SlideShare a Scribd company logo
1 of 6
Download to read offline
See	discussions,	stats,	and	author	profiles	for	this	publication	at:	https://www.researchgate.net/publication/246545654
Soluble	colloidal	manganese	dioxide:
Formation,	identification	and	prospects	of
application
Article		in		Colloid	Journal	·	August	2013
DOI:	10.1134/S1061933X13050049
CITATIONS
4
READS
482
2	authors:
Some	of	the	authors	of	this	publication	are	also	working	on	these	related	projects:
Self	Association	of	Surfactants	and	Supramolecular	Interactions-	Polymer-Surfactant,	Ionic	Liquid-
Surfactant	and	Other	Promising	Systems	View	project
Sustainable	Development:	South	Asian	Conundrum	View	project
Md.	Aminul	Islam
La	Trobe	University,	Bendigo,	Victoria,	Australia
18	PUBLICATIONS			6	CITATIONS			
SEE	PROFILE
M.	Muhibur	Rahman
University	of	Dhaka
58	PUBLICATIONS			218	CITATIONS			
SEE	PROFILE
All	content	following	this	page	was	uploaded	by	Md.	Aminul	Islam	on	23	July	2014.
The	user	has	requested	enhancement	of	the	downloaded	file.
КОЛЛОИДНЫЙ ЖУРНАЛ, 2013, том 75, № 5, с. 591–595
591
1
INTRODUCTION
Soluble colloidal MnO2 is commonly produced by
the reduction of Mn ion in aqueous solution using
a large number of reductants including Mn2+
ion [1].
Under suitable condition, the reduction of Mn ion
yields brown though transparent solutions with a char
acteristic absorption spectrum. The formation of re
duced entities is monitored by measuring the absor
bance of the reaction mixture at around 400 nm, and
making necessary corrections for the contribution of
the starting materials.
During the process, the concentration of MnO2
gradually decreases until the certain stage of the reac
tion is reached; then, the concentration shows an
abrupt decrease [1]. Initially, the forming Mn species
was thought to be those of Mn(V) [2, 3]. The later in
vestigations have found that only soluble form of
Mn(IV) is formed and it has been preliminary identi
fied as H2MnO3 [4, 5].
Colloidal nature of forming manganese com
pounds presenting as soluble colloidal MnO2 has been
recently established [6–11]. The spectrum of MnO2
1
Corresponding author E mail: aminulchem.as@aust.edu or
aminulchem@gmail.com.
O4
–
O4
–
shows a broad band with a wide maximum at 400 nm
covering the entire visible region, and the absorbance
uniformly decreases with increasing wave length [12].
The colloidal MnO2 has been used as the autocatalyst
in many reactions of permanganate [8, 13–17].
Colloidal MnO2 has been prepared by the reduc
tion of KMnO4 by Na2S2O3 [11] or by Mn(ClO4)2 in
aqueous solutions [13], and also by MnSO4 in the
presence of sodium polyphosphate [18]. To develop
new methods for the formation of colloidal MnO2, we
prepared MnO2 by the reduction of KMnO4 by three
different reducing agents in neutral aqueous solution
at 25°C and characterized them by chemical analysis.
To the best of our knowledge, the reduction of KMnO4
by a combination of MnSO4, Na2S2O3 and HCOOH
under described conditions has not yet been reported.
EXPERIMENTAL
Materials and methods
All chemicals used in this work were of reagent
grade: KMnO4, Na2S2O3 ⋅ 5H2O, MnSO4 ⋅ H2O, KI
were purchased from BDH, NaHCO3, H2SO4, NaCl,
KCl, KBr, CuSO4, Al2(SO4)3, HCOOH were pur
SOLUBLE COLLOIDAL MANGANESE DIOXIDE: FORMATION,
IDENTIFICATION AND PROSPECTS OF APPLICATION
© 2013 г. Md. Aminul Islama, 1
and M. Muhibur Rahmanb
a
Department of Arts and Science, Faculty of Engineering, Ahsanullah University of Science and Technology (AUST)
Dhaka, Bangladesh
bUniversity Grants Commission of Bangladesh Agargaon
Dhaka, Bangladesh
Поступила в редакцию 09.10.2012 г.
Soluble colloidal MnO2 was prepared by the reduction of KMnO4 by three reducing agents as MnSO4,
Na2S2O3 and HCOOHin neutral aqueous solutions at 25°C. Under suitable conditions, these solutions were
dark brown in color and found to remain stable and transparent for several weeks. The obtained colloid was
characterized by spectrophotometric and coagulation methods. The spectral behavior of soluble colloidal
MnO2 was studied. The λmax was 390 nm when MnO2 was prepared by the reduction of KMnO4 by MnSO4.
Both the λmax and the molar extinction coefficient depended on the method of preparation of colloidal
MnO2. The formation of MnO2 was confirmed by the determination of the oxidation state of Mn species in
MnO2. The behavior of as prepared colloidal solution obeys Beer Lambert law, if the concentrations of the col
loidal particles are assumed to be equal to Both spectral analysis and that using Rayleigh’s law con
firmed the existence of colloidal MnO2. The observed coagulating efficiency depends not only on the concen
tration of electrolyte but also on the charge carried by the cation of the electrolyte. Stability of the colloidal par
ticles in the aqueous solutions is determined by the negative charge on the surface of the colloidal particles.
DOI: 10.7868/S0023291213050042
4 0[ ] .−
MnO
УДК 541.18
4*
ISSN 1061933X Colloidal Journal, 2013, Vol. 75, No. 5, pp. 591–595. © Pleiades Publishing, Ltd., 2013. Springer
592
КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013
ISLAM, RAHMAN
chased from Merck. To prepare aqueous solutions, the
double distilled water was used.
The absorbance measurements and spectral analy
sis were carried out by using a double beam UV Visible
spectrophotometer, Shimadzu model UV 1650 PC,
Japan.
The instrument was furnished with 1 cm quartz
cell and spectral data processing facilities. The sensi
tivity of the equipment was of 0.002 absorbance unit at
a signal to noise ratio of 1. The temperature of the cell
was maintained at 25°C and controlled with an accu
racy of ±0.1°С.
Preparation of the colloid
Method 1. Colloidal MnO2 was prepared by the re
duction of KMnO4 by MnSO4 in neutral aqueous solu
tion. 25 mL of 1.0 × 10–4
M KMnO4 solution and
37.5 mL of 1.0 × 10–4 M MnSO4 solution were mixed
together in a 250 mL beaker, the solution was homog
enized afterwards by gentle stirring. A dark brown so
lution was obtained and remained transparent for sev
eral weeks. The reaction proceeds as follows:
The concentration of MnO2 in solution was consid
ered to be equal to that of the Mn species, assuming
that all the Mn species are converted into MnO2. The
concentration of as prepared solution was 1.0 × 10–4
M.
Method 2. The colloid was prepared by the reduc
tion of KMnO4 by Na2S2O3 in neutral aqueous solution,
according to the following stoichiometric relation:
4 4
2
4 .
−
+ −
+ + =
= + +
2
2
2MnO 3MnSO 2H O
5MnO 4H 3SO
2 2
4 3 4 .− − + −
+ + = + +2 2 28MnO 3S O 2H 8MnO H O 6SO
The amounts of KMnO4 (1.0 × 10–4
M) and
Na2S2O3 (1.0 × 10–4 M) were taken in the ratio 8 : 3.
Method 3. 30 mL of 1.0 × 10–4
M HCOOH aque
ous solution was added to 20 mL of 1.0 × 10–4 M
KMnO4 solution in a drop wise manner. The colloid
instantly formed in the vigorously stirred mixture,
when the oxidant and reductant were taken in the ra
tion 2 : 3.
The reaction proceeds as follows:
RESULTS AND DISCUSSION
Molar extinction coefficient for solution
In order to determine the oxidation state of the
Mn species in the formed colloidal solution of MnO2,
it is necessary to evaluate small concentrations of io
dine by conversion of I2 to ions, which is deter
mined spectrophotometrically. First, the value of the
molar extinction coefficient of solution at its ab
sorption maximum 351 nm is to be found. The con
centration of saturated I2 solution was determined by
titration and it was found to be 0.613 × 10–3
M and one
order of magnitude lower after the dilution. Figure 1a
shows the spectrum of the diluted iodine solution.
Then, 0.5 g of KI was added to 10 mL of the iodine so
lution under continuous shaking. The equilibrium is
rapidly established:
4
.
− +
+ + =
= + +2 2 2
2MnO 3HCOOH 2H
2MnO 4H O 3CO
I3
–
I3
–
I3
–
( ) ( ) ( )2I aq I aq I aq3 .− −
+
0.9
0.6
0.3
0
700600500300200 400
Wavelength, nm
Absorbance
(а)
0.8
0.6
0.2
0
500400300200 350
Wavelength, nm
Absorbance
(b)
600450250 550
0.4
1.0
Fig. 1. (a) Absorbance spectrum of 6.13 × 10–4
M saturated I2 solution. (b) Absorbance spectrum of 6.13 × 10–6
M tri iodide
solution.
КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013
SOLUBLE COLLOIDAL MANGANESE DIOXIDE: FORMATION, IDENTIFICATION 593
Taking into account the ratio [I–
]/[I2] > 20 and a
value of Kc = 600 at room temperature for the above
reaction, it can be assumed that practically 99% of the
I2, which was present in solution, were converted into
the The total concentration in this solution was
therefore taken as 0.613 × 10–5 M; the spectrum for
this solution is given in Fig. 1b. The solutions of with
various concentrations (1.839 × 10–5
, 2.452 × 10–5
,
3.678 × 10–5 and 4.904 × 10–5 M, respectively) were
prepared and measured accordingly.
The Beer–Lambert plot obtained with these data
yielded a value of 24,125 M–1
cm–1
at 351 nm as a molar
extinction coefficient (ε) for (Fig. 2) which is in good
agreement with that published in the literature [19].
Identification of Colloidal MnO2
Iodometric determination of the oxidation state of
manganese in the colloid. To determine the oxidation
state of manganese in the colloid solution, first, a gram
of NaHCO3 was mixed with 2.0 mL of 2 M H2SO4,
15 mL of water, and 0.5 g of KI. After dissolving, 2.0 mL
of 1.0 × 10–4
M MnO2 solution was added and the en
tire mixture was diluted it with water up to 25 mL of
total volume. The absorbance of the as prepared mix
ture was 0.241 a.u. at 351 nm. A control experiment
without colloid was carried out in the same fashion;
the absorbance of the control mixture was 0.035 a.u.
The A351(colloid) was calculated as A351(experimental) –
⎯ A351(control) = (0.241 – 0.035) = 0.206 a.u.
The oxidation state of Mn species of MnO2 was
calculated as follows
The determined oxidation state of Mn species in
MnO2 was (+4), which confirms the presence of col
loidal MnO2 in the solution.
Absorption spectra of the colloidal solution of
MnO2. Figure 3 shows the spectra of 1.0 × 10–4 M
MnO2 solutions prepared by the reduction of 1.0 ×
× 10–4
M KMnO4 by MnSO4 (spectrum a), Na2S2O3
(spectrum b), and HCOOH solutions (spectrum c),
respectively. These spectra show broad bands covering
the whole visible region with absorption maxima at
around 390 nm. At longer wavelengths, the absorbance
decreases exponentially, which is a characteristic fea
ture of colloidal MnO2.
These spectral patterns are comparable with those
of colloidal MnO2 obtained by the reduction of per
manganate with various reductants [12]. However, the
spectra differ slightly from each other by some charac
teristics such as the maximum absorbance, the λmax,
the peak area etc.
3.−
I 3
−
I
I3
–
3
−
I
4
(2 0.206 25)
2 . .
(2 24125 1 1.0 10 )
OS −
× ×
= + = +
× × × ×
4 13
Colloidal MnO2 obtained using Method 1 was also
characterized by the standard spectra of KMnO4 solu
tion and its product with MnSO4. The spectrum of
pure KMnO4 exhibits an absorption band at λmax =
= 525 nm with ε = 24,00 M–1
cm–1
(Fig. 3d). This
band gradually disappeared, whereas a single broad
band of high intensity appeared at 390 nm upon addi
tion of MnSO4. This result is consistent with our pre
vious observations [20, 21] and confirms the forma
tion of colloidal MnO2.
Molar extinction coefficient of colloidal MnO2.
Figure 4a shows the spectra of MnO2 obtained by the
reduction of KMnO4 by MnSO4 (Method 1). Molar
extinction coefficient of MnO2 was determined by
measuring the absorbance at 390 nm in aqueous solu
tions of several concentrations within the range (0.48–
1.00) × 10–4
M.
A390 values were plotted against the concentration of
MnO2 to obtain molar extinction coefficient; the value of
= 6.987 M–1
cm–1
was found from the slope ac
cordingtoBeer–LambertlawasshowninFig.4b. Molar
extinction coefficient of MnO2 obtained by Method 2
was found to be 6.336 M–1 cm–1 that is in a good agree
ment with literature data [13, 18].
The fitting of experimental data to Rayleigh’s law.
As it is illustrated by Fig. 3b, the spectrum of MnO2
shows a maximum at 390 nm and then the absorbance
always decreases at longer wavelength region, which
does not present any distinct peaks. This spectral pat
tern suggests that the absorption does not contribute
significantly, and only the scattering determines spec
ε 2MnO
1.5
1.0
0 5431 2
[I3
–
] × 105
, M
Absorbance at 351 nm
0.5
5
Fig. 2. A plot of absorbance of solution at 351 nm as a
function of concentration of at 25°C.
3
−
I
3
−
I
594
КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013
ISLAM, RAHMAN
0.20
0.15
0.10
0.05
0
800700600400300200 500
Wavelength, nm
Absorbance
(а)
0.6
0.5
0.3
0.1
0
800700600400300200 500
Wavelength, nm
Absorbance (b)
0.2
0.4
0.3
0.1
0
800700600400300200 500
Wavelength, nm
Absorbance (d)
0.2
0.4
1
2
0.1
0
800700600400300200 500
Wavelength, nm
Absorbance (c)
0.2
0.3
Fig. 3. Absorbance spectra of 1.0 × 10–4
M MnO2 solution prepared by the reduction of 1.0 × 10–4
M KMnO4 by (a) 1.0 × 10–4
M
MnSO4, (b) 1.0 × 10–4
Na2S2O3, and (c) 1.0 × 10–4
M HCOOH solution. (d) Absorbance spectra of (1) 1.0 × 10–4
M KMnO4
and (2) the reaction product MnO2 obtained by Method 1.
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
800700600400300200 500
Wavelength, nm
Absorbance (а)
1
2
3
4
0.8
0.7
0.6
0.5
0.4
0.3
0.1
0 1.00.80.60.40.2
[MnO2] × 104
, M
Absorbance at 390 nm
(b)
0.2
Fig. 4. (a) Absorbance spectra of MnO2 at various concentrations: (1) 1.0 × 10–4
, (2) 0.80 × 10–4
, (3) 0.48 × 10–4
, and (4) 0.24 ×
× 10–4
M. (b) The plot of absorbance of colloidal MnO2 obtained by Method 1 at 390 nm as a function of its concentration;
T = 25°C.
КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013
SOLUBLE COLLOIDAL MANGANESE DIOXIDE: FORMATION, IDENTIFICATION 595
tral response at long wavelengths. For these condi
tions, the Rayleigh’s equation can be applied in a form
A = Cλ–4
, where A is the absorbance, C is the propor
tionality constant and λ is the wavelength.
A plot of logA vs. lgλ for λ ≥ 400 nm gives a straight
line with a slope of –4.2 which is close to –4.0 as pre
dicted for light scattering by colloidal particles by Ray
leigh’s law (Fig. 5).
The confirmation of the formation of colloidal
MnO2. To confirm the presence of MnO2 in the colloi
dal form, the equimolar amounts of various electro
lytes were separately added to the as prepared aqueous
MnO2 at 25°C and stirred. The precipitate of MnO2
was separated by centrifugation. The absorbance of
MnO2 before and after the addition of electrolytes (for
filtered fraction) was measured. To determine the co
agulating efficiency of electrolytes, the experiments
were carried out by using monovalent cations with
similar charge (Na+
, K+
), divalent Cu2+
and trivalent
Al3+
cations. The time required for the precipitation
correlate to the coagulating efficiency of electrolytes.
We found that the coagulating efficiency increases
with the concentration and the charge of the cations.
CONCLUSION
In summary, we suggested three novel methods of
formation of colloidal manganese dioxide. The ob
tained results showed that the absorption maximum,
which typically appears at 390 nm in the spectrum of
MnO2, can be observed at shorter wavelength at about
360 nm and that the spectral pattern of formed system
depends on the preparation procedure. We believe that
our results are of potential interest for practical appli
cations. Colloidal MnO2 is known to possess catalytic
activity towards oxidation of hydrocarbons as well as
volatile organic compounds. Soluble colloidal MnO2
provides a path of preparing highly dispersed support
ed catalysts by impregnating it from its colloidal solu
tion. The transparent sols of MnO2 are also of practical
importance because of participation of MnO2 as inter
mediate or reaction products or autocatalyst in most
permanganate oxidation reactions. Some preliminary
investigations of this aspect were performed in the au
thor’s laboratory and the results seem encouraging.
ACKNOWLEDGEMENTS
The authors are grateful to Prof. Dr. Mohammad
Yousuf Ali Mollah, Dr. Md. Abu Bin Hasan Susan, As
sociate Prof. and Mohammed Shah Miran, Assistant
Professor, Department of Chemistry, University of
Dhaka, for their valuable suggestions and help.
REFERENCES
1. Mata Parez, F. and Perez Benito, J.F., Can. J. Chem.,
1985, vol. 63, p. 988.
2. Lee, D.G. and Brownridge, J.R., J. Am. Chem. Soc.,
1973, vol. 95, p. 3033.
3. Wiberg, K.B., Deutsch, C.J., and Rocek, J., J. Am.
Chem. Soc., 1973, vol. 95, p. 3034.
4. Lee, D.G. and Brownridge, J.R., J. Am. Chem. Soc.,
1974, vol. 96, p. 5517.
5. Simandi, L.I. and Jaky, M., J. Am. Chem. Soc., 1976,
vol. 98, p. 1995.
6. Mata Perez, F. and Perez Benito, J.F., J. Phys. Chem.
Leipzig, 1986, vol. 267, p.120.
7. Mata Perez, F. and Perez Benito, J.F., Can. J. Chem.,
1985, vol. 63, p. 1275.
8. Lee, D.G. and Perez Benito, J.F., Can. J. Chem., 1985,
vol. 63, p. 1275.
9. Freeman, F. and Chang, L.Y., J. Am. Chem. Soc., 1986,
vol. 108, p. 4504.
10. Insausti, M.J., Mata Perez, F., and Alvarez Macho, P.,
Int. J. Chem. Kinet., 1992, vol. 24, p. 411.
11. Perez Benito, J.F. and Arias, C., J. Colloid Interface
Sci., 1992, vol. 149, p. 92.
12. Holba, V. and Košicka, R., Collect. Czech. Chem. Com
mun., 1997, vol. 62, p. 849.
13. Lume Pereira,C.,Baral,S.,Henglein,A.,andJanata,E.,
J. Phys. Chem., 1985, vol. 89, p. 5772.
14. Lee, D.G. and Chen, T., J. Amer. Chem. Soc., 1989,
vol. 111, p. 7534.
15. Perez Benito, J.F., Arias, C., and Amat, E., J. Colloid
Interface Sci., 1996, vol. 177, p. 288.
16. de Andres, J., Brillas, E., Garrido, J.A., and Perez Beni
to, J.F., J. Chem. Soc., Perkin Trans., 1988, vol. 2, p. 107.
17. Šumichrast, R. and Holba, V., Collect. Czech. Chem.
Commun., 1993, vol. 58, p. 1777.
18. Horvath, O. and Strohmayer, K., J. Photochem. Photo
biol., A, 1998, vol. 116, p. 69.
19. Perez Benito, J.F., Arias, C., and Amat, E., J. Colloid
Interface Sci., 1996, vol. 177, p. 288.
20. Perez Benito, J.F., Brillas, E., and Pouplana, R., J. In
org. Chem., 1989, vol. 28, p. 390.
21. Khan, Z., Raju, Akram, M., and Kabir ud Din, Int. J.
Chem. Kinet., 2004, vol. 36, p. 359.
0
–0.5
–1.0
–1.5
–2.0
3.02.92.82.72.6
lgλ [nm]
lg A
Fig. 5. A plot of lgA vs. lgλ obtained for the region 400–
800 nm of the spectrum of MnO2 formed by the reduction
of KMnO4 by Na2S2O3.
View publication statsView publication stats

More Related Content

What's hot

Permanganometry, iodometry in analytical technique, P K MANI
Permanganometry, iodometry in analytical technique, P K MANIPermanganometry, iodometry in analytical technique, P K MANI
Permanganometry, iodometry in analytical technique, P K MANIP.K. Mani
 
Potassium permanganate, potassium dichromate – one of the excellent tools of ...
Potassium permanganate, potassium dichromate – one of the excellent tools of ...Potassium permanganate, potassium dichromate – one of the excellent tools of ...
Potassium permanganate, potassium dichromate – one of the excellent tools of ...Istiqur Rahman
 
Removal of chromium by adsorption
Removal of chromium by adsorptionRemoval of chromium by adsorption
Removal of chromium by adsorptionPriyank Dafda
 
Redox titration
Redox titrationRedox titration
Redox titrationSHILPA JOY
 
Oxidation reduction titrations
Oxidation reduction titrationsOxidation reduction titrations
Oxidation reduction titrationsvanessawhitehawk
 
Formal potential analytical technique, P K MANI
Formal potential analytical technique, P K MANIFormal potential analytical technique, P K MANI
Formal potential analytical technique, P K MANIP.K. Mani
 
Potassium permanganate titrations
Potassium permanganate titrationsPotassium permanganate titrations
Potassium permanganate titrationsHardeep Kaur
 
Iodimetry & iodometry
Iodimetry & iodometryIodimetry & iodometry
Iodimetry & iodometryApusi Chowdhury
 
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...Al Baha University
 
Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...
Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...
Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...IOSRJAC
 
ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG
ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG
ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG Berklin
 
Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...
Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...
Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...IJMERJOURNAL
 

What's hot (16)

Permanganometry, iodometry in analytical technique, P K MANI
Permanganometry, iodometry in analytical technique, P K MANIPermanganometry, iodometry in analytical technique, P K MANI
Permanganometry, iodometry in analytical technique, P K MANI
 
Potassium permanganate, potassium dichromate – one of the excellent tools of ...
Potassium permanganate, potassium dichromate – one of the excellent tools of ...Potassium permanganate, potassium dichromate – one of the excellent tools of ...
Potassium permanganate, potassium dichromate – one of the excellent tools of ...
 
Removal of chromium by adsorption
Removal of chromium by adsorptionRemoval of chromium by adsorption
Removal of chromium by adsorption
 
10redox jntu pharmacy
10redox jntu pharmacy10redox jntu pharmacy
10redox jntu pharmacy
 
Redox titration
Redox titrationRedox titration
Redox titration
 
Oxidation reduction titrations
Oxidation reduction titrationsOxidation reduction titrations
Oxidation reduction titrations
 
Formal potential analytical technique, P K MANI
Formal potential analytical technique, P K MANIFormal potential analytical technique, P K MANI
Formal potential analytical technique, P K MANI
 
Potassium permanganate titrations
Potassium permanganate titrationsPotassium permanganate titrations
Potassium permanganate titrations
 
Iodimetry & iodometry
Iodimetry & iodometryIodimetry & iodometry
Iodimetry & iodometry
 
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
 
Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...
Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...
Adsorptive Removal of Methylene Blue Using Groundnut Shell Activated Carbon C...
 
ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG
ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG
ADSORPTION OF DIRECT RED 23 BY MICROWAVE ACTIVATED LD SLAG
 
Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...
Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...
Adsorption of Methylene Blue From Aqueous Solution with Vermicompost Produced...
 
4. redox titrations
4. redox titrations4. redox titrations
4. redox titrations
 
Chapter 7 acid base
Chapter 7 acid baseChapter 7 acid base
Chapter 7 acid base
 
Topic 4 3
Topic 4 3Topic 4 3
Topic 4 3
 

Similar to Soluble colloidal manganese dioxide: Formation, identification and prospects of application

Preparation of colloidal manganese dioxide
Preparation of colloidal manganese dioxide Preparation of colloidal manganese dioxide
Preparation of colloidal manganese dioxide Sagar Dutta
 
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...Al Baha University
 
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Al Baha University
 
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Al Baha University
 
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Al Baha University
 
Determine the strength in grams per litre of a given ag no3 solution being pr...
Determine the strength in grams per litre of a given ag no3 solution being pr...Determine the strength in grams per litre of a given ag no3 solution being pr...
Determine the strength in grams per litre of a given ag no3 solution being pr...Mithil Fal Desai
 
Cu doped to zno
Cu doped to znoCu doped to zno
Cu doped to znoalisanim2
 
Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...
Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...
Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...ijtsrd
 
Determine the strength in grams per litre of a given AgNO3 solution being pro...
Determine the strength in grams per litre of a given AgNO3 solution being pro...Determine the strength in grams per litre of a given AgNO3 solution being pro...
Determine the strength in grams per litre of a given AgNO3 solution being pro...Mithil Fal Desai
 
PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...
PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...
PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...Dr. Md. Aminul Islam
 
Spectroscopic methods IR part 1
Spectroscopic methods IR part 1Spectroscopic methods IR part 1
Spectroscopic methods IR part 1Chris Sonntag
 
Biosoption of heavy metals by orange peel
Biosoption of heavy metals by orange peelBiosoption of heavy metals by orange peel
Biosoption of heavy metals by orange peelAbbas Kazi
 
Quantitative analysis and volumetric analysis
Quantitative analysis and volumetric analysisQuantitative analysis and volumetric analysis
Quantitative analysis and volumetric analysisMussaOmary3
 
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...IJERA Editor
 
chemical oxygen demand -analysis using APHA manual
chemical oxygen demand -analysis using APHA manualchemical oxygen demand -analysis using APHA manual
chemical oxygen demand -analysis using APHA manualSHERIN RAHMAN
 

Similar to Soluble colloidal manganese dioxide: Formation, identification and prospects of application (20)

Preparation of colloidal manganese dioxide
Preparation of colloidal manganese dioxide Preparation of colloidal manganese dioxide
Preparation of colloidal manganese dioxide
 
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
Spectroscopy letters volume 26 issue 3 1993 [doi 10.1080 00387019308011552] s...
 
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
 
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
 
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
Spectroscopy Letters Volume 26 issue 3 1993 [doi 10.1080_00387019308011552] S...
 
Determine the strength in grams per litre of a given ag no3 solution being pr...
Determine the strength in grams per litre of a given ag no3 solution being pr...Determine the strength in grams per litre of a given ag no3 solution being pr...
Determine the strength in grams per litre of a given ag no3 solution being pr...
 
Synthesis of silver nanoparticles presentation
Synthesis of silver nanoparticles presentation Synthesis of silver nanoparticles presentation
Synthesis of silver nanoparticles presentation
 
Cu doped to zno
Cu doped to znoCu doped to zno
Cu doped to zno
 
Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...
Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...
Application of Fe3O4 Sphere Doped with Zn for Enhanced Sonocatalytic Removal ...
 
Determine the strength in grams per litre of a given AgNO3 solution being pro...
Determine the strength in grams per litre of a given AgNO3 solution being pro...Determine the strength in grams per litre of a given AgNO3 solution being pro...
Determine the strength in grams per litre of a given AgNO3 solution being pro...
 
PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...
PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...
PREPARATION AND CHARACTERIZATION OF SOLUBLE COLLOIDAL MANGANESE DIOXIDE AND ...
 
Spectroscopic methods IR part 1
Spectroscopic methods IR part 1Spectroscopic methods IR part 1
Spectroscopic methods IR part 1
 
STUDY OF MOLAR REFRACTION AND POLARISABILITY CONSTANT OF AQUEOUS SOLUTIONS OF...
STUDY OF MOLAR REFRACTION AND POLARISABILITY CONSTANT OF AQUEOUS SOLUTIONS OF...STUDY OF MOLAR REFRACTION AND POLARISABILITY CONSTANT OF AQUEOUS SOLUTIONS OF...
STUDY OF MOLAR REFRACTION AND POLARISABILITY CONSTANT OF AQUEOUS SOLUTIONS OF...
 
Stoichiometry
StoichiometryStoichiometry
Stoichiometry
 
Biosoption of heavy metals by orange peel
Biosoption of heavy metals by orange peelBiosoption of heavy metals by orange peel
Biosoption of heavy metals by orange peel
 
Quantitative analysis and volumetric analysis
Quantitative analysis and volumetric analysisQuantitative analysis and volumetric analysis
Quantitative analysis and volumetric analysis
 
10.1007_s12633-015-9363-y
10.1007_s12633-015-9363-y10.1007_s12633-015-9363-y
10.1007_s12633-015-9363-y
 
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...
Structural and Morphological Properties of Mn-Doped Co3O4 ThinFilm Deposited ...
 
Presentation1
Presentation1Presentation1
Presentation1
 
chemical oxygen demand -analysis using APHA manual
chemical oxygen demand -analysis using APHA manualchemical oxygen demand -analysis using APHA manual
chemical oxygen demand -analysis using APHA manual
 

More from Dr. Md. Aminul Islam

A promising chitosan/fluorapatite composite for efficient removal of lead (II...
A promising chitosan/fluorapatite composite for efficient removal of lead (II...A promising chitosan/fluorapatite composite for efficient removal of lead (II...
A promising chitosan/fluorapatite composite for efficient removal of lead (II...Dr. Md. Aminul Islam
 
Recent innovative research on chromium (VI) adsorption mechanism
Recent innovative research on chromium (VI) adsorption mechanismRecent innovative research on chromium (VI) adsorption mechanism
Recent innovative research on chromium (VI) adsorption mechanismDr. Md. Aminul Islam
 
Opportunities and constraints of using the innovative adsorbents for the remo...
Opportunities and constraints of using the innovative adsorbents for the remo...Opportunities and constraints of using the innovative adsorbents for the remo...
Opportunities and constraints of using the innovative adsorbents for the remo...Dr. Md. Aminul Islam
 
Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...
Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...
Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...Dr. Md. Aminul Islam
 
Manganese oxides and their application to metal ion and contaminant removal f...
Manganese oxides and their application to metal ion and contaminant removal f...Manganese oxides and their application to metal ion and contaminant removal f...
Manganese oxides and their application to metal ion and contaminant removal f...Dr. Md. Aminul Islam
 
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...Dr. Md. Aminul Islam
 
Removal of dye from polluted water using novel nano manganese oxide-based mat...
Removal of dye from polluted water using novel nano manganese oxide-based mat...Removal of dye from polluted water using novel nano manganese oxide-based mat...
Removal of dye from polluted water using novel nano manganese oxide-based mat...Dr. Md. Aminul Islam
 
A review on nickel(II) adsorption in single and binary component systems and ...
A review on nickel(II) adsorption in single and binary component systems and ...A review on nickel(II) adsorption in single and binary component systems and ...
A review on nickel(II) adsorption in single and binary component systems and ...Dr. Md. Aminul Islam
 

More from Dr. Md. Aminul Islam (8)

A promising chitosan/fluorapatite composite for efficient removal of lead (II...
A promising chitosan/fluorapatite composite for efficient removal of lead (II...A promising chitosan/fluorapatite composite for efficient removal of lead (II...
A promising chitosan/fluorapatite composite for efficient removal of lead (II...
 
Recent innovative research on chromium (VI) adsorption mechanism
Recent innovative research on chromium (VI) adsorption mechanismRecent innovative research on chromium (VI) adsorption mechanism
Recent innovative research on chromium (VI) adsorption mechanism
 
Opportunities and constraints of using the innovative adsorbents for the remo...
Opportunities and constraints of using the innovative adsorbents for the remo...Opportunities and constraints of using the innovative adsorbents for the remo...
Opportunities and constraints of using the innovative adsorbents for the remo...
 
Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...
Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...
Metal ion and contaminant sorption onto aluminium oxide-based materials: A re...
 
Manganese oxides and their application to metal ion and contaminant removal f...
Manganese oxides and their application to metal ion and contaminant removal f...Manganese oxides and their application to metal ion and contaminant removal f...
Manganese oxides and their application to metal ion and contaminant removal f...
 
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...
 
Removal of dye from polluted water using novel nano manganese oxide-based mat...
Removal of dye from polluted water using novel nano manganese oxide-based mat...Removal of dye from polluted water using novel nano manganese oxide-based mat...
Removal of dye from polluted water using novel nano manganese oxide-based mat...
 
A review on nickel(II) adsorption in single and binary component systems and ...
A review on nickel(II) adsorption in single and binary component systems and ...A review on nickel(II) adsorption in single and binary component systems and ...
A review on nickel(II) adsorption in single and binary component systems and ...
 

Recently uploaded

BACTERIAL SECRETION SYSTEM by Dr. Chayanika Das
BACTERIAL SECRETION SYSTEM by Dr. Chayanika DasBACTERIAL SECRETION SYSTEM by Dr. Chayanika Das
BACTERIAL SECRETION SYSTEM by Dr. Chayanika DasChayanika Das
 
Loudspeaker- direct radiating type and horn type.pptx
Loudspeaker- direct radiating type and horn type.pptxLoudspeaker- direct radiating type and horn type.pptx
Loudspeaker- direct radiating type and horn type.pptxpriyankatabhane
 
FBI Profiling - Forensic Psychology.pptx
FBI Profiling - Forensic Psychology.pptxFBI Profiling - Forensic Psychology.pptx
FBI Profiling - Forensic Psychology.pptxPayal Shrivastava
 
Total Legal: A “Joint” Journey into the Chemistry of Cannabinoids
Total Legal: A “Joint” Journey into the Chemistry of CannabinoidsTotal Legal: A “Joint” Journey into the Chemistry of Cannabinoids
Total Legal: A “Joint” Journey into the Chemistry of CannabinoidsMarkus Roggen
 
Environmental Acoustics- Speech interference level, acoustics calibrator.pptx
Environmental Acoustics- Speech interference level, acoustics calibrator.pptxEnvironmental Acoustics- Speech interference level, acoustics calibrator.pptx
Environmental Acoustics- Speech interference level, acoustics calibrator.pptxpriyankatabhane
 
EGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer Zahana
EGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer ZahanaEGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer Zahana
EGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer ZahanaDr.Mahmoud Abbas
 
ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...
ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...
ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...Chayanika Das
 
Understanding Nutrition, 16th Edition pdf
Understanding Nutrition, 16th Edition pdfUnderstanding Nutrition, 16th Edition pdf
Understanding Nutrition, 16th Edition pdfHabibouKarbo
 
Think Science: What Are Eclipses, by Craig Bobchin
Think Science: What Are Eclipses, by Craig BobchinThink Science: What Are Eclipses, by Craig Bobchin
Think Science: What Are Eclipses, by Craig BobchinNathan Cone
 
Advances in AI-driven Image Recognition for Early Detection of Cancer
Advances in AI-driven Image Recognition for Early Detection of CancerAdvances in AI-driven Image Recognition for Early Detection of Cancer
Advances in AI-driven Image Recognition for Early Detection of CancerLuis Miguel Chong Chong
 
Food_safety_Management_pptx.pptx in microbiology
Food_safety_Management_pptx.pptx in microbiologyFood_safety_Management_pptx.pptx in microbiology
Food_safety_Management_pptx.pptx in microbiologyHemantThakare8
 
Timeless Cosmology: Towards a Geometric Origin of Cosmological Correlations
Timeless Cosmology: Towards a Geometric Origin of Cosmological CorrelationsTimeless Cosmology: Towards a Geometric Origin of Cosmological Correlations
Timeless Cosmology: Towards a Geometric Origin of Cosmological CorrelationsDanielBaumann11
 
Combining Asynchronous Task Parallelism and Intel SGX for Secure Deep Learning
Combining Asynchronous Task Parallelism and Intel SGX for Secure Deep LearningCombining Asynchronous Task Parallelism and Intel SGX for Secure Deep Learning
Combining Asynchronous Task Parallelism and Intel SGX for Secure Deep Learningvschiavoni
 
CDS Fundamentals of digital communication system UNIT 1 AND 2.pdf
CDS Fundamentals of digital communication system UNIT 1 AND 2.pdfCDS Fundamentals of digital communication system UNIT 1 AND 2.pdf
CDS Fundamentals of digital communication system UNIT 1 AND 2.pdfshubhangisonawane6
 
Presentation about adversarial image attacks
Presentation about adversarial image attacksPresentation about adversarial image attacks
Presentation about adversarial image attacksKoshinKhodiyar
 
6.1 Pests of Groundnut_Binomics_Identification_Dr.UPR
6.1 Pests of Groundnut_Binomics_Identification_Dr.UPR6.1 Pests of Groundnut_Binomics_Identification_Dr.UPR
6.1 Pests of Groundnut_Binomics_Identification_Dr.UPRPirithiRaju
 
AICTE activity on Water Conservation spreading awareness
AICTE activity on Water Conservation spreading awarenessAICTE activity on Water Conservation spreading awareness
AICTE activity on Water Conservation spreading awareness1hk20is002
 
Role of Gibberellins, mode of action and external applications.pptx
Role of Gibberellins, mode of action and external applications.pptxRole of Gibberellins, mode of action and external applications.pptx
Role of Gibberellins, mode of action and external applications.pptxjana861314
 
Speed Breeding in Vegetable Crops- innovative approach for present era of cro...
Speed Breeding in Vegetable Crops- innovative approach for present era of cro...Speed Breeding in Vegetable Crops- innovative approach for present era of cro...
Speed Breeding in Vegetable Crops- innovative approach for present era of cro...jana861314
 

Recently uploaded (20)

BACTERIAL SECRETION SYSTEM by Dr. Chayanika Das
BACTERIAL SECRETION SYSTEM by Dr. Chayanika DasBACTERIAL SECRETION SYSTEM by Dr. Chayanika Das
BACTERIAL SECRETION SYSTEM by Dr. Chayanika Das
 
Loudspeaker- direct radiating type and horn type.pptx
Loudspeaker- direct radiating type and horn type.pptxLoudspeaker- direct radiating type and horn type.pptx
Loudspeaker- direct radiating type and horn type.pptx
 
FBI Profiling - Forensic Psychology.pptx
FBI Profiling - Forensic Psychology.pptxFBI Profiling - Forensic Psychology.pptx
FBI Profiling - Forensic Psychology.pptx
 
Total Legal: A “Joint” Journey into the Chemistry of Cannabinoids
Total Legal: A “Joint” Journey into the Chemistry of CannabinoidsTotal Legal: A “Joint” Journey into the Chemistry of Cannabinoids
Total Legal: A “Joint” Journey into the Chemistry of Cannabinoids
 
Environmental Acoustics- Speech interference level, acoustics calibrator.pptx
Environmental Acoustics- Speech interference level, acoustics calibrator.pptxEnvironmental Acoustics- Speech interference level, acoustics calibrator.pptx
Environmental Acoustics- Speech interference level, acoustics calibrator.pptx
 
EGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer Zahana
EGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer ZahanaEGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer Zahana
EGYPTIAN IMPRINT IN SPAIN Lecture by Dr Abeer Zahana
 
ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...
ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...
ESSENTIAL FEATURES REQUIRED FOR ESTABLISHING FOUR TYPES OF BIOSAFETY LABORATO...
 
Bioenergetics and the role of ATP to drive the beats of life.
Bioenergetics and the role of ATP to drive the beats of life.Bioenergetics and the role of ATP to drive the beats of life.
Bioenergetics and the role of ATP to drive the beats of life.
 
Understanding Nutrition, 16th Edition pdf
Understanding Nutrition, 16th Edition pdfUnderstanding Nutrition, 16th Edition pdf
Understanding Nutrition, 16th Edition pdf
 
Think Science: What Are Eclipses, by Craig Bobchin
Think Science: What Are Eclipses, by Craig BobchinThink Science: What Are Eclipses, by Craig Bobchin
Think Science: What Are Eclipses, by Craig Bobchin
 
Advances in AI-driven Image Recognition for Early Detection of Cancer
Advances in AI-driven Image Recognition for Early Detection of CancerAdvances in AI-driven Image Recognition for Early Detection of Cancer
Advances in AI-driven Image Recognition for Early Detection of Cancer
 
Food_safety_Management_pptx.pptx in microbiology
Food_safety_Management_pptx.pptx in microbiologyFood_safety_Management_pptx.pptx in microbiology
Food_safety_Management_pptx.pptx in microbiology
 
Timeless Cosmology: Towards a Geometric Origin of Cosmological Correlations
Timeless Cosmology: Towards a Geometric Origin of Cosmological CorrelationsTimeless Cosmology: Towards a Geometric Origin of Cosmological Correlations
Timeless Cosmology: Towards a Geometric Origin of Cosmological Correlations
 
Combining Asynchronous Task Parallelism and Intel SGX for Secure Deep Learning
Combining Asynchronous Task Parallelism and Intel SGX for Secure Deep LearningCombining Asynchronous Task Parallelism and Intel SGX for Secure Deep Learning
Combining Asynchronous Task Parallelism and Intel SGX for Secure Deep Learning
 
CDS Fundamentals of digital communication system UNIT 1 AND 2.pdf
CDS Fundamentals of digital communication system UNIT 1 AND 2.pdfCDS Fundamentals of digital communication system UNIT 1 AND 2.pdf
CDS Fundamentals of digital communication system UNIT 1 AND 2.pdf
 
Presentation about adversarial image attacks
Presentation about adversarial image attacksPresentation about adversarial image attacks
Presentation about adversarial image attacks
 
6.1 Pests of Groundnut_Binomics_Identification_Dr.UPR
6.1 Pests of Groundnut_Binomics_Identification_Dr.UPR6.1 Pests of Groundnut_Binomics_Identification_Dr.UPR
6.1 Pests of Groundnut_Binomics_Identification_Dr.UPR
 
AICTE activity on Water Conservation spreading awareness
AICTE activity on Water Conservation spreading awarenessAICTE activity on Water Conservation spreading awareness
AICTE activity on Water Conservation spreading awareness
 
Role of Gibberellins, mode of action and external applications.pptx
Role of Gibberellins, mode of action and external applications.pptxRole of Gibberellins, mode of action and external applications.pptx
Role of Gibberellins, mode of action and external applications.pptx
 
Speed Breeding in Vegetable Crops- innovative approach for present era of cro...
Speed Breeding in Vegetable Crops- innovative approach for present era of cro...Speed Breeding in Vegetable Crops- innovative approach for present era of cro...
Speed Breeding in Vegetable Crops- innovative approach for present era of cro...
 

Soluble colloidal manganese dioxide: Formation, identification and prospects of application

  • 1. See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/246545654 Soluble colloidal manganese dioxide: Formation, identification and prospects of application Article in Colloid Journal · August 2013 DOI: 10.1134/S1061933X13050049 CITATIONS 4 READS 482 2 authors: Some of the authors of this publication are also working on these related projects: Self Association of Surfactants and Supramolecular Interactions- Polymer-Surfactant, Ionic Liquid- Surfactant and Other Promising Systems View project Sustainable Development: South Asian Conundrum View project Md. Aminul Islam La Trobe University, Bendigo, Victoria, Australia 18 PUBLICATIONS 6 CITATIONS SEE PROFILE M. Muhibur Rahman University of Dhaka 58 PUBLICATIONS 218 CITATIONS SEE PROFILE All content following this page was uploaded by Md. Aminul Islam on 23 July 2014. The user has requested enhancement of the downloaded file.
  • 2. КОЛЛОИДНЫЙ ЖУРНАЛ, 2013, том 75, № 5, с. 591–595 591 1 INTRODUCTION Soluble colloidal MnO2 is commonly produced by the reduction of Mn ion in aqueous solution using a large number of reductants including Mn2+ ion [1]. Under suitable condition, the reduction of Mn ion yields brown though transparent solutions with a char acteristic absorption spectrum. The formation of re duced entities is monitored by measuring the absor bance of the reaction mixture at around 400 nm, and making necessary corrections for the contribution of the starting materials. During the process, the concentration of MnO2 gradually decreases until the certain stage of the reac tion is reached; then, the concentration shows an abrupt decrease [1]. Initially, the forming Mn species was thought to be those of Mn(V) [2, 3]. The later in vestigations have found that only soluble form of Mn(IV) is formed and it has been preliminary identi fied as H2MnO3 [4, 5]. Colloidal nature of forming manganese com pounds presenting as soluble colloidal MnO2 has been recently established [6–11]. The spectrum of MnO2 1 Corresponding author E mail: aminulchem.as@aust.edu or aminulchem@gmail.com. O4 – O4 – shows a broad band with a wide maximum at 400 nm covering the entire visible region, and the absorbance uniformly decreases with increasing wave length [12]. The colloidal MnO2 has been used as the autocatalyst in many reactions of permanganate [8, 13–17]. Colloidal MnO2 has been prepared by the reduc tion of KMnO4 by Na2S2O3 [11] or by Mn(ClO4)2 in aqueous solutions [13], and also by MnSO4 in the presence of sodium polyphosphate [18]. To develop new methods for the formation of colloidal MnO2, we prepared MnO2 by the reduction of KMnO4 by three different reducing agents in neutral aqueous solution at 25°C and characterized them by chemical analysis. To the best of our knowledge, the reduction of KMnO4 by a combination of MnSO4, Na2S2O3 and HCOOH under described conditions has not yet been reported. EXPERIMENTAL Materials and methods All chemicals used in this work were of reagent grade: KMnO4, Na2S2O3 ⋅ 5H2O, MnSO4 ⋅ H2O, KI were purchased from BDH, NaHCO3, H2SO4, NaCl, KCl, KBr, CuSO4, Al2(SO4)3, HCOOH were pur SOLUBLE COLLOIDAL MANGANESE DIOXIDE: FORMATION, IDENTIFICATION AND PROSPECTS OF APPLICATION © 2013 г. Md. Aminul Islama, 1 and M. Muhibur Rahmanb a Department of Arts and Science, Faculty of Engineering, Ahsanullah University of Science and Technology (AUST) Dhaka, Bangladesh bUniversity Grants Commission of Bangladesh Agargaon Dhaka, Bangladesh Поступила в редакцию 09.10.2012 г. Soluble colloidal MnO2 was prepared by the reduction of KMnO4 by three reducing agents as MnSO4, Na2S2O3 and HCOOHin neutral aqueous solutions at 25°C. Under suitable conditions, these solutions were dark brown in color and found to remain stable and transparent for several weeks. The obtained colloid was characterized by spectrophotometric and coagulation methods. The spectral behavior of soluble colloidal MnO2 was studied. The λmax was 390 nm when MnO2 was prepared by the reduction of KMnO4 by MnSO4. Both the λmax and the molar extinction coefficient depended on the method of preparation of colloidal MnO2. The formation of MnO2 was confirmed by the determination of the oxidation state of Mn species in MnO2. The behavior of as prepared colloidal solution obeys Beer Lambert law, if the concentrations of the col loidal particles are assumed to be equal to Both spectral analysis and that using Rayleigh’s law con firmed the existence of colloidal MnO2. The observed coagulating efficiency depends not only on the concen tration of electrolyte but also on the charge carried by the cation of the electrolyte. Stability of the colloidal par ticles in the aqueous solutions is determined by the negative charge on the surface of the colloidal particles. DOI: 10.7868/S0023291213050042 4 0[ ] .− MnO УДК 541.18 4* ISSN 1061933X Colloidal Journal, 2013, Vol. 75, No. 5, pp. 591–595. © Pleiades Publishing, Ltd., 2013. Springer
  • 3. 592 КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013 ISLAM, RAHMAN chased from Merck. To prepare aqueous solutions, the double distilled water was used. The absorbance measurements and spectral analy sis were carried out by using a double beam UV Visible spectrophotometer, Shimadzu model UV 1650 PC, Japan. The instrument was furnished with 1 cm quartz cell and spectral data processing facilities. The sensi tivity of the equipment was of 0.002 absorbance unit at a signal to noise ratio of 1. The temperature of the cell was maintained at 25°C and controlled with an accu racy of ±0.1°С. Preparation of the colloid Method 1. Colloidal MnO2 was prepared by the re duction of KMnO4 by MnSO4 in neutral aqueous solu tion. 25 mL of 1.0 × 10–4 M KMnO4 solution and 37.5 mL of 1.0 × 10–4 M MnSO4 solution were mixed together in a 250 mL beaker, the solution was homog enized afterwards by gentle stirring. A dark brown so lution was obtained and remained transparent for sev eral weeks. The reaction proceeds as follows: The concentration of MnO2 in solution was consid ered to be equal to that of the Mn species, assuming that all the Mn species are converted into MnO2. The concentration of as prepared solution was 1.0 × 10–4 M. Method 2. The colloid was prepared by the reduc tion of KMnO4 by Na2S2O3 in neutral aqueous solution, according to the following stoichiometric relation: 4 4 2 4 . − + − + + = = + + 2 2 2MnO 3MnSO 2H O 5MnO 4H 3SO 2 2 4 3 4 .− − + − + + = + +2 2 28MnO 3S O 2H 8MnO H O 6SO The amounts of KMnO4 (1.0 × 10–4 M) and Na2S2O3 (1.0 × 10–4 M) were taken in the ratio 8 : 3. Method 3. 30 mL of 1.0 × 10–4 M HCOOH aque ous solution was added to 20 mL of 1.0 × 10–4 M KMnO4 solution in a drop wise manner. The colloid instantly formed in the vigorously stirred mixture, when the oxidant and reductant were taken in the ra tion 2 : 3. The reaction proceeds as follows: RESULTS AND DISCUSSION Molar extinction coefficient for solution In order to determine the oxidation state of the Mn species in the formed colloidal solution of MnO2, it is necessary to evaluate small concentrations of io dine by conversion of I2 to ions, which is deter mined spectrophotometrically. First, the value of the molar extinction coefficient of solution at its ab sorption maximum 351 nm is to be found. The con centration of saturated I2 solution was determined by titration and it was found to be 0.613 × 10–3 M and one order of magnitude lower after the dilution. Figure 1a shows the spectrum of the diluted iodine solution. Then, 0.5 g of KI was added to 10 mL of the iodine so lution under continuous shaking. The equilibrium is rapidly established: 4 . − + + + = = + +2 2 2 2MnO 3HCOOH 2H 2MnO 4H O 3CO I3 – I3 – I3 – ( ) ( ) ( )2I aq I aq I aq3 .− − + 0.9 0.6 0.3 0 700600500300200 400 Wavelength, nm Absorbance (а) 0.8 0.6 0.2 0 500400300200 350 Wavelength, nm Absorbance (b) 600450250 550 0.4 1.0 Fig. 1. (a) Absorbance spectrum of 6.13 × 10–4 M saturated I2 solution. (b) Absorbance spectrum of 6.13 × 10–6 M tri iodide solution.
  • 4. КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013 SOLUBLE COLLOIDAL MANGANESE DIOXIDE: FORMATION, IDENTIFICATION 593 Taking into account the ratio [I– ]/[I2] > 20 and a value of Kc = 600 at room temperature for the above reaction, it can be assumed that practically 99% of the I2, which was present in solution, were converted into the The total concentration in this solution was therefore taken as 0.613 × 10–5 M; the spectrum for this solution is given in Fig. 1b. The solutions of with various concentrations (1.839 × 10–5 , 2.452 × 10–5 , 3.678 × 10–5 and 4.904 × 10–5 M, respectively) were prepared and measured accordingly. The Beer–Lambert plot obtained with these data yielded a value of 24,125 M–1 cm–1 at 351 nm as a molar extinction coefficient (ε) for (Fig. 2) which is in good agreement with that published in the literature [19]. Identification of Colloidal MnO2 Iodometric determination of the oxidation state of manganese in the colloid. To determine the oxidation state of manganese in the colloid solution, first, a gram of NaHCO3 was mixed with 2.0 mL of 2 M H2SO4, 15 mL of water, and 0.5 g of KI. After dissolving, 2.0 mL of 1.0 × 10–4 M MnO2 solution was added and the en tire mixture was diluted it with water up to 25 mL of total volume. The absorbance of the as prepared mix ture was 0.241 a.u. at 351 nm. A control experiment without colloid was carried out in the same fashion; the absorbance of the control mixture was 0.035 a.u. The A351(colloid) was calculated as A351(experimental) – ⎯ A351(control) = (0.241 – 0.035) = 0.206 a.u. The oxidation state of Mn species of MnO2 was calculated as follows The determined oxidation state of Mn species in MnO2 was (+4), which confirms the presence of col loidal MnO2 in the solution. Absorption spectra of the colloidal solution of MnO2. Figure 3 shows the spectra of 1.0 × 10–4 M MnO2 solutions prepared by the reduction of 1.0 × × 10–4 M KMnO4 by MnSO4 (spectrum a), Na2S2O3 (spectrum b), and HCOOH solutions (spectrum c), respectively. These spectra show broad bands covering the whole visible region with absorption maxima at around 390 nm. At longer wavelengths, the absorbance decreases exponentially, which is a characteristic fea ture of colloidal MnO2. These spectral patterns are comparable with those of colloidal MnO2 obtained by the reduction of per manganate with various reductants [12]. However, the spectra differ slightly from each other by some charac teristics such as the maximum absorbance, the λmax, the peak area etc. 3.− I 3 − I I3 – 3 − I 4 (2 0.206 25) 2 . . (2 24125 1 1.0 10 ) OS − × × = + = + × × × × 4 13 Colloidal MnO2 obtained using Method 1 was also characterized by the standard spectra of KMnO4 solu tion and its product with MnSO4. The spectrum of pure KMnO4 exhibits an absorption band at λmax = = 525 nm with ε = 24,00 M–1 cm–1 (Fig. 3d). This band gradually disappeared, whereas a single broad band of high intensity appeared at 390 nm upon addi tion of MnSO4. This result is consistent with our pre vious observations [20, 21] and confirms the forma tion of colloidal MnO2. Molar extinction coefficient of colloidal MnO2. Figure 4a shows the spectra of MnO2 obtained by the reduction of KMnO4 by MnSO4 (Method 1). Molar extinction coefficient of MnO2 was determined by measuring the absorbance at 390 nm in aqueous solu tions of several concentrations within the range (0.48– 1.00) × 10–4 M. A390 values were plotted against the concentration of MnO2 to obtain molar extinction coefficient; the value of = 6.987 M–1 cm–1 was found from the slope ac cordingtoBeer–LambertlawasshowninFig.4b. Molar extinction coefficient of MnO2 obtained by Method 2 was found to be 6.336 M–1 cm–1 that is in a good agree ment with literature data [13, 18]. The fitting of experimental data to Rayleigh’s law. As it is illustrated by Fig. 3b, the spectrum of MnO2 shows a maximum at 390 nm and then the absorbance always decreases at longer wavelength region, which does not present any distinct peaks. This spectral pat tern suggests that the absorption does not contribute significantly, and only the scattering determines spec ε 2MnO 1.5 1.0 0 5431 2 [I3 – ] × 105 , M Absorbance at 351 nm 0.5 5 Fig. 2. A plot of absorbance of solution at 351 nm as a function of concentration of at 25°C. 3 − I 3 − I
  • 5. 594 КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013 ISLAM, RAHMAN 0.20 0.15 0.10 0.05 0 800700600400300200 500 Wavelength, nm Absorbance (а) 0.6 0.5 0.3 0.1 0 800700600400300200 500 Wavelength, nm Absorbance (b) 0.2 0.4 0.3 0.1 0 800700600400300200 500 Wavelength, nm Absorbance (d) 0.2 0.4 1 2 0.1 0 800700600400300200 500 Wavelength, nm Absorbance (c) 0.2 0.3 Fig. 3. Absorbance spectra of 1.0 × 10–4 M MnO2 solution prepared by the reduction of 1.0 × 10–4 M KMnO4 by (a) 1.0 × 10–4 M MnSO4, (b) 1.0 × 10–4 Na2S2O3, and (c) 1.0 × 10–4 M HCOOH solution. (d) Absorbance spectra of (1) 1.0 × 10–4 M KMnO4 and (2) the reaction product MnO2 obtained by Method 1. 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 800700600400300200 500 Wavelength, nm Absorbance (а) 1 2 3 4 0.8 0.7 0.6 0.5 0.4 0.3 0.1 0 1.00.80.60.40.2 [MnO2] × 104 , M Absorbance at 390 nm (b) 0.2 Fig. 4. (a) Absorbance spectra of MnO2 at various concentrations: (1) 1.0 × 10–4 , (2) 0.80 × 10–4 , (3) 0.48 × 10–4 , and (4) 0.24 × × 10–4 M. (b) The plot of absorbance of colloidal MnO2 obtained by Method 1 at 390 nm as a function of its concentration; T = 25°C.
  • 6. КОЛЛОИДНЫЙ ЖУРНАЛ том 75 № 5 2013 SOLUBLE COLLOIDAL MANGANESE DIOXIDE: FORMATION, IDENTIFICATION 595 tral response at long wavelengths. For these condi tions, the Rayleigh’s equation can be applied in a form A = Cλ–4 , where A is the absorbance, C is the propor tionality constant and λ is the wavelength. A plot of logA vs. lgλ for λ ≥ 400 nm gives a straight line with a slope of –4.2 which is close to –4.0 as pre dicted for light scattering by colloidal particles by Ray leigh’s law (Fig. 5). The confirmation of the formation of colloidal MnO2. To confirm the presence of MnO2 in the colloi dal form, the equimolar amounts of various electro lytes were separately added to the as prepared aqueous MnO2 at 25°C and stirred. The precipitate of MnO2 was separated by centrifugation. The absorbance of MnO2 before and after the addition of electrolytes (for filtered fraction) was measured. To determine the co agulating efficiency of electrolytes, the experiments were carried out by using monovalent cations with similar charge (Na+ , K+ ), divalent Cu2+ and trivalent Al3+ cations. The time required for the precipitation correlate to the coagulating efficiency of electrolytes. We found that the coagulating efficiency increases with the concentration and the charge of the cations. CONCLUSION In summary, we suggested three novel methods of formation of colloidal manganese dioxide. The ob tained results showed that the absorption maximum, which typically appears at 390 nm in the spectrum of MnO2, can be observed at shorter wavelength at about 360 nm and that the spectral pattern of formed system depends on the preparation procedure. We believe that our results are of potential interest for practical appli cations. Colloidal MnO2 is known to possess catalytic activity towards oxidation of hydrocarbons as well as volatile organic compounds. Soluble colloidal MnO2 provides a path of preparing highly dispersed support ed catalysts by impregnating it from its colloidal solu tion. The transparent sols of MnO2 are also of practical importance because of participation of MnO2 as inter mediate or reaction products or autocatalyst in most permanganate oxidation reactions. Some preliminary investigations of this aspect were performed in the au thor’s laboratory and the results seem encouraging. ACKNOWLEDGEMENTS The authors are grateful to Prof. Dr. Mohammad Yousuf Ali Mollah, Dr. Md. Abu Bin Hasan Susan, As sociate Prof. and Mohammed Shah Miran, Assistant Professor, Department of Chemistry, University of Dhaka, for their valuable suggestions and help. REFERENCES 1. Mata Parez, F. and Perez Benito, J.F., Can. J. Chem., 1985, vol. 63, p. 988. 2. Lee, D.G. and Brownridge, J.R., J. Am. Chem. Soc., 1973, vol. 95, p. 3033. 3. Wiberg, K.B., Deutsch, C.J., and Rocek, J., J. Am. Chem. Soc., 1973, vol. 95, p. 3034. 4. Lee, D.G. and Brownridge, J.R., J. Am. Chem. Soc., 1974, vol. 96, p. 5517. 5. Simandi, L.I. and Jaky, M., J. Am. Chem. Soc., 1976, vol. 98, p. 1995. 6. Mata Perez, F. and Perez Benito, J.F., J. Phys. Chem. Leipzig, 1986, vol. 267, p.120. 7. Mata Perez, F. and Perez Benito, J.F., Can. J. Chem., 1985, vol. 63, p. 1275. 8. Lee, D.G. and Perez Benito, J.F., Can. J. Chem., 1985, vol. 63, p. 1275. 9. Freeman, F. and Chang, L.Y., J. Am. Chem. Soc., 1986, vol. 108, p. 4504. 10. Insausti, M.J., Mata Perez, F., and Alvarez Macho, P., Int. J. Chem. Kinet., 1992, vol. 24, p. 411. 11. Perez Benito, J.F. and Arias, C., J. Colloid Interface Sci., 1992, vol. 149, p. 92. 12. Holba, V. and Košicka, R., Collect. Czech. Chem. Com mun., 1997, vol. 62, p. 849. 13. Lume Pereira,C.,Baral,S.,Henglein,A.,andJanata,E., J. Phys. Chem., 1985, vol. 89, p. 5772. 14. Lee, D.G. and Chen, T., J. Amer. Chem. Soc., 1989, vol. 111, p. 7534. 15. Perez Benito, J.F., Arias, C., and Amat, E., J. Colloid Interface Sci., 1996, vol. 177, p. 288. 16. de Andres, J., Brillas, E., Garrido, J.A., and Perez Beni to, J.F., J. Chem. Soc., Perkin Trans., 1988, vol. 2, p. 107. 17. Šumichrast, R. and Holba, V., Collect. Czech. Chem. Commun., 1993, vol. 58, p. 1777. 18. Horvath, O. and Strohmayer, K., J. Photochem. Photo biol., A, 1998, vol. 116, p. 69. 19. Perez Benito, J.F., Arias, C., and Amat, E., J. Colloid Interface Sci., 1996, vol. 177, p. 288. 20. Perez Benito, J.F., Brillas, E., and Pouplana, R., J. In org. Chem., 1989, vol. 28, p. 390. 21. Khan, Z., Raju, Akram, M., and Kabir ud Din, Int. J. Chem. Kinet., 2004, vol. 36, p. 359. 0 –0.5 –1.0 –1.5 –2.0 3.02.92.82.72.6 lgλ [nm] lg A Fig. 5. A plot of lgA vs. lgλ obtained for the region 400– 800 nm of the spectrum of MnO2 formed by the reduction of KMnO4 by Na2S2O3. View publication statsView publication stats