Susheel K. Mittal

PVC-based dicyclohexano-18-crown-6 sensor for La(III) ions.

A new ion-selective electrode (ISE) based on dicyclohexano-18-crown-6 (DC18C6) as a neutral carrier is developed for lanthanum(III) ions. The electrode comprises of dicyclohexano-18-crown-6 (6%), PVC (33%), and ortho-nitrophenyl octyl ether (o-NPOE) (61%). The electrode shows a linear dynamic response in the concentration range of 10(-6) to 10(-1)M with a Nernstian slope of 19mV per decade and a detection limit as 5x10(-7)M. It has a response time of <30s and can be used for at least 5 months without any significant divergence in potentials. The selectivity coefficients for mono-, di-, and trivalent cations indicate good selectivity for La(III) ions over a large number of interfering cations. The sensor has been used as an indicator electrode in the potentiometric titrations of La(III) with EDTA. The membrane is successfully applied in partially non-aqueous medium. It can be used in the pH range 4-9.

Toxic effect of metal ions on biochemical oxygen demand

Toxic effect of metal ions like Al, Co, Ni, Cu, Zn, Pb and Hg on the Biochemical Oxygen Demand (BOD) exertion has been studied at various concentrations of the metal ions. Presence of these metal ions in the effluent samples significantly affects the observed BOD values. The magnitude of their dependence varies with the nature and concentration of the metals working as a toxicant. The detrimental effect of metal ions on the observed BOD is a resultant of the biological as well as chemical processes taking place in the sample. Addition of metal ions like Al, Zn, Cu and Pb results in the inhibition as well as increase in BOD. Mechanism for the effect of metal ion on BOD has been proposed and is correlated with their electrochemical potentials.

Effects of agriculture crop residue burning on children and young on PFTs in North West India.

Variations in pulmonary function tests (PFTs) due to agriculture crop residue burning (ACRB) on children between the age group of 10 to 13 years and the young between 20 to 35 years are studied. The effects of exposure to smoke due to rice-wheat crop residue burning on pulmonary functions like Force Vital Capacity (FVC), Force Expiratory Volume in one second (FEV(1)), Peak Expiratory Flow (PEF) and Force Expiratory Flow in 25 to 75% of FVC (FEF(25-75%)) on 40 healthy subjects of rural/agricultural area of Sidhuwal village of Patiala City were investigated for a period from August 2008 to July 2009. Measurements were taken by spirometry according to the American Thoracic Society standards. High volume sampler (HVS) and Anderson Impactor were used to measure the concentration levels of SPM, PM(10) and PM(2.5) in ambient air of the Sidhuwal village. A significant increase in the concentration levels of SPM, PM(10) and PM(2.5) was observed due to which PFTs of the subjects showed a significant decrease in their values, more prominently in the case of children. PFTs of young subjects recovered up to some extent after the completion of burning period but the PFT values of children remained significantly lower (p<0.001) even after the completion of burning episodes. Small size particulate matter (PM(2.5) and PM(10)) affected the PFTs to a large extent in comparison to the large size particulate matter (SPM). The study indicates that ACRB is a serious environmental health hazard and children are more sensitive to air pollution, as ACRB poses some unrecoverable influence on their PFTs.

Modeling Impact of Solar Radiation on Site Selection for Solar PV Power Plants In India

Solar power is gaining importance in the light of discussion about climate change and renewable energy sources. In most parts of India, clear sunny weather is experienced 250–300 days in a year. The annual global radiation varies from 1600 to 2200 kWh/m2, which is comparable with radiation received in the tropical and subtropical regions. This paper runs simulation scenarios for various sites in India for technical and financial viability of solar power generation with photo voltaic (PV) technology. Solar radiation data are accessed from National Aeronautics and Space Administration (NASA) website, and other meteorological parameters are collected from Indian Meteorological Department (IMD). The data are fed into RETScreen model to run various simulation scenarios. Feasibility of sites in India to build a 5-MW PV-grid connected power plant from techno-economical and environmental points of view are discussed. A model is run for 31 major sites in India to measure the viability of Solar PV plants at these sites. Financial incentives announced in national solar mission of India have been used as an input to the model. Viability indicators like internal rate of return (IRR), net present value (NPV), cost of electricity (CoE), benefit–cost (B–C) ratio are identified on the basis of the model. A comparison of results is done and the best sites in India are reported.

Viologen substituted anthrone derivatives for selective detection of cyanide ions using voltammetry

Electrochemical behavior of anthrone derivatives 1 (1-(2,7-dioxo-3,7-dihydro-2H-naphtho[1,2,3 de]quinolin-1-yl)-1′-heptyl-4,4′-bipyridine-1,1′-diium) and 2 (1-(2,7-dioxo-3,7-dihydro-2H-naphtho[1,2,3-de]quinolin-1-yl)-[4,4′-bipyridine]-1-ium functionalized with viologen group are inspected extensively using cyclic voltammetry. Colorimetric studies indicate their selectivity towards anions like cyanide, acetate and fluoride. Cation selectivity of anthrone derivative changes to anions because of the viologen group. Anthrone derivative stabilizes viologen through conjugation, reducing one of its two redox couples which are characteristic of viologen group for molecule 1. Mechanisms are proposed and supported by theoretical studies carried out using Guassian 03W for the electrochemical behaviour of compounds 1 and 2. Voltammograms of dicationic viologen derivative 1 show near quenching of anodic peaks (a decrease of almost 90% of current) as well as cathodic peaks (a decrease of almost 100% current) in the presence of 1 equivalent of cyanide ions. The molecule 2 undergoes quenching of the cathodic peak while anodic peak survives in the presence of the anions, cyanide, acetate and fluoride. The proposed electrochemical sensors are selective for CN−, OAc− and F− based on binding constants which are much larger than for anions like Cl−, Br−, I−, HSO4−. The proposed voltammetric method for the cyanide determination is compared with potentiometric and spectrophotometric methods for cyanide determination. The proposed voltammetric method has also been used for quantitative determination of cyanide in unknown samples.

Effects of air pollution on respiratory parameters during the wheat-residue burning in Patiala.

Effects of pollution produced by wheat-residue burning on respiratory parameters of healthy inhabitants were investigated for two consecutive wheat cultivation periods (February–July in 2007 and 2008) at Patiala city of Punjab, India. A total of 51 selected subjects of the age group 13–53 were selected from five sites of Patiala for pulmonary function tests (PFTs), including force vital capacity (FVC), force expiratory volume in one second (FEV1), peak expiratory flow (PEF) and force expiratory flow between 25 to 75% of FVC (FEF25–75%) using a spirometer. High volume samplers (HVS) and an Andersen cascade impactor were also used to measure the concentration of suspended particulate matter (SPM) and particulate matter (PM) of size less than 10 μm. PFTs show significant decrease and particulate matter shows a significant increase during the burning period of wheat residue. Decrease in FVC and FEV1 did not recover even after completion of the exhaustive burning period this is a more serious concern then PEF and FEF25–75%. The results showed that the public exposure to relatively high levels of pollutants during the exhaustive burning period of wheat residue influences the PFTs of even healthy inhabitants.

Effects of exposure to rice-crop residue burning smoke on pulmonary functions and Oxygen Saturation level of human beings in Patiala (India)

Pulmonary Function Tests (PFTs) like Force Vital Capacity (FVC), Force Expiratory Volume in one second (FEV₁), Peak Expiratory Flow (PEF) and Force Expiratory Flow between 25 and 75% of FVC (FEF(25-75%)) and Oxygen Saturation (SpO₂) level of 50 healthy inhabitants with respect to rice crop residue burning were investigated for three rice cultivation periods from 2007 to 2009. The subjects were residents of five sampling sites selected in Patiala city. Concentration of Suspended Particulate Matter (SPM), Sulfur dioxide (SO₂), Nitrogen dioxide (NO₂) and Particulate Matter (PM) of size less than 10 and 2.5 μm (PM₁₀ and PM₂.₅) were measured by using High Volume Sampler (HVS) and Cascade Anderson Impactor. Results show that rice crop residue burning increases the pollution level in the ambient air, and PFTs undergo a significant decrease in their respective values. No significant change was seen in SpO₂ level during rice crop residue burning. In 2008, an increase of 10 μg m⁻³ in PM₂.₅, PM₁₀, SPM and NO₂ was associated significantly with decrease in FVC in percentages predicted -1.541, -1.002, -1.178, -0.232%, respectively. The decrease in air quality due to open rice crop residue burning has sub acute effect on pulmonary functions of healthy subjects and that SO₂ and NO₂ have less adverse effects on pulmonary functions than with different size Particulate Matter.

Fabrication of a mercury(II) ion selective electrode based on poly-o-toluidine–zirconium phosphoborate

This work covers various aspects of a new ion selective electrode for mercury(II) ions, designed by incorporation of poly-o-toluidine (PTD) into zirconium phosphoborate (ZrPB) ion exchanger. The designed sensor showed pretty good detection ability towards Hg2+ ions in comparison to alkali, alkaline earth, transition and even some heavy metal ions. The crystallinity and morphology of the synthesized composite has been explored using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. A linear near Nernstian response for Hg(II) ions with a slope of 28.0 mV per decade over a wide concentration range (1 × 10−7 M to 1 × 10−1 M) has been observed. The limit of detection is 7.08 × 10−8 M (0.014 ppm). Moreover, the electrode showed significantly the same results in the pH range 2.5–10.0, a fast response time of 6 s and a life-time of at least 6 months without any divergence in potential. It has been successfully applied as an indicator electrode in potentiometric titrations, and quantitative estimation of Hg(II) ions in tap water, CFL unit waste water and thermometer unit waste.

Cerium(III)-Selective Membrane Electrode Based on Dibenzo-24-crown-8 as a Neutral Carrier

Cerium(III)-selective membrane electrodes have been prepared using dibenzo-24-crown-8 (DB24C8) as an electroactive material. A membrane having a composition: DB24C8 (4.5%), plasticizer (NPOE, 62.5%) and PVC (33%) gives the best performance. It works well over a wide Ce(III) ion-concentration range of 1x10-5 M to 1x10-1 M with a Nernstian slope of 19.0 mV/decade and a detection limit of 3x10-5 M. It has a fast response time of 20 seconds and has an average lifetime of four months. The internal solution concentration does not have a significant effect on the response of the electrode except for a change in intercept of the calibration curves. The working pH range for Ce(III) solutions (1x10-2 M and 1x10-3 M) is 3.5-8.0. The proposed sensor shows a good selectivity for cerium(III) with respect to alkali, alkaline earth, some transition and rare earth metal ions that are normally present along with cerium in its ores. The proposed sensor was investigated in partially non-aqueous media using acetone, methanol and DMSO mixtures with water. The electrode was further used as an indicator electrode for the potentiometric titration of Ce(III) solution against oxalic acid solution.

Impact of rice crop residue burning on levels of SPM, SO2 and NO2 in the ambient air of Patiala (India)

Ground-based ambient air monitoring was conducted at five different locations in and around Patiala city (29°49′–30°47′N Latitude, 75°58′–76°54′E Longitude) in Northern India in order to determine the impact of open burning of rice (Oriza sativa) crop residues on concentration levels of suspended particulate matter (SPM), sulphur dioxide (SO2) and nitrogen dioxide (NO2). Covering sensitive, residential, agricultural, commercial and urban areas, sampling of these pollutants was organised during August 2006 to January 2007 and August 2007 to January 2008 casing two rice crop residue burning periods (October–November) using a high volume sampling technique combined with gaseous sampling systems. Gravimetric analysis was used in the estimation of total suspended particulate matter (TSPM) whereas SO2 and NO2 concentration was determined using spectrophotometer (Specord205, Analytikjena). Monthly average concentrations of SPM, SO2 and NO2 have shown significant up and down features at all the selected sampling sites during the study period. Monthly average concentrations (24 hour) of SPM, SO2 and NO2 varied from 100 ± 11 µg m−3 to 547 ± 152 µg m−3, 5 ± 4 µg m−3 to 55 ± 34 µg m−3 and 9 ± 5 µg m−3 to 91 ± 39 µg m−3. Substantially higher concentrations were recorded at the commercial area site as compared to the other sampling sites for all the targeted air pollutants. Levels of SPM, SO2 and NO2 showed clear increase during the burning months (October–November) incorporated with the effect of meteorological parameters especially wind direction, precipitation and atmospheric temperature.