Chapter -3 RESULTS AND DISCSSION

Transcription

1 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 Fe 2 O 3. 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 (Fe 3 O 4 ), which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe 2 O 3 is the main source of the iron for the steel industry. Fe 2 O 3 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. 56

2 INTENSITY 3.2 Characterization of Fe 2 O 3 : The characterization of Fe 2 O 3 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 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 Fe 2 O 3 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 Fe 2 O 3 (JCPDS file No ), having rhombohedral structure. On careful observation XRD pattern, we notice the presence of some additional reflections along with those corresponding to Fe 2 O Fe 2 O 3 Fe 2 O θ Figure.3.1. XRD Pattern of Fe 2 O 3 57

3 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 Fe 2 O 3 clearly indicate that the presence of Fe +3 (Figure 3.2). Figure.3.2. XRF Spectra of Fe 2 O 3 58

4 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 Fe 2 O 3 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 Fe 2 O 3 59

5 INTENSITY 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 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 On careful observation XRD pattern, we notice the presence of some additional reflections along with those corresponding to FeOOH FeOOH FeOOH θ Figure.3.4.XRD Pattern of FeOOH 60

6 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 61

7 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. 62

8 INTENSITY 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 ), 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 = Ca(OH) 2 2=Hg 3=NaCl 4=Cd 5=Pb 6=Cr θ Figure.3.7. XRD pattern of MSW sample 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, 63

9 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 64

10 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 SEM image of MSW sample 65

11 AAS analysis for MSW: MSW was analysed for heavy metals by Atomic absorption spectroscopy. The analysis shows that sample was rich in copper content mg/kg compared to other heavy metals. Metals such as Chromium mg/kg and lead mg/kg were found at lower concentrations whereas cadmium and mercury concentration was found to be 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 < Copper Lead Chromium Mercury < 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. 66

12 INTENSITY X-Ray Diffraction analysis of Bottom ash. The X-ray diffraction pattern of Bottom ash used in the present work is shown in Figure The XRD pattern of Bottom ash represent the presence of Heavy metals and heavy metals peaks are shown in Figure The peaks correspond to heavy metal match was made through Crystal Impact software (Match copy right ), Bonn, Germany. The study of XRD pattern clearly indicates that the presence Cadmium, Copper, Lead, Mercury and Chromium particles are present in the sample =Fe 2=Ca 3=Mn 4=Cu 5=Hg 6=Si θ Figure XRD Pattern of Bottom ash sample 67

13 3.5.2 XRF Analysis: Elemental compositions of Bottom ash sample have been analyzed using the X-ray fluorescence technique as shown in Figure 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 XRF Spectra of Bottom ash sample 68

14 3.5.3 Scanning Electron Microscopy (SEM): SEM image of Bottom ash sample is shown in figure 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 SEM Picture of Bottom ash sample 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 mg/kg compared to other heavy metals. Metals such as copper content mg/kg and lead mg/kg were found at lower concentrations whereas cadmium and mercury concentration was found to be mg/kg. Table 3.2 shows the concentration of selected five heavy metals concentration. 69

15 Table.3.2. Heavy metal concentration in Bottom ash sample Sl.No Heavy metals Concentration (mg/kg) 1 Cadmium < Copper Lead Chromium Mercury <