Polluting our waterways makes us our own worst enemies. However, nature is also to fault. Our sources of drinking water are fed by agricultural runoff into rivers and streams. The organic compounds in this runoff have an impact on the water’s cleanliness. The purifying procedure is aided by Ultra-Violet (UV-Visible) spectroscopy. Some of the top civil engineering colleges in Nashik are training students to develop revolutionary technologies like UV spectroscopy in the future.
Measurements of what enters and exits water treatment facilities are required. One effective technique that can make measuring these changes easier is Ultra-Violet (UV-Visible) spectroscopy. These facilities need to monitor the changes in these materials over time as they interact with natural organic organisms in water or physically bind with other particles. When a decaying leaf interacts with runoff, for example, compounds may appear as bacteria. The destiny and movement of these chemicals, regulating their concentration, and observing their by-products are all of interest to scientists.
Large water treatment facilities have analytical labs and many of them are starting to use spectroscopy to identify these changes. The amounts of various chemicals in the water can be determined with the use of Ultra-Violet (UV-Visible) spectroscopy. Later in the course of treatment, undesirable chemicals can be removed.
In addition to monitoring treatment procedures for the removal of organic and particle pollutants, UV-Vis spectroscopy can be used to measure a variety of factors, such as nitrate and total organic carbon (TOC). Furthermore, UV disinfection stops bacteria in water from reproducing by inactivating them with UV light
In the realm of online water-quality monitoring, UV-Vis spectroscopy is becoming more and more recognised as an efficient technique for water quality measurement when compared to more conventional methods. The benefits of UV-Vis spectroscopy are quick reaction times, little maintenance expenses, and the absence of secondary pollutants. The concept of using UV-Vis spectroscopy to analyse water quality is presented in this study. A thorough evaluation of previous studies on the online assessment of water quality using data fusion and UV-Vis spectrum technology is conducted. Additionally covered are the uses of UV-Vis based techniques for water quality categorisation, multi-parameter monitoring, and water quality alarms. Lastly, suggestions for future research are given.
ULTRA VIOLET–VISIBLE (UV) SPECTROSCOPY
UV-Vis spectroscopy is an analytical technique that measures the amount of discrete wavelengths of UV or visible light that are absorbed by or transmitted through a sample in comparison to a reference or blank sample. Thus, shorter wavelengths of light carry more energy and longer wavelengths carry less energy. Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) involves the spectroscopy of photons in the UV-visible region. This means it uses light in the visible and adjacent (near ultraviolet (UV) and near infrared (NIR) ranges.
The absorption in the visible ranges directly affects the colour of the chemicals involved. In this region of the electromagnetic spectrum, molecules undergo electronic transitions. This technique is complementary to fluorescence spectroscopy, in that fluorescence deals with transitions from the excited state to the ground state, while absorption measures transitions from the ground state to the excited state.
UV-Vis spectroscopy refers to measurement of absorption or reflectance in ultra violet, visible and near infra-red (IR) region, as a function of wave-length λ of absorbed/reflected electromagnetic radiation (EMR). Absorption in this region directly affects colours of chemicals and is governed by Beer-Lambert Law. This law states that when a beam of light passed through a transparent cell containing the solution of an absorbing substance, reduction in intensity of light may occur. The instrument used in ultraviolet-visible spectroscopy is called a UV-Vis spectrophotometer.
The instrument used in ultraviolet-visible spectroscopy is called a UV-Vis spectrophotometer. Hitachi U-2800 double beam spectrophotometer is used for investigation. It measures the intensity of light passing through a sample (I), and compares it to the intensity of light before it passes through the sample (Io). The ratio I / Io is called the transmittance, and is usually expressed as a percentage (%T). The absorbance, A, is based on the transmittance.
The basic parts of a spectrophotometer are a light source, a holder for the sample, a diffraction grating or monochromator to separate the different wavelengths of light, and a detector. The radiation source is often a Tungsten filament (300-2500 nm), a deuterium arc lamp which is continuous over the ultraviolet region (190-400 nm), and more recently light emitting diodes (LED) and xenon arc lamps for the visible wavelengths. The detector is typically a photodiode or a CCD. Photodiodes are used with monochromators, which filter the light so that only light of a single wavelength reaches the detector. Diffraction gratings are used with CCDs, which collects light of different wavelengths on different pixels. In a double-beam spectrophotometer, the light is split into two beams before it reaches the sample. One beam is used as the reference; the other beam passes through the sample. Some double-beam instruments have two detectors (photodiodes), and the sample and reference beam are measured at the same time. In other instruments, the two beams pass through a beam chopper, which blocks one beam at a time. The detector alternates between measuring the sample beam and the reference beam.
An ultraviolet-visible spectrum is essentially a graph of light absorbance versus wavelength in a range of ultraviolet or visible regions. Such a spectrum can often be produced directly by a more sophisticated spectrophotometer, or the data can be collected one wavelength at a time by simpler instruments. Wavelength is often represented by the symbol λ. Similarly, for a given substance, a standard graph of the extinction coefficient (ε) versus wavelength (λ) may be made or used if one is already available. Such a standard graph would be effectively & and thus independent of concentration.
The practical implications of using online UV-Vis spectrophotometers for process control and water quality monitoring are covered in this paper, with a focus on industrial applications. The literature has addressed the use of online UV-Vis spectrophotometers for managing the quality of drinking water. Online UV-Vis instruments for drinking water that are often used have been described. The built-in algorithms of the online UV-Vis sensors can be used to directly create water quality parameters such as UV254, color, DOC, turbidity, and nitrate.
Conclusion
There are many advantages to the development of such technologies in the long run. Students pursuing B.Tech Civil Engineering are in a position to innovate and pioneer in such technologies to create a safe and secure environment for global citizens around the world.