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Chapter -3

RESULTS AND DISCSSION

3.1. INTRODUCTION

In nanotechnology, an iron oxide nanoparticle, is defined as a small object that

behaves as a whole unit in terms of its transport and properties. Particles are further

classified according to size: in terms of diameter, fine particles cover a range between

100 and 2500nanometers. On the other hand, ultrafine particles are sized between 1

and 100nanometers. Similar to ultrafine particles, nanoparticles are sized between 1

and 100nanometers. Nanoparticles may or may not exhibit size-related properties that

differ significantly from those observed in fine particles or bulk materials (Buzea et

al., 2007).

Iron oxides are chemical compounds composed of iron and oxygen.

Altogether, there are sixteen known iron oxides and oxyhydroxides (Cornell &

Schwertmann, 2003). The uses of these various oxides and hydroxides are

tremendously diverse ranging from pigments in ceramic glaze, to use in thermite. Iron

(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is of

one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which

is rare, and iron(II,III) oxide (Fe3O4), which also occurs naturally as the mineral

magnetite. As the mineral known as hematite, Fe2O3 is the main source of the iron for

the steel industry. Fe2O3 is paramagnetic, reddish brown, and readily attacked by

acids. Rust is often called iron (III) oxide and to some extent, this label is useful,

because rust shares several properties and has a similar composition.

In the present research work an emphasis has been made to focus on the

synthesis of the iron oxide nano particles, subsequently which were used for the

treatment of MSW by stabilizing process. Before the use of nano particle, they were

characterized by XRD, XRF and SEM techniques. The presences of the functional

group in iron oxide nano particle were characterized through XRF techniques and

SEM was carried to determine the surface feature of the nano particle. Cadmium,

Copper, Lead, Chromium and Mercury are the five Heavy metals considered for

MSW samples and Bottom ash samples.

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Fe2O3

Fe2O3

3.2 Characterization of Fe2O3:

The characterization of Fe2O3 was carried out by using X-ray diffraction

(XRD) and X-ray Fluorescence (XRF) in order to determine the phase and elemental

composition. Subsequently Scanning Electron Microscope (SEM) was recorded to

determine morphological features and Atomic Absorption Spectroscopic analysis was

carried out to determine qualitative analysis of elemental concentration.

3.2.1 XRD technique:

The X-ray diffraction pattern was recorded using diffractogram Rigaku

desktop MiniflexII (SCAN RANGE 6-600). The X-ray diffraction patterns of the

Fe2O3 used in the present work are shown in Figure3.1. In Figure 3.1, all the peaks

matched well with those reported for well crystallized Fe2O3 (JCPDS file No. 24–72),

having rhombohedral structure. On careful observation XRD pattern, we notice the

presence of some additional reflections along with those corresponding to Fe2O3.

Figure.3.1. XRD Pattern of Fe2O3

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3.2.2. XRF Analysis:

X-ray fluorescence spectrum was recorded using Minipal- 4 benchtop model,

with fine focus x-ray tube, MO target of multilayer monochromator of 17.5KeV. The

XRF spectra of Fe2O3 clearly indicate that the presence of Fe+3

(Figure 3.2).

Figure.3.2. XRF Spectra of Fe2O3

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3.2.3 Scanning Electron Microscopy (SEM):

The SEM images were taken by using Scanning electron microscope (Model

EOV LS 15). The surface morphologies of the Fe2O3 were observed by scanning

electron micrographic images as shown in Figure 3.3. SEM image can clearly shows

the particles having various shapes and also estimation of the particle size appeared

very difficult for the samples reported herein specially because of their extremely

small dimension and inherent nature of agglomeration which is obvious due to high

dipole interactions.

Figure.3.3. SEM image of Fe2O3

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FeOOH FeOOH

3.3. Characterization of FeOOH

The characterization of FeOOH was carried out by using X-ray diffraction

(XRD) and X-ray Fluorescence (XRF) in order to determine the phase and elemental

composition. Subsequently Scanning Electron Microscope (SEM) was recorded to

determine morphological features and Atomic Absorption Spectroscopic analysis was

carried out to determine qualitative analysis of elemental concentration.

3.3.1. XRD technique:

The X-ray diffraction patterns of the FeOOH used in the present work are

shown in Figure3.4. In Figure 3.4, the identification of crystalline phase of FeOOH

was accomplished by comparison with JCPDS file No. 29–0713. On careful

observation XRD pattern, we notice the presence of some additional reflections along

with those corresponding to FeOOH.

Figure.3.4.XRD Pattern of FeOOH

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3.3.2. XRF Analysis:

X-ray fluorescence spectrum was recorded using Minipal- 4 benchtop model,

with fine focus X-ray tube, MO target of multilayer monochromator of 17.5KeV.

Figure.3.5 clearly indicates that the pattern shows the presence the Fe+2

.

Figure.3.5. XRF Spectra of FeOOH

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3.3.3 Scanning Electron Microscopy (SEM):

The surface morphologies of the FeOOH were observed by scanning electron

micrographic images as shown in Figure 3.6. Estimation of the particle size appeared

very difficult because of their extremely small dimension and inherent nature of

agglomeration, which is obvious due to high dipole interactions.

Figure.3.6. SEM image of FeOOH

3.4. Characterization of Municipal Solid Waste (MSW) Sample.

The MSW samples were collected from dumping sites of Mysore. The

characterization of MSW was carried out by using X-ray diffraction (XRD) and X-ray

Fluorescence (XRF) in order to determine the phase and elemental composition.

Subsequently Scanning Electron Microscope (SEM) was recorded to determine

morphological features and Atomic Absorption Spectroscopic analysis was carried

out to determine qualitative analysis of elemental concentration.

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1= Ca(OH)2

2=Hg3=NaCl4=Cd5=Pb

6=Cr

3.4.1. X-Ray Diffraction analysis of MSW

X-ray Diffraction spectra of Municipal Solid Waste (MSW) are shown in

Figure 3.7. The reflection of heavy metal peaks were match through Crystal Impact

software (Match copy right 2003-2014), Bonn, Germany. The diffractogram of MSW

clearly indicate the presence of heavy metal like Cadmium, Copper, Lead, Mercury

and Chromium were present in the sample.

Figure.3.7. XRD pattern of MSW sample

3.4.2 XRF Analysis:

Elemental compositions of MSW samples have been analyzed using the X-ray

fluorescence technique. Figure 3.8 shows the XRF pattern of MSW sample. It was

observed that in MSW samples, concentration levels of all the elements are higher

than the ecological screening values and in case of Fe and Ca concentration is more

when compare to other elements. It is well known that traces of Cu, Zn, Mn, Cr, Mo,

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Co, etc., are very essential for human bodies but higher doses and accumulation of

these elements might cause adverse effects in the body.

Figure.3.8. XRF Spectra of MSW sample

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3.4.3. Scanning Electron Microscopy (SEM):

SEM image of MSW sample is shown in Figure 3.9. The collected material

was taken under the SEM without any treatment. Observing the SEM it looks bit

porous in nature. It is observed that the material looks more coiled and bit clustered

on the surface may due to the presence of high amount of organic materials along

with inorganic and heavy metals.

Figure. 3.9. SEM image of MSW sample

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3.4.4. AAS analysis for MSW:

MSW was analysed for heavy metals by Atomic absorption spectroscopy. The

analysis shows that sample was rich in copper content 1.158 mg/kg compared to other

heavy metals. Metals such as Chromium 0.315 mg/kg and lead 0.257 mg/kg were

found at lower concentrations whereas cadmium and mercury concentration was

found to be 0.001 mg/kg. This study is well match with XRF study. Table 3.1 shows

the concentration of selected five heavy metals concentration.

Table.3.1. Heavy metal concentrations for the MSW samples

Sl.No Heavy Metal Concentration (mg/kg)

1 Cadmium <0.001

2 Copper 1.158

3 Lead 0.257

4 Chromium 0.315

5 Mercury <0.001

3.5. Characterization of Steel Bottom ash (BA) sample.

The Bottom Ash samples were collected from dumping sites of VISL,

Bhadravathi. The characterization of Bottom Ash was carried out by using X-ray

diffraction (XRD) and X-ray Fluorescence (XRF) in order to determine the phase and

elemental composition. Subsequently Scanning Electron Microscope (SEM) was

recorded to determine morphological features and Atomic Absorption Spectroscopic

analysis was carried out to determine qualitative analysis of elemental concentration.

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3.5.1. X-Ray Diffraction analysis of Bottom ash.

The X-ray diffraction pattern of Bottom ash used in the present work is shown

in Figure 3.10. The XRD pattern of Bottom ash represent the presence of Heavy

metals and heavy metals peaks are shown in Figure 3.10. The peaks correspond to

heavy metal match was made through Crystal Impact software (Match copy right

2003-2014), Bonn, Germany. The study of XRD pattern clearly indicates that the

presence Cadmium, Copper, Lead, Mercury and Chromium particles are present in the

sample.

Figure 3.10. XRD Pattern of Bottom ash sample

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3.5.2 XRF Analysis:

Elemental compositions of Bottom ash sample have been analyzed using the

X-ray fluorescence technique as shown in Figure 3.11. The samples were collected

from dumping sites of VISL, Bhadravathi. It was observed that in Bottom ash sample,

presence of Copper, Lead, and Mercury particles.

Figure 3.11. XRF Spectra of Bottom ash sample

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3.5.3 Scanning Electron Microscopy (SEM):

SEM image of Bottom ash sample is shown in figure 3.13. The collected

material was taken under the SEM without any further treatment. The SEM studies

showed that the particles had subrounded to angular shapes. Distinct edges were

visible in angular, bulky particles. The gravel-size particles had shapes varying from

sub rounded to sub angular. Distinct edges were visible in sub angular, bulky

particles. Most of the particles had a high spherical and a solid structure. A

heterogeneous porous structure was also observed on the surface of a few particles.

Figure 3.12. SEM Picture of Bottom ash sample

3.5.4 AAS Analysis for Bottom ash sample:

Bottom ash sample was analysed for heavy metals by using Atomic absorption

spectroscopy, which shows that sample was rich in Chromium 0.427 mg/kg compared

to other heavy metals. Metals such as copper content 0.251 mg/kg and lead 0.041

mg/kg were found at lower concentrations whereas cadmium and mercury

concentration was found to be 0.001 mg/kg. Table 3.2 shows the concentration of

selected five heavy metals concentration.

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Table.3.2. Heavy metal concentration in Bottom ash sample

Sl.No Heavy metals Concentration (mg/kg)

1 Cadmium <0.001

2 Copper 0.251

3 Lead 0.041

4 Chromium 0.427

5 Mercury <0.001