Dr. Amrita Thakur

Mercury, one of the common pollutants in water, is known to affect human health adversely upon exposure. It is released in water not only by various natural processes but also by human activities. Methods developed so far for the detection of mercuric ions in water have limitations like sensitivity range, complex setup, skillful operation etc. Silver nanoparticles, due to unique properties, have been explored by researchers to develop better detection systems. Stable silver nanoparticles can be easily synthesized by methods of green chemistry, its reaction with mercuric ion can be easily observed by changes in color and UV-Vis spectra. The absorbance data from UV-Vis spectra can also be used in quantifying mercury concentration. In this paper, stable silver nanoparticles synthesized using silver nitrate as precursor, sodium lignosulphonate (LS) as reducing and stabilizing agent under microwave radiation are explored for detection of mercuric ions in water. Formation of Ag nanoparticles was confirmed by UV-Vis band at 403.5nm. The intensity of this band showed a proportional decrease with increasing Hg+2 concentration. Hg+2 ions were detected by a distinct color change at higher concentration of Hg+2 also. The limit of detection (LOD) calculated from the observed absorbance data to be 0.7 ppm.

Biodegradable polymer blends are prepared by solution casting method by mixing Sodium alginate (SA) and Lignosulphonic acid (LS) biodegradable polymers. In order to investigate for controlled drug delivery the thermal stability of polymer blends are the primary requirements because they should be stable in aqueous medium. The polymer blends are studied using thermogravimetric analysis. The TGA data are used to analyze degradation temperature and energy of activation using ‘Horowitz and Metzger’ an approximate integral method. The energy of activation reveals that blends are stable as compared to their polymers.

This work is aimed at developing hydrogel of sodium alginate (SA) with properties suitable for controlled release applications. The hydrogel was synthesized by blending SA with Lignosulphonic acid (LS) stabilized silver nanoparticles. Its characterization was done by UV-vis spectroscopy, FTIR, XRD and TGA techniques. A single peak at 405.2 nm of UV-visible spectra confirmed presence of monodispersed and spherical silver nanoparticles (SNP), stabilization of SNP by LS was confirmed from FTIR and crystallinity by XRD. Beads from drug loaded hydrogel showed sustained release of both drug and silver nanoparticles in pH 7. It was also observed that the silver nanoparticle loaded hydrogel bead showed better stability and drug release ability than SA/LS hydrogel beads. The synthesized hydrogel can be investigated further with other antibiotics for synergistic applications against pathogens.

Air pollution control measures in India are still in its infancy, while the country is developing at a faster rate. Development is known to affect the air quality of a place adversely. The key to manage the air quality of a place is proper planning, and for that, robust forecasting system based on continuous monitoring is required. Bengaluru is a city which has grown in size and population in the past decades. This rapid growth has affected its environmental quality. The present work deals with development of air quality prediction model based on Autoregressive Integrated Moving Average (ARIMA). For this, pollution data of NO2, PM10 and SO2 from January 2013 to March 2016, 14 pollution monitoring stations has been used. The results show that data which satisfies the stationary condition can be used as an accurate prediction model. NO2 residential and RSPM residential satisfy this condition. © Springer Nature Singapore Pte Ltd. 2018.

Presence of certain substances in air adversely affects human health, environment and climate. These chemicals are mainly added due to human activities. Maintaining air quality requires regular monitoring, identification of source of pollution and adoption of preventive measure. Bangalore a city in India has grown in size and population recently due to growth of IT industry. This rapid growth and related civic activity has affected its ecological services. The objective of this study is to identify air pollution trend in Bangalore and investigate the factors contributing towards it. Data for analysis has been obtained from state pollution control board website and has been used without any modification. Three criteria pollutants measured regularly and for longest period of time, sulphur dioxide (SO2), nitrogen dioxide (NO2) and respirable particulate matter (PM10) have been investigated for air quality analysis.

Blends of sodium alginate (SA) and lignosulphonic acid (LS) has been prepared in the ratio of 80/20. The prepared blends were crosslinked using chlorides of calcium, barium, strontium and aluminum. The crosslinking of blends was done for different time intervals and then these blends were subjected for swelling studies in aqueous medium of pH 7.4. The observations indicate that the crosslinking is diffusion controlled and is affected by the size of metal ion and the type of alginate used. The improved swelling time for crosslinked blends in aqueous medium supports the fact that the stability under physiological conditions of the blends is improved due to crosslinking with the metal ions. Calcium chloride and barium chloride forms strong crosslink with the blend. Calcium ion crosslinked blends can be considered suitable for biomedical drug applications. The investigations on crosslinked blends using FTIR, SEM, XRD and EDAX are in close agreement with swelling results.

A bidentate nitrogen/ oxygen containing Schiff base ligand, 3-amino-2-methyl quinazoline-4(3H)hydrazone (AMQH) and its Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized by molar mass, elemental analyses, spectral (IR and electronic) molar conductivity measurements at the room temperature. On the basis of above spectral and physicochemical studies it is proposed that ligand 3-amino-2-methyl quinazoline-4(3H)hydrazone acts in a bidentate manner and coordination proposes through amino group of quinazoline and azomethine N atom. The remaining coordination of metal ions are satisfied by negative ions such as Cl-, Br-, I- and NO3-. The electronic spectral data proposes an octahedral geometry for Ni(II) and Co(II) while the geometry of Cu(II) complexes are proposed to be distorted octahedral in nature.

Condensation of 1-phenyl-1,2-proparndione-2-oxime with 1,2-diaminobenzene in an ethanolic medium yields a Schiff base ligand, bis-(1-phenyl-2-hydroxyimino-1-propylidene) 1,2-diaminobenzene, H2L. A number of complexes of the types [ML] [M = Co(II), Ni(II), Cu(II}], [M(H2L)X2] [M = Co(II), Ni(II), X = Cl–, Br–, I–, ClO–4, NO–3] and [Cu2LX2] [X = Cl–, Br–, I–, ClO–4, NO–3] have been synthesized and characterized on the basis of their elemental analyses, magnetic moment, infrared and electronic spectral data as well as conductivity measurements where the ligand behaves as a tetradentate ligand in the first two series and in a hexadentate manner in the third one.

A simple method based on the principles of green chemistry has been developed to synthesize stable silver nanoparticles (AgNP) for possible biomedical applications. Blend of sodium alginate (SA) and lignosulphonic acid (LS) prepared in the ratio of 80/20 mass percent respectively was used as reducing and stabilizing agent. This blend is biocompatible and has shown drug release ability under physiological conditions. Use of blend has an added advantage as LS has the ability to reduce silver while the blend matrix acts as a stabilizing agent. Effect of precursor concentration (AgNO3) and temperature was investigated. Progress of synthesis was monitored using UV-Vis spectroscopy. Higher temperature and lower silver nitrate concentration showed better synthesis of AgNP.