Department of Physics

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Assessment of Water Quality Parameters in Real-Time Environment
(Springer, 2020-10) Gupta, Raj Kumar; Gupta, Karunesh Kumar
Assessment of drinking water quality has been an important issue nowadays as the water available is severely polluted and can be the cause of diseases like cholera, diarrhea, dysentery, etc. The traditional methods for water quality monitoring require a high-labor-cost and tine consumption as these methods include a sample collection followed by lab-based chemical testing. In addition, the chemicals used in the testing are toxic and of high-cost. So, there is a need for real-time monitoring and chemical-free testing of water quality parameters. This paper presents a real-time water quality monitoring system based on the Raspberry Pi 3 development board and a Python framework. The water quality parameters utilized for water quality monitoring are temperature, pH, oxidation reduction potential, electrical conductivity, and dissolved oxygen and E. coli. The water quality sensors were interfaced with the designed embedded platform. Finally, the acquired parameters were compared with the benchmark equipment for validation.
Detection of cadmium ion in aqueous medium by simultaneous measurement of piezoelectric and electrochemical responses
(Elsevier, 2018-09) Manjuladevi, V.; Gupta, Raj Kumar; Gupta, Karunesh Kumar
Cadmium is one of the important heavy metals which poses health hazards due to its consumption through potable water. Cadmium is known to form complexes with amine group and also it has good affinity towards carbon nanotubes. The octadecylamine functionalized single-walled carbon nanotubes (ODACNTs) can be employed for sensing cadmium ion in aqueous medium. A thin film of ODACNTs offers not only strong adsorption properties towards cadmium ion but also provides an enormous gain in surface to volume ratio, and good mechanical and chemical stability. Therefore, a sensing layer of ODACNTs was formed on the gold deposited quartz wafer and the sensing towards cadmium ion in the aqueous medium was performed. An experimental setup was designed to record the electrochemical and piezo-responses simultaneously. The piezo and electrochemical responses were found to be linear in the given concentration range. Interestingly, the piezoresponse modulates systematically and repeatedly from a maximum to minimum value due to voltage sweep during cyclic voltammetry indicating the interfacial phenomenon of adsorption and desorption.
Heavy Metal Ion Sensing Using Ultrathin Langmuir–Schaefer Film of Tetraphenylporphyrin Molecule
(IEEE, 2019-12) Manjuladevi, V.; Gupta, Karunesh Kumar; Kumar, Dalip; Gupta, Raj Kumar
The exciting properties of porphyrin molecules can be employed for several applications like sensing, catalysis, photovoltaics and energy related fields. The assemblies of the molecules at interfaces can give rise to some unique physicochemical properties which can enhance the device performance. In this article, we report our studies on heavy metal ion sensing in aqueous medium using ultrathin film of tetraphenylporphyrin (TPP) molecules. The TPP molecules were synthesized and used for forming Langmuir monolayer at the air-water interface. The monolayer was transferred onto solid substrates by Langmuir-Schaefer (LS) method at different target surface pressure of deposition (πT). The morphological analysis of the films indicated supramolecular assembly of the molecules in the LS film deposited at πT = 30 mN/m. The LS films of TPP molecules were employed for sensing heavy metal cations viz. Pb 2+ , Hg 2+ , Co 2+ and Cd 2+ from the aqueous medium by measuring piezoresponse from a quartz crystal microbalance. The sensing performance was found to be the best with LS film deposited at πT = 30 mN/m. The sensitivity-towards Pb 2+ ion is found to be the highest. The sensing of the heavy metal cations using randomly oriented TPP molecules in spin coated thin film was found to be much inferior as compared to that of LS films of the molecule. The enhanced sensing performance by the LS film of TPP molecules may be attributed to the supramolecular assembly of the molecules. We report that the interference of the sensing measurement for the recognition of Cd 2+ and Pb 2+ ions is least and thus these species can be detected selectively with less errors. The cation species recognition features obtained from scanning electron microscope images and Raman spectroscopy were found to be remarkably different and therefore these cationic heavy metal species can be selectively detected using the LS film of TPP.
Raspberry Pi-based smart sensing platform for drinking-water quality monitoring system: a Python framework approach
(Copernicus Publication, 2019) Gupta, Raj Kumar; Gupta, Karunesh Kumar
This paper proposes the development of a Raspberry Pi-based hardware platform for drinking-water quality monitoring. The selection of water quality parameters was made based on guidelines of the Central Pollution and Control Board (CPCB), New Delhi, India. A graphical user interface (GUI) was developed for providing an interactive human machine interface to the end user for ease of operation. The Python programming language was used for GUI development, data acquisition, and data analysis. Fuzzy computing techniques were employed for decision-making to categorize the water quality in different classes like “bad”, “poor”, “satisfactory”, “good”, and “excellent”. The system has been tested for various water samples from eight different locations, and the water quality was observed as being good, satisfactory, and poor for the measured water samples. Finally, the obtained results were compared with the benchmark for authentication.
Real-time water quality monitoring for distribution networks in IoT environment
(Inder Science, 2022) Gupta, Raj Kumar; Gupta, Karunesh Kumar
Water quality has always been a significant concern worldwide as a large portion of accessible water is either contaminated or polluted, which can spread serious diseases like dysentery, diarrhoea and cholera. Before consumption, the water quality should be tested to reduce the risk of infection. In real-time applications, the traditional approach for water quality monitoring is not appropriate, as on-site water sample collection is often a cost-intensive and time-consuming process. This paper introduces a real-time assessment of water quality parameters in distribution systems employing Raspberry Pi and Arduino development boards. The parameters were chosen based on the different categories identified by the Central Pollution and Control Board, Government of India. An Arduino development board was used at the sensing node for water quality sensor interfacing, data acquisition, and transmission to the wireless sensor network via Zigbee. Raspberry Pi was used at the server to collect data and upload data on the cloud platform. The 'Thingspeak' cloud platform was used for IoT implementation. The results were validated with the reference instrument.
A Review of Partial Least Squares Modeling (PLSM) for Water Quality Analysis
(Springer, 2020-10) Gupta, Raj Kumar; Gupta, Karunesh Kumar
Regression is a powerful tool in statistical modeling suited for qualitative and quantitative analysis and widely used in forecasting and prediction. The partial least squares modeling (PLSM) is one of the regression tools used in statistical analysis. There are many fields in which PLSM has been used; water is one of them, which is an area of interest for many researchers and scientists for more than two decades. Since water has multiple parameters to analyze, there is a problem of dimensionality and collinearity. The problem of multidimensionality, as well as collinearity, can be solved by PLSM. PLS regression can be suitable for analysis as it is the most prominent multivariate regression tool. This paper describes the use of PLS regression modeling for water quality analysis of different kinds of water samples (groundwater, wastewater, river water, and coastal water). Various methods employing PLSM for water quality analysis has been discussed in detail.
Selective fluoride ion sensing in aqueous medium using ultrathin film of functionalized single-walled carbon nanotubes
(IOP, 2023-12) Gupta, Raj Kumar; Gupta, Karunesh Kumar; Manjuladevi, V.
The presence of fluoride ion (F-) in potable water above its permissible limit (1–4 ppm) poses serious health hazards. Hence, detection of fluoride in potable water is essential. The π-electron rich single-walled carbon nanotubes can interact with F- to form semi-covalent C-F bond which can act as a basis for F- sensing in aqueous medium. Here, a single layer of octadecylamine functionalized single-walled carbon nanotubes (ODA-SWCNTs) was transferred onto solid substrates by the Langmuir–Schaefer (LS) method and employed for sensing of F- in aqueous medium by recording piezo and electrochemical responses, simultaneously using an electrochemical quartz crystal microbalance. The lowest detectable concentration and range of detectable concentration of fluoride ion were found to be 0.5 ppm and 0.5–145 ppm, respectively. The analysis of the LS film of ODA-SWCNTs before and after interaction with fluoride ion by Raman spectroscopy and grazing angle x-ray diffraction measurement reveals perturbation of π-electrons of the SWCNTs due to semi-covalent binding of the fluoride with the carbon atom of the nanotubes. The sensor showed a good selectivity towards the F- in the presence of some heavy metal ions. Testing of the sensor towards F- in tap water obtained from some local region showed a good accuracy.
Smart Water Quality Monitoring System for Distribution Networks
(SSRN, 2019-06) Gupta, Raj Kumar; Gupta, Karunesh Kumar
Drinking water quality monitoring is essential these days as the available water is polluted and can cause several diseases like cholera, diarrhea, dysentery, etc. This paper presents a low-cost wireless water quality monitoring system based on Arduino and Zigbee Module. Water quality parameters for monitoring is decided by the Central Pollution and Control Board, New Delhi, India. The water quality sensors are interfaced with the Arduino board through signal conditioning circuit. Acquired data is sent to the server over the wireless network through the Zigbee module. At the server, Raspberry Pi is used for data receiving and results have been shown on the graphical display.
Towards the Green Analytics: Design and Development of Sustainable Drinking Water Quality Monitoring System for Shekhawati Region in Rajasthan
(Springer, 2021-05) Gupta, Raj Kumar; Gupta, Karunesh Kumar
In rural areas, there is limited monitoring of drinking water quality. Reliable water quality monitoring stations are expensive and require high costs for maintenance and calibration process. In this paper, the development of a sustainable water quality monitoring system is proposed. The green analytics principles were considered for developing the proposed system to reduce the measurement’s time consumption and labor cost. Five water quality parameters [pH, oxidation reduction potential (ORP), dissolved oxygen (DO), electrical conductivity (EC), and temperature] have been measured using the developed system. The overall drinking water quality is measured by the proposed partial least squares regression (PLSR) model. The developed system’s performance is determined by mean average percentage error (MAPE), root-mean-square error (RMSE), and R2. The traceability of water quality sensors is defined with required uncertainty in water quality parameters. The measured uncertainty is 0.002, 0.892, 0.015, 0.029, and 0.017 for pH, EC, DO, ORP, and temperature, respectively. The relation between estimated and predicted water quality parameters (R2 > 0.93) shows that the developed system can be a suitable replacement for traditional water quality monitoring techniques.