, which also contains sulfur and nitrogen functionalities, attracts the CWAs surrogates via specific interactions and also promotes the formation of radical species that degrade CEES and EES by a bond cleavage. Even though not all adsorbed surrogates were decomposed on the materials tested, the results indicate that a simple and quite “classical” oxidation of the as- received carbon textile, without high energy requirements, modifies it texture and chemistry, while keeping the textile integrity. The modification applied converts the textiles into catalytically active CWA surrogate


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decomposition media. Simultaneous oxidative treatment of both highly carbon textile and nylon layer led to unique surface features enhancing the detoxification ratio

Acknowledgement: This work was supported by Army Research Office (grant No. W91113-0225). The authors are grateful to Dr. Mariusz Barczak for his help with CCm sample.

Supporting Information: Schematic representation of the reactive adsorption setup, picture of the fabrics, XPS spectra and the deconvolutions, UV-vis absorption spectra, gas chromatograms and comparison of the measured to hypothetical conversion of CEES and EES on the as-received carbon textiles are available online


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REFERENCES 1.

Szinicz, L. History of Chemical and Biological Warfare Agents. Toxicology 2005, 214

(3), 167-181. 2.

Jett, D. A. The NIH Countermeasures against Chemical Threats Program: Overview and

Special Challenges. Ann. N. Y. Acad. Sci. 2016, 1374 (1), 5-9. 3.

Zarocostas, J. Syria Chemical Attacks: Preparing for the Unconscionable. The Lancet

2017, 389 (10078), 1501. 4.

Lodewyckx, P. Chapter 10 Adsorption of Chemical Warfare Agents. In Activated Carbon

Surfaces in Environmental Remediation, Bandosz, T. J., Ed.; Elsevier: Amsterdam, 2006; Vol. Volume 7, pp 475-528. 5.

Schreuder-Gibson, H. L.; Truong, Q.; Walker, J. E.; Owens, J. R.; Wander, J. D.; Jones,

W. E. Chemical and Biological Protection and Detection in Fabrics for Protective Clothing. MRS Bulletin 2011, 28 (8), 574-578. 6.

Taylor, H. L.; Orlansky, J. The Effects of Wearing Protective Chemical Warfare Combat

Clothing on Human Performance; DTIC Document, 1991. 7.

Mondloch, J. E.; Katz, M. J.; Isley Iii, W. C.; Ghosh, P.; Liao, P.; Bury, W.; Wagner, G.

W.; Hall, M. G.; DeCoste, J. B.; Peterson, G. W.; Snurr, R. Q.; Cramer, C. J.; Hupp, J. T.; Farha, O. K. Destruction of Chemical Warfare Agents Using Metal–Organic Frameworks. Nat. Mater. 2015, 14 (5), 512-516. 8.

Zhao, J.; Lee, D. T.; Yaga, R. W.; Hall, M. G.; Barton, H. F.; Woodward, I. R.; Oldham,

C. J.; Walls, H. J.; Peterson, G. W.; Parsons, G. N. Ultra-Fast Degradation of Chemical Warfare Agents Using MOF–Nanofiber Kebabs. Angew. Chem., Int. Ed. Engl. 2016, 55 (42), 1322413228. 9.

Giannakoudakis, D. A.; Travlou, N. A.; Secor, J.; Bandosz, T. J. Oxidized g-C3N4

Nanospheres as Catalytically Photoactive Linkers in MOF/g-C3N4 Composite of Hierarchical Pore Structure. Small 2017, 13 (1). 10.

Vorontsov, A. V.; Lion, C.; Savinov, E. N.; Smirniotis, P. G. Pathways of Photocatalytic

Gas Phase Destruction of HD Simulant 2-Chloroethyl Ethyl Sulfide. J. Catal. 2003, 220 (2), 414-423. 23 ACS Paragon Plus Environment

Langmuir

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

11.

Page 24 of 30

Panayotov, D. A.; Paul, D. K.; Yates, J. T. Photocatalytic Oxidation of 2-Chloroethyl

Ethyl Sulfide on TiO2-SiO2 Powders. J. Phys. Chem. B 2003, 107 (38), 10571-10575. 12.

Mahato, T. H.; Prasad, G. K.; Singh, B.; Acharya, J.; Srivastava, A. R.; Vijayaraghavan,

R. Nanocrystalline Zinc Oxide for the Decontamination of Sarin. J. Hazard. Mater. 2009, 165 (1–3), 928-932. 13.

Houšková, V.; Štengl, V.; Bakardjieva, S.; Murafa, N.; Kalendová, A.; Opluštil, F. Zinc

Oxide Prepared by Homogeneous Hydrolysis with Thioacetamide, Its Destruction of Warfare Agents, and Photocatalytic Activity. J. Phys. Chem. A 2007, 111 (20), 4215-4221. 14.

Giannakoudakis, D. A.; Arcibar-Orozco, J. A.; Bandosz, T. J. Key Role of Terminal

Hydroxyl Groups and Visible Light in the Reactive Adsorption/Catalytic Conversion of Mustard Gas Surrogate on Zinc (Hydr)Oxides. Appl. Catal. B-Environ. 2015, 174–175, 96-104. 15.

Giannakoudakis, D. A.; Arcibar-Orozco, J. A.; Bandosz, T. J. Effect of GO Phase in

Zn(OH)2/GO Composite on the Extent of Photocatalytic Reactive Adsorption of Mustard Gas Surrogate. Appl. Catal. B-Environ. 2016, 183, 37-46. 16.

Bandosz, T. J.; Laskoski, M.; Mahle, J.; Mogilevsky, G.; Peterson, G. W.; Rossin, J. A.;

Wagner, G. W. Reactions of VX, GD, and HD with Zr(OH)4: Near Instantaneous Decontamination of VX. J. Phys. Chem. C 2012, 116 (21), 11606-11614. 17.

Giannakoudakis, D. A.; Mitchell, J. K.; Bandosz, T. J. Reactive Adsorption of Mustard

Gas Surrogate on Zirconium (Hydr)Oxide/Graphite Oxide Composites: The Role of Surface and Chemical Features. J. Mater. Chem. A 2016, 4 (3), 1008-1019. 18.

Arcibar-Orozco, J. A.; Bandosz, T. J. Visible Light Enhanced Removal of a Sulfur

Mustard Gas Surrogate from a Vapor Phase on Novel Hydrous Ferric Oxide/Graphite Oxide Composites. J. Mater. Chem. A 2015, 3 (1), 220-231. 19.

Arcibar-Orozco, J. A.; Panettieri, S.; Bandosz, T. J. Reactive Adsorption of CEES on

Iron Oxyhydroxide/(N-)Graphite Oxide Composites under Visible Light Exposure. J. Mater. Chem. A 2015, 3 (33), 17080-17090. 20.

Štengl, V.; Maříková, M.; Bakardjieva, S.; Šubrt, J.; Opluštil, F.; Olšanská, M. Reaction

of Sulfur Mustard Gas, Soman and Agent VX with Nanosized Anatase TiO2 and Ferrihydrite. J. Chem. Technol. Biotechnol. 2005, 80 (7), 754-758.


Page 25 of 30

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

21.

Dadvar, S.; Tavanai, H.; Morshed, M.; Ghiaci, M. The Removal of 2-Chloroethyl Ethyl

Sulfide Using Activated Carbon Nanofibers Embedded with MgO and Al2O3 Nanoparticles. J. Chem. Eng. Data 2012, 57 (5), 1456-1462. 22.

Florent, M.; Giannakoudakis, D. A.; Wallace, R.; Bandosz, T. J. Mixed CuFe and ZnFe

(Hydr)Oxides as Reactive Adsorbents of Chemical Warfare Agent Surrogates. J. Hazard. Mater. 2017, 329, 141-149. 23.

Wallace, R.; Giannakoudakis, D. A.; Florent, M.; Karwacki, C. J.; Bandosz, T.

Ferrihydrite Deposited on Cotton Textiles as Protection Media against the Chemical Warfare Agent Surrogate (2-Chloroethyl Ethyl Sulfide). J. Mater. Chem. A 2017, 5 (10), 4972-4981. 24.

Giannakoudakis, D. A.; Hu, Y.; Florent, M.; Bandosz, T. J. Smart Textiles of MOF/g-

C3N4 Nanospheres for the Rapid Detection/Detoxification of Chemical Warfare Agents. Nanoscale Horizons 2017. 25.

Bromberg, L.; Su, X.; Martis, V.; Zhang, Y.; Hatton, T. A. Self-Decontaminating Fibrous

Materials Reactive toward Chemical Threats. Appl. Mater. Inter. 2016, 8 (27), 17555-17564. 26.

Florent, M.; Giannakoudakis, D. A.; Wallace, R.; Bandosz, T. J. Carbon Textiles

Modified with Copper-Based Reactive Adsorbents as Efficient Media for Detoxification of Chemical Warfare Agents. Appl. Mater. Inter. 2017, 9 (32), 26965-26973. 27.

Kaiser, R.; Kulczyk, A.; Rich, D.; Willey, R. J.; Minicucci, J.; MacIver, B. Effect of Pore

Size Distribution of Commercial Activated Carbon Fabrics on the Adsorption of CWA Simulants from the Liquid Phase. Ind. Eng. Chem. Res. 2007, 46 (19), 6126-6132. 28.

Donnet, J.-B. Carbon Fibers; 3rd ed.; Marcel Dekker: New York, 1998. p viii, 573 p.

29.

Edie, D. D. The Effect of Processing on the Structure and Properties of Carbon Fibers.

Carbon 1998, 36 (4), 345-362. 30.

Minus, M. L.; Kumar, S. The Processing, Properties, and Structure of Carbon Fibers.

Jom-Us 2005, 57 (2), 52-58. 31.

Mangun, C. L.; Yue, Z.; Economy, J.; Maloney, S.; Kemme, P.; Cropek, D. Adsorption

of Organic Contaminants from Water Using Tailored ACFs. Chem. Mater. 2001, 13 (7), 23562360. 32.

Yue, Z.; Economy, J. Nanoparticle and Nanoporous Carbon Adsorbents for Removal of

Trace Organic Contaminants from Water. J. Nanopart. Res. 2005, 7 (4), 477-487.


Langmuir

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

33.

Page 26 of 30

Dadvar, S.; Tavanai, H.; Morshed, M.; Ghiaci, M. A Study on the Kinetics of 2-

Chloroethyl Ethyl Sulfide Adsorption onto Nanocomposite Activated Carbon Nanofibers Containing Metal Oxide Nanoparticles. Sep. Purif. Technol. 2013, 114, 24-30. 34.

Jagiello, J.; Olivier, J. P. 2D-NLDFT Adsorption Models for Carbon Slit-Shaped Pores

with Surface Energetical Heterogeneity and Geometrical Corrugation. Carbon 2013, 55, 70-80. 35.

Jagiello, J.; Olivier, J. P. Carbon Slit Pore Model Incorporating Surface Energetical

Heterogeneity and Geometrical Corrugation. Adsorption 2013, 19 (2), 777-783. 36.

Jagiello, J. SAIEUS, 2.1; http://www.nldft.com/, 2012.

37.

Bandosz, T. J.; Jagiello, J.; Contescu, C.; Schwarz, J. A. Characterization of the Surfaces

of Activated Carbons in Terms of Their Acidity Constant Distributions. Carbon 1993, 31 (7), 1193-1202. 38.

Jagiello, J. Stable Numerical-Solution of the Adsorption Integral-Equation Using Splines.

Langmuir 1994, 10 (8), 2778-2785. 39.

Jagiello, J.; Bandosz, T. J.; Schwarz, J. A. Carbon Surface Characterization in Terms of

Its Acidity Constant Distribution. Carbon 1994, 32 (5), 1026-1028. 40.

Socrates, G.; Socrates, G. Infrared and Raman Characteristic Group Frequencies :

Tables and Charts; 3rd ed.; Wiley: Chichester ; New York, 2001. p xv, 347 p. 41.

Stuart, B. H. Appendix Infrared Spectra of Polymers Absorbance. In Analytical

Techniques in Materials Conservation; John Wiley & Sons, Ltd, 2007, pp 396-403. 42.

Ting, T. M.; Nasef, M. M.; Hashim, K. Tuning N-Methyl-D-Glucamine Density in a New

Radiation Grafted Poly(Vinyl Benzyl Chloride)/Nylon-6 Fibrous Boron-Selective Adsorbent Using the Response Surface Method. RSC Adv. 2015, 5 (47), 37869-37880. 43.

Stöhr, B.; Boehm, H. P.; Schlögl, R. Enhancement of the Catalytic Activity of Activated

Carbons in Oxidation Reactions by Thermal Treatment with Ammonia or Hydrogen Cyanide and Observation of a Superoxide Species as a Possible Intermediate. Carbon 1991, 29 (6), 707-720. 44.

Kumar, B.; Asadi, M.; Pisasale, D.; Sinha-Ray, S.; Rosen, B. A.; Haasch, R.; Abiade, J.;

Yarin, A. L.; Salehi-Khojin, A. Renewable and Metal-Free Carbon Nanofibre Catalysts for Carbon Dioxide Reduction. 2013, 4, 2819. 45.

Gong, K.; Du, F.; Xia, Z.; Durstock, M.; Dai, L. Nitrogen-Doped Carbon Nanotube

Arrays with High Electrocatalytic Activity for Oxygen Reduction. Science 2009, 323 (5915), 760-764. 26 ACS Paragon Plus Environment

Page 27 of 30

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Langmuir

46.

Coquelle, M.; Duquesne, S.; Casetta, M.; Sun, J.; Gu, X.; Zhang, S.; Bourbigot, S. Flame

Retardancy of PA6 Using a Guanidine Sulfamate/Melamine Polyphosphate Mixture. Polymers 2015, 7 (2), 316. 47.

Coquelle, M.; Duquesne, S.; Casetta, M.; Sun, J.; Zhang, S.; Bourbigot, S. Investigation

of the Decomposition Pathway of Polyamide 6/Ammonium Sulfamate Fibers. Polym. Degrad. Stab. 2014, 106, 150-157. 48.

Hayyan, M.; Hashim, M. A.; AlNashef, I. M. Superoxide Ion: Generation and Chemical

Implications. Chem. Rev. 2016, 116 (5), 3029-85. 49.

Page, S. E.; Arnold, W. A.; McNeill, K. Terephthalate as a Probe for Photochemically

Generated Hydroxyl Radical. Journal of Environmental Monitoring 2010, 12 (9), 1658-1665. 50.

Mundlapati, V. R.; Ghosh, S.; Bhattacherjee, A.; Tiwari, P.; Biswal, H. S. Critical

Assessment

of

the

Strength

of

Hydrogen

Bonds

between

the

Sulfur

Atom

of

Methionine/Cysteine and Backbone Amides in Proteins. J. Phys. Chem. Lett. 2015, 6 (8), 13851389. 51.

Barnes, I.; Hjorth, J.; Mihalopoulos, N. Dimethyl Sulfide and Dimethyl Sulfoxide and

Their Oxidation in the Atmosphere. Chem. Rev. 2006, 106 (3), 940-975. 52.

Gupta, V.; Carroll, K. S. Sulfenic Acid Chemistry, Detection and Cellular Lifetime.

Biochim. Biophys. Acta, Gen. Subj. 2014, 1840 (2), 847-875. 53.

Biswal, H. S. Hydrogen Bonds Involving Sulfur: New Insights from Ab Initio

Calculations and Gas Phase Laser Spectroscopy. In Noncovalent Forces, Scheiner, S., Ed.; Springer International Publishing: Cham, 2015, pp 15-45. 54.

Moore, S.; Stein, W. H.; Fruton, J. S. Chemical Reactions of Mustard Gas and Related

Compounds.1 II. The Reaction of Mustard Gas with Carboxyl Groups and with the Amino Groups of Amino Acids and Peptides. J. Org. Chem. 1946, 11 (6), 675-680. 55.

Gomes, H. T.; Miranda, S. M.; Sampaio, M. J.; Figueiredo, J. L.; Silva, A. M. T.; Faria, J.

L. The Role of Activated Carbons Functionalized with Thiol and Sulfonic Acid Groups in Catalytic Wet Peroxide Oxidation. Appl. Catal. B-Environ. 2011, 106 (3), 390-397. 56.

Nakanishi, I.; Nishizawa, C.; Ohkubo, K.; Takeshita, K.; Suzuki, K. T.; Ozawa, T.;

Hecht, S. M.; Tanno, M.; Sueyoshi, S.; Miyata, N.; Okuda, H.; Fukuzumi, S.; Ikota, N.; Fukuhara, K. Hydroxyl Radical Generation Via Photoreduction of a Simple Pyridine N-Oxide by an NADH Analogue. Org. Biomol. Chem. 2005, 3 (18), 3263-3265. 27 ACS Paragon Plus Environment

Langmuir

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

57.

Page 28 of 30

Tian, W.; Zhang, H.; Duan, X.; Sun, H.; Tade, M. O.; Ang, H. M.; Wang, S. Nitrogen-

and Sulfur-Codoped Hierarchically Porous Carbon for Adsorptive and Oxidative Removal of Pharmaceutical Contaminants. Appl. Mater. Inter. 2016, 8 (11), 7184-7193. 58.

Seredych, M.; Hulicova-Jurcakova, D.; Lu, G. Q.; Bandosz, T. J. Surface Functional

Groups of Carbons and the Effects of Their Chemical Character, Density and Accessibility to Ions on Electrochemical Performance. Carbon 2008, 46 (11), 1475-1488. 59.

Zhang, J.; Xia, Z.; Dai, L. Carbon-Based Electrocatalysts for Advanced Energy

Conversion and Storage. Sci. Adv. 2015, 1 (7).


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Captions to the Figures Figure 81: Pictures of the carbon cloths as-received (CC), after oxidation (CCox), after removal of the nylon (CCm) and of the removed nylon layer. Figure 92. FTIR spectra of CC and CCox (A). X-ray diffractograms of CC and CCox (B). The carbon phase is indicated by its Miller index and the nylon phase by the Greek letters corresponding to its two crystalline form, α and γ. Nitrogen adsorption isotherms (C) and the pore size distributions (D). Figure 103: TG and DTG curves of CC, CCm and CCox in air (A). Proton binding curves (B) and pKa distributions (D) of the groups present on the surface of the carbon textile as-received and after oxidation or removal of the nylon layer. Figure 114: Maximum fluorescent emission of a terephthalate solution in the presence of CC, CCm or CCox. Figure 125: Conversion of CEES and EES after one day contact with nylon, CCm, CC and CCox cloths. Figure 136: adsorption of EES on nylon fabrics (A) and reaction of EES on the surface of CCox (B). Figure 147: Reactions between CEES and the CC/CCox surfaces.

Captions to the Tables Table 1: The parameters of the porous structure calculated from the nitrogen adsorption measurements. w1 and w2 are the pore widths corresponding to the two maxima of the pore size distribution. Table 42: Results of the deconvolution of the XPS spectra of C 1s, O 1s, N 1s and S 2p. The element content is given in bold letters. Table 53: Products of the reaction between CEES and the fabrics detected in the acetonitrile extracts by GC-MS and their relative percentages.


Mustard Gas Surrogate Interactions with Modified Porous Carbon

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