Metal ferrite nanoparticles: Synthesis, characterization, and studies on decontamination of sulfur mustard

Article abstract of DOI:10.1016/j.jallcom.2016.09.083

Mg, Ca, Mn, Co, Ni, Cu, Zn, Mn-Zn, and Co-Zn metal ferrite and mixed metal ferrite nanoparticles were synthesized by co-precipitation method and were characterized by using transmission electron microscopy, X-ray diffraction, and nitrogen adsorption techn

Full text of DOI:10.1016/j.jallcom.2016.09.083

Accepted Manuscript
Metal ferrite nanoparticles: Synthesis, characterization, and studies on
decontamination of sulfur mustard
J. Praveen Kumar, G.K. Prasad, P.V.R.K. Ramacharyulu, Beer Singh, A.R.
Srivastava
PII:
S0925-8388(16)32835-3
10.1016/j.jallcom.2016.09.083
JALCOM 38917
DOI:
Reference:
To appear in: Journal of Alloys and Compounds
Received Date: 18 August 2015
Revised Date: 10 October 2015
Accepted Date: 7 September 2016
Please cite this article as: J. Praveen Kumar, G.K. Prasad, P.V.R.K. Ramacharyulu, B. Singh, A.R.
Srivastava, Metal ferrite nanoparticles: Synthesis, characterization, and studies on decontamination of
sulfur mustard, Journal of Alloys and Compounds (2016), doi: 10.1016/j.jallcom.2016.09.083.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Metal ferrite nanoparticles: synthesis, characterization, and studies on
decontamination of sulfur mustard
J.Praveen Kumar, G.K.Prasad*, P.V.R.K.Ramacharyulu, Beer Singh, A.R.Srivastava.
Defence R&D Establishment, Jhansi Road, 474002, Gwalior, MP, India.
O
S
Cyclization
1,4 Oxathiane
S
-HCl
OH
Cl
S
Chloro ethyl vinyl
sulfide
HCl
Hydrolysis,
H2O
Elimination
-HCl
Cl
S
Hemisulfur mustard
H2O
HCl
H2O
-HCl
Cl
Cl
Sulfur mustard
S
OH
+
S
Metal ferrite
nanoparticles
OH
OH
Thiodiglycol
Hydroxy ethyl vinyl
sulfide
S
O
M
O
M
O
O
M
O M
Surface complexed
alkoxy species

ACCEPTED MANUSCRIPT
Metal ferrite nanoparticles: synthesis, characterization, and studies on
decontamination of sulfur mustard
J.Praveen Kumar*, G.K.Prasad, P.V.R.K.Ramacharyulu, Beer Singh, A.R.Srivastava
Defence R&D Establishment, Jhansi Road, 474002, Gwalior, MP, India.
Abstract
Mg, Ca, Mn, Co, Ni, Cu, Zn, Mn-Zn, and Co-Zn metal ferrite and mixed metal
ferrite nanoparticles were synthesized by co-precipitation method and were
characterized by using transmission electron microscopy, X-ray diffraction, and nitrogen
adsorption techniques. Transmission electron microscopy data indicated the formation
of metal ferrite and mixed metal ferrite nanoparticles with particle sizes varying from 2 to
88 nm. X-ray diffraction data indicated the formation of metal ferrite and mixed metal
ferrite nanoparticles with spinel phase. The metal ferrite nanoparticles were found to be
mesoporous and exhibited surface area values in the range of 62 to 257 m2/g. The
ferrite nanoparticles were used in decontaminating sulfur mustard and the reactions
exhibited first order behavior. Out of them, Ni, Zn, and Co-Zn ferrite nanoparticles
showed greater decontamination efficiency in comparison to other ferrite nanoparticles.
While Ni, Zn, and Co-Zn ferrite nanoparticles decontaminated 99.99% of sulfur mustard
within 10 h other ferrite nanoparticles took about 16 h to degrade the same. The metal
ferrite and mixed metal ferrite nanoparticles degraded toxic sulfur mustard into relatively
______________________________________________
* Corresponding author:
Tel.: +91 751 2390169; Fax: +91 7512341148.
Email address: praveenjella10@gmail.com (J. Praveen Kumar)

ACCEPTED MANUSCRIPT
non toxic products like chloro ethyl vinyl sulfide, hydroxy ethyl vinyl sulfide, hemisulfur
mustard, and 1,4-oxathiane. The promising decontamination properties of metal ferrite
nanoparticles against sulfur mustard were attributed to the basic sites, Lewis acid sites,
and the presence of these sites was confirmed by CO2 and NH3 temperature
programmed desorption.
Keywords: Ferrite nanoparticles, Chemical warfare agents, Sulfur mustard,
Decontamination, Sorbent decontaminant.
1. Introduction
Chemical warfare agents (CWA) are highly poisonous chemicals which show
adverse effects on human beings that are exposed to them. In the defence against
CWA, decontamination action is very important for making the surrounding environment
safe for normal operations and this responsibility cannot be shirked away [1-2].
Nanomaterials-based decontaminants are actively explored for use against CWA. High
surface area and reactive functionalities of nanomaterials are found to assist in the
effective decontamination of polluted surfaces. Nano metal oxides like MgO, CaO,
MnO2, ZnO, CuO, TiO2, CuO-ZnO, etc., [3-12] displayed significant decontamination
properties against CWA.
Metal ferrite (MF) nanoparticles of composition MFe2O4 (M=Co, Ni, Fe, Mn, etc.)
show interesting magnetic, magneto resistive, magneto-optical, adsorption, and reactive
properties which are potentially useful in variety of applications like magnetic energy
storage [13], gas sensors [14], catalysis [15], magnetic based separations [16] etc.
Because of their unique properties resulting from their reduced size, large surface area
2

ACCEPTED MANUSCRIPT
to volume ratio, high adsorption capacity, and availability of surface active sites, the use
of MF nanoparticles was also explored in environmental decontamination applications.
Ikenaga et al. and Ting et al. reported adsorptive removal of H2S from coal gas by
calcium and zinc MFs [17-18]. Nordhei et al. reported adsorptive decomposition of CO2
over Co, Ni, and Zn MF nanoparticles [19]. Ling et al. demonstrated oxidative
adsorption of SO2 on magnesium MF nanospheres [20]. Hui et al. and Xu et al. reported
catalytic oxidation of phenol by Zn-Al and Ni MF’s respectively [16, 21]. They attributed
the role of Lewis acid sites to the exceptional reactive properties of ferrites against
phenol. Glover et al. used Mn, Ni, Co MF as gas phase adsorbents for the removal of
cyanogen chloride from contaminated air. They found that cyanogen chloride
chemisorbed on surface of ferrites due to the coexistence of adsorbed water and OH
groups [22-27]. Owing to their exceptional adsorptive and reactive properties, MF
nanoparticles are expected to show decontamination properties against CWA as well.
HD is one of the persistent CWA’s that cause blisters on exposure. Its mode of action
and toxicity mechanism were already explored [2]. To the best of the authors’
knowledge, there are no reports till date in literature on the decontamination action of
MF nanoparticles on sulfur mustard (HD). Application of the MF nanoparticles as
sorbent decontaminant against contaminated surfaces is interesting, because they can
be used in personal decontamination kits for the decontamination of skin and individual
protective equipments tainted with CWA. They can be sprayed and dabbed on
contaminated surfaces with the help of kits to clean them. After decontamination is
finished; they can be easily removed by applying handy logistics with magnetic field.
3

ACCEPTED MANUSCRIPT
This particular technique of decontatmination may partially preclude chances of direct
exposure to CWA while cleaning contaminated surfaces.
In the present work, Mg, Ca, Mn, Co, Ni, Cu, Zn MF nanoparticles and Mn-Zn,
Co-Zn mixed metal ferrite (MMF) nanoparticles were synthesized by co-precipitation
method and were characterized by X-ray diffraction (XRD), transmission electron
microscopy (TEM), scanning electron microscopy coupled with energy dispersive
analysis of X-rays (SEM-EDAX) and nitrogen adsorption techniques. Decontamination
reactions of HD were studied using gas chromatography (GC) and gas chromatography
coupled with mass spectrometry (GC-MS).
2. Experimental
Magnesium (II) nitrate, calcium (II) nitrate, manganese (II) nitrate, cobalt (II)
nitrate, nickel (II) nitrate, copper (II) nitrate, zinc (II) nitrate, ferric (III) nitrate, zinc (II)
sulfate, manganese (II) chloride, cobalt (II) chloride, sodium hydroxide, acetonitrile, and
dichloromethane (DCM) were obtained from E. Merck India Ltd. Bis (trimethylsilyl)
trifluoroacetamide and thiodiglycol were purchased from Sigma Aldrich chemicals, USA.
HD of 99 % purity was prepared in our laboratory (Caution: this agent is toxic, hence to
be handled by trained personnel equipped with individual protective equipment only).
TEM images of MF and MMF nanoparticles were taken on Tecnai TEM of FEI
make. The samples were suspended in acetone and sonicated for 20 min.
Subsequently, a drop of supernatant dispersion was placed onto a carbon coated
copper grid. XRD patterns were obtained by using the X Pert Pro X-ray diffractometer,
Panalytical, Netherlands using Cu Kα radiation at a high voltage of 40 kV. SEM-EDAX
4

ACCEPTED MANUSCRIPT
data of MF and MMF nanoparticles were recorded on Quanta 400 ESEM of FEI, The
Netherland make. Infrared spectroscopy data was recorded on FT-IR spectrometer of
Thermo scientific, Italy make. Nitrogen isotherm measurements were done on ASAP
2020 surface area analyzer of Micromeritics USA make. CO2 and NH3 temperature
programmed desorption experiments were performed by using a chemisorption
analyzer of Newchrome Technologies P.Ltd, New Delhi make. Moisture content of MF
and MMF nanoparticles was measured by heating them in an oven at 1200 C to
constant weight.
MF nanoparticles were synthesized by co-precipitation method [28]. In this
method 100 ml of 0.5 M solution of M (NO3)2 (M = Mn, Co, Ni, Cu, Zn, Mg, Ca) and 100
ml of 1 M solution of Fe (NO3)3 were prepared separately and mixed while heated to
70°C. Subsequently, 100 ml of 6 M NaOH solution was slowly added to the above
mixture which led to the formation of a brown color precipitate. The temperature of the
solution was maintained at 70°C up to 2.5 h under c onstant stirring condition. The
precipitate was separated by centrifugation at 9000 RPM and washed with excess
amount of water to remove excess hydroxide ions to obtain neutral solid. Finally, the
solid was washed with ethanol and dried at 60°C. Pr ecipitates of cobalt, nickel, copper,
zinc ferrites were calcined at 300°C for 2.5 h. Pre cipitates of magnesium and
manganese ferrites were calcined at 600°C for 4 h. Precipitate of calcium ferrite was
calcined at 700°C for 2.5 h. Cobalt-zinc, manganese -zinc MMF nanoparticles were
synthesized by the method reported in literature [26]. In the case of cobalt-zinc MMF
nanoparticles, 50 ml of CoCl2 (0.5 M), 50 ml of ZnSO4 (0.5 M), and 100 ml of FeCl3 (1
M) solutions were mixed and kept at 80°C under stir ring condition. 1300 ml boiling
5

ACCEPTED MANUSCRIPT
solution of NaOH (0.64 M) was added to above mixture within 10 seconds under
constant stirring and kept at 90°C for 1.5 h. Subs equently, the precipitate was filtered,
washed with excess water, and dried at 600 C. The resulting solid was finally calcined at
300°C for 2 h. MnCl 2 solution was used instead of CoCl2 in the above method for the
synthesis of manganese-zinc mixed ferrite nanoparticles.
Reaction of HD was studied by treating 100 ꢀL of DCM solution containing 5 ꢀL
of HD with 300 mg of MF or MMF nanoparticles. DCM was used to help in the uniform
distribution of HD molecules within the bulk of nanoparticles. Remaining agent was
extracted by acetonitrile at periodic intervals of time until 24 h to study the kinetics of
degradation. The residual HD was extracted by using 5 mL of acetonitrile for five times
(each time 1 mL) in order to ensure the complete extraction. Extracted solution was
quantitatively analyzed by GC equipped with flame ionization detector and BP5 column
(30 m length, 0.5 mm i.d, and 0.5 ꢀm film thickness) under temperature programmed
from 60 to 210 °C at a rate of 8 °C / min. The conc entration of extracted solution was
determined using a calibration curve plotted with standard solutions for accurate
quantification (Fig.SM1 of supplementary materials).The injection port was kept at 240
˚C and the detection port was kept at 250 ˚C.
HP Agilent GC-MS system (5973) in selective ion monitoring in electron
ionization mode was used for characterization and quantification of reaction products
under a temperature programme from 50 to 250 ˚C at a rate of 15 ˚C / min. The
quadrapole mass analyzer, mass source, and interface were kept at 150˚C, 230˚C, and
280˚C. Electron ionization mode was used for ionization of eluted compounds from HP
6

ACCEPTED MANUSCRIPT
5MS column (30 m length, 0.25 mm i.d, and 0.25 ꢀm film thickness). Thiodiglycol was
silylated with bis (trimethylsilyl) trifluoroacetamide to make it amenable for analysis by
GC-MS. 6.35 X 106 ng/mL of HD was taken for studying the product concentration
profiles of HD reaction with MF and MMF nanoparticles using GC-MS.
3. Results and discussion
TEM images of synthesized MF and MMF nanoparticles are shown in Fig. 1(A-I).
The images show the formation of spherical aggregates of MF and MMF nanoparticles.
The nanoparticles might have aggregated to satisfy steric and electrostatic imbalances
existing on their surface. In addition to spherically shaped nanoparticles, nanobelt like
structures with width ranging from 2 to 6 nm and length ranging from 30 to 80 nm are
also observed in MgFe2O4 (Fig.1A). Images of CaFe2O4 and MnFe2O4 indicate (Fig.1B-
2C) formation of plate like nano structures with sizes in the range of 20 to 88 nm.
Images corresponding to CoFe2O4, NiFe2O4, CuFe2O4, and ZnFe2O4 display spherically
shaped nanoparticles with sizes ranging from 2 to 20 nm (Fig.1D-G). Fig.1 (H and I)
represent images of Mn-Zn and Co-Zn MMF nanoparticles of spherical shape that are
uniformly dispersed with sizes ranging from 4 to 15 nm.
The XRD patterns of all MF and MMF nanoparticles are reproduced in Fig.2.
XRD patterns of MF and MMF nanoparticles match with the characteristic diffraction
peaks of spinel system well and no impurity peaks are observed which indicate the
formation of individual metal oxides or metal hydroxides. Crystallite sizes of MF and
MMFnanoparticles were calculated from peak widening at half height using Scherrer
equation. The crystallite sizes of particles were determined to be in the range of 5 to 65
7

ACCEPTED MANUSCRIPT
nm (Table.1). Nickel and zinc MF nanoparticles exhibited relatively broad peaks when
compared to other MF and MMF nanoparticles which indicate their smaller size when
compared to other ferrites. Besides this, EDAX analysis confirmed the presence of
characteristic elements in respective MF and MMF nanoparticles (Fig. SM2).
Nitrogen adsorption-desorption isotherms of all MF and MMF nanoparticles are
shown in Fig 3 (A- I). All the materials show Type IV isotherms with hysteresis
characteristic of mesoporous materials according to IUPAC classification. MgFe2O4,
CaFe2O4, and MnFe2O4 nanoparticles exhibit H3 type hysteresis. It infers the presence
of slit shaped pores formed due to the aggregation of plate like particles and the same
is consistent with TEM data. Whereas, CoFe2O4, NiFe2O4, CuFe2O4, ZnFe2O4, Co-
ZnFe2O4, and Mn-ZnFe2O4 nanoparticles exhibit H2 type hysteresis which indicate the
presence of pores with narrow necks and wide bodies and the results are in good
agreement with data reported in literature [29]. All ferrite nanoparticles exhibited
surface area values in the range 62 to 257 m2/g. NiFe2O4 exhibited high surface area
value when compared to other ferrites. Surface area values of MgFe2O4, CaFe2O4, and
MnFe2O4 nanoparticles were found to be less. It could be ascribed to wider pores
formed due to aggregation of bigger-size particles when compared to the remaining
ferrite nanoparticles and it is supported by TEM images (Fig.1.A-C). Pore size
distribution data and related data are shown in Fig.4. The pore size distribution data
indicate that pores are in mesoporous range in all the ferrite nanoparticles except in
CaFe2O4. CaFe2O4 shows a pore maximum in macro porous range (57 nm) which might
have formed due to aggregation of bigger particles, where remaining ferrite
nanoparticles exhibit pore maxima in mesoporous range which might have formed due
8

ACCEPTED MANUSCRIPT
to aggregation of relatively smaller particles. CoFe2O4, NiFe2O4, CuFe2O4, ZnFe2O4,
Co-ZnFe2O4, and Mn-ZnFe2O4 nanoparticles show pore maxima in the range of 3 to 13
nm. MgFe2O4 and CaFe2O4 nanoparticles show the same in the range of 20 to 30 nm.
Total pore volume values are in the range of 0.22 to 0.44 mL/g and the data are
summarized in Table. 1.
Decontamination efficiency of MF or MMF nanoparticles against HD is depicted
in Fig. 5. Mg, Ca, Mn MF and Mn-Zn MMF nanoparticles decontaminated 96%, 79%,
70%, and 99.99% of HD respectively in 16 h. Whereas, Cu, Co MF nanoparticles
decontaminated 99.99% of HD in 24 h. Ni, Zn MF and Co-.Zn MMF nanoparticles
showed better decontamination efficiency and they decontaminated 99.99% of HD
within 10 h. Amongst the studied ferrite nanoparticles, Ni, Zn MF and Co-Zn MMF
nanoparticles demonstrated best decontamination efficiency against HD. Better
reactivity of these ferrite nanoparticles when compared to Mg, Ca, Mn, Co MF and Mn-
Zn MMF nanoparticles could be attributed to the presence of larger number of reactive
sites. Despite the higher value of surface area, Cu MF nanoparticles showed lesser
reactivity against HD when compared to Zn MF and Mn-Zn, Co-Zn MMF nanoparticles.
The kinetic data indicated the first order behavior of decontamination reactions of
HD with MF and MMF nanoparticles [9]. Rate constant and half life values of reaction of
HD with MF and MMF nanoparticles are presented in Table 1. Among all the materials
Ni, Zn MF and Co-Zn MMF nanoparticles exhibited higher values of rate constants 0.52,
0.51, and 0.52 h-1. Corresponding t1/2 values were 1.33, 1.35, and 1.33 h. In contrast Mn
MF nanoparticles showed least value of rate constant 0.07 h-1 and t1/2 value 9.44 h
9

ACCEPTED MANUSCRIPT
when compared to all other remaining MF and MMF nanoparticles. Large reactivity of
Ni, Zn MF and Co-Zn MMF nanoparticles against HD when compared to Mg, Ca, Mn,
Co, Cu MF and Mn-Zn MMF nanoparticles may be attributed to presence of larger
number of surface hydroxyl groups, Lewis acid sites, and Bronsted acid sites along with
their high surface area to volume ratio [30]. Based on their chemical reactivities against
HD, NiFe2O4 and CuFe2O4 were short listed as representative candidates to MF and
MMF nanoparticles and were characterized by CO2 and NH3 TPD to prove the presence
of basic and acidic sites on their surface. NiFe2O4 was tested for basic sites by CO2
TPD and CuFe2O4 was tested for Lewis acid sites by NH3 TPD. The CO2 TPD data of
NiFe2O4 nanoparticles is shown in Fig. 6(A). The desorption curve shows four peaks
which correlate to three different forms of adsorbed CO2. As per the temperature range
of the CO2 desorption, the peak at 136 ˚C indicates the physisorbed CO2 on the surface,
the two peaks at around 298 and 420 ˚C indicates the presence of medium range basic
sites and the peak at around 653 ˚C indicates existence of strong basic sites on the
surface of NiFe2O4 nanoparticles. This exceptional basicity of NiFe2O4 nanoparticles
can be attributed to the surface oxide anions. Besides this, the NH3 TPD curve of
CuFe2O4 nanoparticles (Fig. 6(B)) shows one broad peak in the range of 260 to 500 ˚C
indicates the presence of medium range acidic sites as well as strong acidic sites.
These acidic sites of CuFe2O4 nanoparticles can be attributed to their Lewis acid sites
(Cu2+ and Fe3+). On the whole, CO2 TPD data of NiFe2O4 nanoparticles indicate the
presence of the 109.5 mmol/g of basic sites along with Lewis acid sites, surface
hydroxyl groups, physisorbed moisture and contributed to decontamination of 0.13
mmol of HD per gram of NiFe2O4 nanoparticles. NH3 TPD data of CuFe2O4
10

ACCEPTED MANUSCRIPT
nanoparticles indicate the presence of 53.6 mmol/g of acidic sites along with basic sites,
surface hydroxyl groups, and physisorbed moisture and contributed to decontamination
of 0.12 mmol of HD per gram of CuFe2O4 nanoparticles. These reactive sites might
have collectively assisted the decontamination of HD into their degraded products
through hydrolysis, elimination, and substitution reactions which have occurred on their
surface. Physisorbed moisture also found to have assisted the hydrolytic
decontamination of HD in the presence of other Lewis acid sites [31]. 3-5 % of moisture
was found to be present on all the MF and MMF nanoparticles.
GC-MS data indicate the formation of chloro ethyl vinyl sulfide (CEVS,
m/z:122,96,87,73), hydroxy ethyl vinyl sulfide (HEVS, m/z:104,85,73,63), 1,4-oxathiane
(Ox, m/z: 104,86,74), hemisulfur mustard (HM, m/z:140,109,91,73,61), thiodiglycol
(TDG, m/z:122,104,91, 61, 43) and divinyl sulfide (DVS, m/z: 85,71,59,53) due to the
reaction of HD with MF or MMF nanoparticles. After reaction, degradation products (un
complexed) were extracted with acetonitrile. TDG was silylated to make it GC
amenable. The products concentration profile of HD reaction with Mg MF nanoparticles
is presented in Fig.7 (A). The concentration of HM increased from 1023000 to 3103000
ng/mL in 4 h and then decreased to 705000 ng/mL in 24 h, whereas the concentration
of TDG increased steadily to 15700 ng/mL in 24 h. This data indicate that formation of
HM was initially faster, and then gradually it decreased due to further conversion of the
same into TDG or surface complexation products. This could be the reason for the
increase and subsequent decrease of concentration of HM. Concentration of CEVS
increased from 82000 to 203000 ng/mL in 4 h, and then decreased to 62000 ng/mL in
24 h. On the other hand, concentration of HEVS increased from 20000 to 93000 ng/mL
11

ACCEPTED MANUSCRIPT
in 16 h and then slightly decreased to 88000 ng/mL in 24 h. The concentration of Ox
also increased from 10000 to 58000 ng/mL in 24 h. Ca, Co, Cu, Zn, Mn-Zn, Co-Zn MF
and MMF nanoparticles (Fig.7 (B, D, F -I) also followed similar trend. HEVS was not
observed in the reaction product of HD on Co, Cu MF and Co-Zn MMF nanoparticles,
whereas Ox was not observed in the reaction products of Cu ferrite nanoparticles. In the
case of Mn MF nanoparticles (Fig.7C), HM increased from 150000 to 943000 ng/mL in
16 h and then slightly decreased to 821000 ng/mL in 24 h. Mn MF nanoparticles
followed similar behavior as Mg MF nanoparticles for the formation of Ox, CEVS, HEVS,
and TDG. In the case of Ni MF nanoparticles (Fig.7E), concentration of CEVS increased
from 173000 to 1498000 ng/mL in 16 h. In contrast, in case of other MF or MMF
nanoparticles a different trend was followed, CEVS concentration increased initially and
then subsequently decreased with the progress in time. In the case of all the MF and
MMF nanoparticles, amount of HM formed was found to be high when compared to all
other observed reaction products detected in GC-MS. It can be attributed to the
presence of large number of Lewis acid sites in all the ferrite nanoparticles. However,
when compared to other MF nanoparticles, formation of CEVS was large in amount on
nickel MF nanoparticles. It indicates the predominate occurrence of elimination reaction
on nickel MF nanoparticles when compared to others; it further indicates the presence
of relatively higher number of basic sites in Ni MF nanoparticles when compared to
others. Remaining products followed similar trend as other ferrite nanoparticles on Ni
MF nanoparticles. These observations are consistent with the previously reported data
[10].
12

ACCEPTED MANUSCRIPT
It is evident from the GC-MS data that, HD degraded into relatively non toxic
products such as CEVS, HEVS, Ox, and TDG on MF and MMF nanoparticles. Lewis
acid and Bronsted acid sites can be attributed for the initial adsorption or formation of
surface complexation products. Subsequently, the adsorbed HD reacts with surface
hydroxyl groups or physisorbed moisture to form HM in the presence of Lewis acid
sites. Further, nucleophilic attack of surrounding physisorbed moisture or surface
hydroxyl groups on HD lead to the formation of TDG via sulfonium ion. Although, MF
and MMF nanoparticles are rich in Lewis acid sites, presence of basic sites cannot be
ruled out and it could be understood from the formation of products like CEVS, HEVS,
and Ox. Due to elimination reaction, HD is converted to CEVS first and then it reacted
with physisorbed water and formed HEVS. Surface complexed HM undergo cyclization
to form Ox (Fig.8). It could also be possible that, HM undergoes elimination reaction to
form HEVS. All these observations are supported by FT-IR data of decontamination of
HD on ferrite nanoparticles. Disappearance of the band at 700 cm-1 (C-Cl), increase of
intensity of band at 3500 cm-1(-OH); and a change in peak pattern in the range of 700-
1800 cm-1 indicate the decontamination of HD and this conclusion is also supported by
GC-MS data. FT-IR data also depict the formation of surface bound alkoxy species, as
a weak peak is observed at ~1100 cm-1 which also is an indication in support of the
above conclusion. The formation of alkoxy species is an indirect indication of the
presence of Lewis acid sites on the surface of MF and MMF nanoparticles. Amount of
these sites was found to be larger in the case of Ni, Zn MF and Co-Zn MMF
nanoparticles, owing to which they have exhibited good reactivity against HD. These
observations are consistent with previously reported literature [31]. These observations
13

ACCEPTED MANUSCRIPT
clearly indicate that MF and MMF nanoparticles have significant reactivity and high
adsorption capacity towards HD and promise the application of these materials in
personal decontamination kits. Usually, the personal decontamination kits containing
above like sorbent materials are used to remove the agents from contaminated skin,
individual protective equipments, and small arms. After removal, surfaces are rendered
safe and the adsorbed agents are chemically degraded thereby avoiding cross
contamination due desorption from used sorbent powder. The MF and MMF
nanoparticles have completely decontaminated HD within 10 h, whereas metal oxide
nanoparticles, metal ion exchanged zeolites, M258 kit, A-100/200 etc., could not
completely decontaminate HD even in 24 h. Fullers earth has been widely used for
rapid cleaning of CWA contaminated surfaces. This material has high surface area and
it immediately absorbs HD and cleans the tainted surfaces, however, the
decontamination process is slow, hence, there are chances for cross contamination due
to desorption from used powder sorbent [32-35]. On the other hand, DS 2 liquid, a well
known and widely used CWA decontaminant detoxified 100 % of HD within 2 minutes.
Although, it rapidly and effectively decontaminated HD, its use is limited on
contaminated skin, small arms, and individual protective equipments due to its
corrosive nature, hence, search for alternative sorbent decontaminant is underway in
military research establishments for cleaning contaminated skin and individual
protective equipments.
4.Conclusions
Metal ferrite and mixed metal ferrite nanoparticles showed significant reactivity
against HD and they degraded HD into hemisulfur mustard, thiodiglycol, chloro ethyl
14

ACCEPTED MANUSCRIPT
vinyl sulfide, hydroxyl ethyl vinyl sulfide, 1,4-Oxathiane. Lewis acid sites, basic sites,
surface hydroxyl groups, and physisorbed moisture present on the surface of ferrite
nanoparticles assisted the occurrence of hydrolysis, elimination, and nucleophilic
substitution reaction and decontaminated HD into non toxic products. Ni, Zn ferrite and
Co-Zn mixed ferrite nanoparticles displayed more reactivity than others due to additional
number of surface functionalities.
Acknowledgements
Authors are grateful to The Director, DRDE, Gwalior for the constant
encouragement. Authors also thankful Prof. Ramesh Chandra, IITR and S.
Chandrashekar for providing facilities. One of the authors, JPK thanks CSIR, New Delhi
for financial support (09/839 (0014)/2011-EMR-I).
Supplementary data
Supplementary data, including Figures SM1 and SM2 associated with this article
can be found in the online version.
References:
[1]. Y.-C. Yang, J.A. Baker, J.R. Ward,Chem. Rev. 92 (1992) 1729-1743.
[2]. T. T. Marrs, R. L. Maynard, F. R. Sidell, chemical warfare agents, Toxicology and
Treatment, Jhon Wiley & Sons Ltd, England, 1996, 1-230.
15

ACCEPTED MANUSCRIPT
[3] G.W. Wagner, P.W. Bartram, O. Kapoor, K.J. Klabunde, J. Phys. Chem. B. 103
(1999) 3225–3228.
[4] G.W. Wagner, O.B. Koper, E. Lucas, S. Decker, K.J. Klabunde, J. Phys. Chem. B.
104 (2000) 5118–5123.
[5] G.K. Prasad, T.H. Mahato, P. Pandey, B. Singh, M.V.S. Suryanarayana, A. Saxena,
K. Shekhar, Micropor. Mesopor. Mater. 106 (1–3) (2007) 256–261.
[6]. G.K. Prasad, T.H. Mahato, Beer Singh, K. Ganesan, P. Pandey, K. Sekhar, J.
Hazard. Mater. 149 (2) (2007) 460-464.
[7] T.H. Mahato, Beer Singh, A.K. Srivastava, G.K. Prasad, A.R. Srivastava, K.
Ganesan, R. Vijayaraghavan, J. Hazard. Mater. 192 (3) (2011) 1890-1895.
[8] G.K. Prasad, T.H. Mahato, B. Singh, K. Ganesan, A.R. Srivastava, M.P. Kaushik,
R. Vijayraghavan, AIChE J. 54 (11) (2008) 2957-2963.
[9] G.K. Prasad, P.V.R.K. Ramacharyulu, K. Batra, Beer Singh, A.R.
Srivastava,K.Ganesan, R. Vijayaraghavan, J. Hazard. Mater. 183 (2010) 847-852.
[10] J. Praveen Kumar, G.K. Prasad, P.V.R.K. Ramacharyulu, P. Garg, K. Ganesan,
Mater. Chem and Phys. 142 (2013) 484-490.
[11] J. Praveen Kumar, P. V. R. K. Ramacharyulu, B. Kamal, P. Karuna Shankar, and
G. K. Prasad, Adv. Porous Mater. 1 (2013) 1–6.
[12] J. Praveen Kumar, P. V. R. K. Ramacharyulu, G. K.Prasad, A. R. Srivastava, Beer
Singh, DOI 10.1007/s10934-014-9876-6.
16

ACCEPTED MANUSCRIPT
[13] N. A. Frey, P. Sheng , C. Kai , S. Shouheng, Chem. Soc. Rev. 38 (2009) 2532-
2542.
[14] A.V. Kadu, S. V. Jagtap, G. N. Chaudhari, Curr. Appl. Phys. 9 (2009) 1246.
[15] V. Polshettiwar, R. Luque, A. Fihri, H. Zhu, M. Bouhrara, J.M. Basset, Chem.
Rev. 111 (2011) 3036.
[16] H. Zhao, Y. Dong, G. Wang, P. Jiang, J. Zhang, L. Wu, K. Li, Chem. Eng. J. 219
(2013) 295-302.
[17] N. Ikenaga, Y. Ohgaito, T. Suzuki, Energy & Fuels. 19 (2005) 170-179.
[18] K. T. Ting, C. C. Han, C. Hsin, T. C. Hung, J. Hazard. Mater. 160 (2008) 482-488.
[19] C. Nordhei, K. Mathisen, I. Bezverkhyy, D. Nicholson, J. Phys. Chem. C. 112
(2008), 6531-6537.
[20] Z. Ling, L. Xinyong, Z. Qidong, Q. Zhenping, Y. Deling, L. Shaomin, H. Xijun, C.
Guohua, J. Hazard. Mater. 184 (2010) 704-709.
[21] A. Xu, M. Yang. Min, R.Qiao, H. Du, C. Sun, J. Hazard. Mater. 147 (2007) 449-
456.
[22] T. G. Glover, J. B. DeCoste, D. Sabo, Z.J. Zhang, Langmuir. 29 (2013) 5500-
5507.
[23] A. Thakur, M. Singh, Ceram. Int. 29 (2003) 50.
17

ACCEPTED MANUSCRIPT
[24] L. Nalbandian, A. Delimitis, V. T. Zaspalis, E. A. Deliyanni, D. N. Bakoyannikis, E.
N. Peleka, Micropor. Mesopor. Mater. 114 (2008) 465.
[25] V. Sepelak, I. Bergmann, A. Feldhoff, P. Heitjans, F. Krumeich, D. Menzel, F. J.
Litterst, S. J. Campbell, K. D. Becker, J. Phys. Chem. C. 111 (2007) 5026-5033.
[26] S. Laurent, D. Forge, M. Port, A. Roch, C. Robic, L. V. Elst, R. N. Muller, Chem.
Rev. 108 (2008) 2064.
[27] C. Nardhei, A. L. Ramstad, D. G. Nicholson, Phys. Chem. Chem. Phys. 10 (2008)
1053-1066.
[28] R. Arulmurugan, B. Jayadevan, G. Vaidyanathan, S. Sendhilnathan, J. Magn.
Magn. Mater. 288 (2005) 470-477.
[29] K. S. W. Singh, Pure & Appl. Chem. 54 (1982) 2201-2218.
[30] S. V. Jadhav, J. K. Mohan, H. C. Bajaj, Catal. Today. 198 (2012) 98-105.
[31] H. Tang, Z. Cheng, H. Zhu, G. Zuo, M. Zhang, Appl. Catal B: Env. 79 (2008) 323-
333.
[32] W. T. Beaudry, G. W. Wagner, J. R. Ward, J. Mol. Cat. 73 (1992) 77-90.
[33] G. W. Wagner, P. W. Bartram, J. Mol. Cat. A. 111 (1996) 175-180.
[34] G. W. Wagner, P.W. Bartram, Langmuir. 15 (1999) 8113-8118.
[35] G. K. Prasad, P.V.R.K Ramacharyulu, J. Praveen kumar, K. Ganesan, B. Singh, J.
Sci. Ind. Res. 71 (2012) 205-209.
18

ACCEPTED MANUSCRIPT
Table 1. Properties of metal ferrite and mixed metal ferrite nanoparticles.
Sample name Surface Total pore Particle
Crystallite Kinetic rate Half life
area
volume
(mL/g)
sizes(nm) size (nm)
(TEM) (XRD)
constant
(t1/2), h
(m2/g)
(K), h-1
A) MgFe2O4
B) CaFe2O4
C) MnFe2O4
D) CoFe2O4
E) NiFe2O4
F) CuFe2O4
G ZnFe2O4
84
0.36
8-47 30
0.16
4.33
67
0.26
0.22
0.34
0.44
0.42
0.42
46-88
20-80
4-20
3-7
65
45
11
5
0.09
0.07
0.28
0.52
0.21
0.51
7.70
9.90
2.48
1.33
3.30
1.35
62
135
257
190
147
2-5
6
2-10
5
H) Co.ZnFe2O4 163
I) Mn.ZnFe2O4 129
0.32
0.34
3-13
4-17
8
9
0.52
0.42
1.33
1.65
19

ACCEPTED MANUSCRIPT
Figure captions
Figure 1. TEM images of A) MgFe2O4, B) CaFe2O4, C) MnFe2O4, D) CoFe2O4 , E)
NiFe2O4 , F) CuFe2O4 , G) ZnFe2O4 , H) Mn.ZnFe2O4 , I) Co.ZnFe2O4 .
Figure 2. X-ray diffraction patterns of metal ferrite and mixed metal ferrite nanoparticles.
Figure 3. Nitrogen adsorption isotherms of A) MgFe2O4, B) CaFe2O4, C) MnFe2O4, D)
CoFe2O4 , E) NiFe2O4 , F) CuFe2O4 , G) ZnFe2O4 , H) Mn.ZnFe2O4 , I) Co.ZnFe2O4 .
Figure 4. Mesopore size distribution (Barrett-Joyner-Halenda) of metal ferrite and mixed
metal ferrite nanoparticles.
Figure 5. HD Decontamination properties of A) MgFe2O4, B) CaFe2O4, C) MnFe2O4, D)
CoFe2O4 , E) NiFe2O4 , F) CuFe2O4 , G) ZnFe2O4 , H) Mn.ZnFe2O4 , I) Co.ZnFe2O4 .
Figure 6 CO2 TPD profile of A) NiFe2O4 and NH3 TPD profile of B) CuFe2O4
nanoparticles.
Figure 7. Product concentration profile of HD reaction on of A) MgFe2O4, B) CaFe2O4,
C) MnFe2O4, D) CoFe2O4 , E) NiFe2O4 , F) CuFe2O4 , G) ZnFe2O4 , H) Mn.ZnFe2O4 , I)
Co.ZnFe2O4 .
Figure 8. Schematic representation of mechanism of HD degradation on metal ferrite
and mixed metal ferrite nanoparticles.
20

ACCEPTED MANUSCRIPT
21

ACCEPTED MANUSCRIPT
22

ACCEPTED MANUSCRIPT
23

ACCEPTED MANUSCRIPT
311
220
511
511
440
400
I
311
440
220
H
G
400
400
311
301
440
521
213
402
F
311
440
440
E
D
400
400
311
511
333
200
311
112
404
C
211
220
040
331
122
131
011
B
A
311
440
220
400
511
30
40
50
60
70
2θ
Figure 2
24

ACCEPTED MANUSCRIPT
A
C
B
200
200
150
100
50
200
150
100
50
150
100
50
0
0
0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
Relative pressure P/Pº
Relative pressure (P/Pº)
Relative pressure (P/Pº)
F
D
E
200
150
100
50
200
150
100
50
200
150
100
50
0
0
0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
Relative pressure (P/Pº)
Relative pressure P/Pº
Relative pressure (P/Pº)
I
H
G
200
150
100
50
200
200
150
100
50
150
100
50
0
0
0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
Relative pressure (P/Pº)
Relative pressure (P/Pº)
Relative pressure (P/Pº)
Figure 3
25

ACCEPTED MANUSCRIPT
CaFe2O4
0.6
MgFe2O4
MnFe2O4
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0.5
0.4
0.3
0.2
0.1
0.0
0
20 40 60 80 100
Pore width (nm)
0
20 40 60 80 100
Pore width (nm)
0
20 40 60 80 100
Pore width (nm)
NiFe2O4
CoFe2O4
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0.6
0.5
0.4
0.3
0.2
0.1
0.0
CuFe2O4
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0
20 40 60 80 100
Pore width (nm)
0
20 40 60 80 100
Pore width (nm)
0
20 40 60 80 100
Pore width (nm)
Mn.ZnFe2O4
0.6
0.6
0.5
0.4
0.3
0.2
0.1
0.0
ZnFe2O4
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Co.ZnFe2O4
0.5
0.4
0.3
0.2
0.1
0.0
0
20 40 60 80 100
Pore width (nm)
0
20 40 60 80 100
Pore width (nm)
0
20 40 60 80 100
Pore width (nm)
Figure 4.
26

ACCEPTED MANUSCRIPT
100
80
60
40
20
0
A
B
C
D
E
F
G
H
I
0
5
10
15
20
Time (h)
Figure 5
27

ACCEPTED MANUSCRIPT
8
136
B
A
260
20
15
10
5
6
298
420
653
4
2
0
0
100 200 300 400 500 600
100 200 300 400 500 600
Temperature (°C)
Temperature (°C)
Figure 6(A and B)
28