Characterization of Surface water components In Northern Sudan Using Raman Spectroscopy

The Most population in northern Sudan are supplied by surface water sources directly from the Nile for drinking and irrigation purposes. As noted, most of them suffer from chronic diseases such as cancer and kidney failure. Water is expected to be a major and direct cause of these diseases, so the aim of this study is to identify the components of surface water in northern Sudan using Raman spectroscopy. Surface water Samples were collected from the Nile in different regions. The samples were analyzed at room temperature by Nd-YAG Laser 532 nm with 6 mW. Model Horiba Lab RAM HR D3 Raman spectrometer. The results showed that the samples contain different materials, beside the water, with different amounts; like: aromatic molecules, ester, salts, amides, phenol, alkynes and acids.

Published by || IJCSMR Journal their habitats. Providing sufficient quantities of good quality water is a major factor in creating the life style we enjoy in Sudan. Surface water is the term used to describe water on the land surface. The water may be flowing, as in streams and rivers, or quiescent, as in lakes, reservoirs, and ponds. Surface water is produced by runoff of precipitation and natural groundwater seepage. [2] 1.1 aman spectroscopy Principles: Raman spectroscopy is a spectroscopic technique based on inelastic scattering of monochromatic light, usually from a laser source. [3] The dominant in Raman scattering is Rayleigh and the very small amount of Raman scattered light. The induced dipole moment occurs as a result of the molecular polarizability, where the polarizability is the change and deformability of the electron cloud about the molecule by an external radiation.
A very small amount of Raman scattered are Stokes and anti-Stokes. Molecules initially in the ground vibrational state (m) excited to virtual states, then return back to vibrational excited state (n) give rise to Stokes Raman scattering ( ) molecules initially in vibrational excited state (n) excited to virtual states, then return back to ground vibrational state (m) give rise to anti-Stokes Raman scattering ( ). The intensity ratio of the Stokes relative to the anti-Stokes Raman bands is governed by the absolute temperature of the sample, and the energy difference between the ground and excited vibrational states. The Stokes Raman lines are much more intense than anti-Stokes, since at ambient temperature most molecules are found in the ground state. Figure 1 describes Raman Effect. [4]

Fig.1. the diagram the energy diagram of a molecule showing the origin of Raman scattering.
Raman spectroscopy as a vibrational spectroscopy technique, has gained more interest and powerful in research especially in identification and characterization of materials. Through specific spectral patterns, substances can be identified and molecular changes can be observed with high specificity. In addition, it is easy to use and need no sample preparation [5] 2. Materials and Methods: 2.1 Materials: Surface water samples were collected from five regions in northern Sudan (Halfa, Abry, Abuhamad, Atbra and Shandy). Each sample was put in the glass substrate of the spectrometer and Raman spectrum was recorded in the region from 300 to 2800 . The Raman shift in wavenumber, and the change in intensities of the scattered light in Raman spectra were compared with data in the previous studies and references.

Instrumentation:
Laser Raman microscope spectrometer model Horiba Lab RAM HR D3, shown in the Figure2 was used. The light source of this spectrometer is Nd-YAG Laser with wavelength of 532 nm and output power of 6mW.

Results and discussion:
The Raman spectrum of a sample taken from the Nile in the area of Halfa in the range from 389 to 2403 as figure 3 shows. it shows clear peaks and by comparison with the vibrations recorded in some references, we found that these vibrations describe the vibrations of water molecules and some components of other materials as listed in Table 1. Published by || IJCSMR Journal   The water sample which taken from the Nile in Abuhamad area, clear picture of the water components and some other materials as in figure 5 and Table 3 illustrates the analysis of this spectrum.   Fig.6 Table 4.   Published by || IJCSMR Journal After the analysis of the samples we found that, the vibration modes of some materials appeared in all samples while some of them appeared in some samples and disappear in others.

shows the Raman spectrum of the sample collected from the Nile in the Atbra area. beside the vibrations of water molecules some other vibrations were appeared in the spectrum. As shown in
Published by || IJCSMR Journal 9.
(C-C) stretching observed in the spectra of samples ( Halfa, Abry and Shandy) with intensities (13.87, 20.12 and 7.88) respectively. 10. Lactone with intensities (14.45, 14.46 and 11.26) appeared in the spectra of samples (Halfa, Abuhamad and Shandy) respectively. 11. CO stretch and strong ring-H and COH rocking motions with intensities (18.05, 11.20 and 11.16)  appearedin the spectra of sample Shandy with intensity (9.99) 27. C-N-C and Ethylbenzene appeared in the spectra of sample Atbra with intensities (7.88 and 11.89) respectively.

Conclusions:
Raman Spectroscopy is one of the best techniques that can be used to identify the surface water components .
And it provides precise information about other materials found in the samples. The Raman spectra intensity of molecules is directly proportional to its concentration. It is very easy to quantitatively calculate the molar concentrations of components in water.

Acknowledgements:
We wish to thank the Institute of Laser in Sudan for supporting this research and Indian Institute of Science for recording the Raman spectra.