Papers by Keyword: UV-Visible Spectroscopy

Abstract: This paper explores the photocatalytic degradation of methyl orange (MO) dye using Mg doped ZnS nanoparticles, synthesized through a microwave assisted solvothermal method using zinc acetate, magnesium chloride, and thioacetamide. The x-ray diffraction (XRD) analysis confirmed the crystalline structure of the synthesized nanoparticles, indicating their suitability for photocatalytic applications. The optical absorption spectra revealed characteristic peaks in the UV-visible range, correlating with the nanoparticle’s effective light absorption capabilities. Furthermore, the energy bandgap, determined through Tauc plots, highlighted the material's potential for visible light induced photocatalysis, making it an efficient catalyst for dye degradation. Furthermore, the experiment involved preparing an aqueous MO solution, mixing it with Mg doped ZnS nanoparticles, and exposing it to visible light. The changes in the dye were observed using UV-Visible spectroscopy. This method showed that the nanoparticles effectively helped in degrading the dye up to 78.5%. The results indicate that Mg doped ZnS nanoparticles are effective for wastewater treatment, as they can effectively break down harmful dyes and can reduce environmental hazards, providing a sustainable and efficient method to treat industrial wastewater and ensure that released water is safer for the environment.

Abstract: A semi-organic single crystal of potassium hydrogen phthalate (KHP, K(C₆H₄COOH.COO)) doped with Nickel Chloride (NiCl₂) and Glycine (C₂H₅NO₂) was successfully harvested at room temperature to enhance the characteristics of KHP using a slow evaporation approach. The concentration of 1 mol % of Nickel Chloride and 6 mol % Glycine was used during the fabrication of the Nickel Chloride and Glycine doped KHP single crystal. Powder X-Ray diffraction (XRD), ultraviolet visible spectroscopy (UV-Vis), and Fourier transform Infrared (FTIR) analysis were used to analyze the grown single crystal. Powder XRD investigation verified an orthorhombic crystal structure and lattice parameter .To evaluate optical energy band gap and optical transparency using UV-Vis spectral. According to, FTIR analysis, and dielectric studies, it is evident that the crystal modification noticeably by adding dopant.

Abstract: Pure and nickel-doped cadmium sulphide (Ni_xCd_1-xS where x= 2.5%, 5%, 7.5%) nanostructure thin films were successfully prepared by spray pyrolysis method on glass substrate at 350 °C. The films characterized using X-ray crystallography diffractmeter, Scanning Electron Microscope, Atomic Force Microscope and Uv-visible analysis in order to explore the properties of thin film. Structural studies revealed that the deposited films exhibit hexagonal structure with strong intensity at (002) plane. Structural parameters such as crystallite size, strain and dislocation density were calculated for films with different doping concentration. AFM measurements showed that the average diameter increased with increasing Ni doping, where surface roughness and root mean sequre decreased with increasing Ni doping, SEM images show that thin film have been grown and converted into nanowire with increasing of Ni content.Finally, Uv-visible analysis show that the optical band gap of CdS decreased from 2.44 to 2.38 eV with increasing of Ni doping concentrations.

Abstract: Abstract. In this paper we report the biological synthesis of gold nanoparticles (GNPs) by the reduction of gold ions using a suspension and supernatant of P. aeruginosa. The biosynthesis method was straightforward and yielded good results without using toxic chemicals. The size distribution of the gold nanoparticles synthesized by P. aeruginosa at higher temperatures was larger than that synthesized at lower temperatures. The GNPs morphology was isotropic at various temperatures. With an increase in the temperature, the stability of the GNPs decreased. The absorption and fluorescence spectra accorded well with the size distribution of the particles, with the nanoparticle size increasing as the absorption and fluorescence increased too. The optical properties of the GNPs observed in the study accorded well with the scanning electron microscopy (SEM) observations. The visible photoluminescence (PL) around 435 nm indicated the possible use of the obtained colloids, which consisted of GNPs and capping biomaterial, in therapeutic applications. Moreover, the synthesized GNPs showed good antibacterial activity toward E. coli indicating their potential in biological applications.

Abstract: We present fabrication of silver nanostructures on glass substrates using highly energetic and high fluence material ions generated by one shot of hot, dense and extremely non-equilibrium plasma such as found in modified dense plasma focus (DPF) device. The substrates were first placed at 4.0 cm and 6.0 cm from the top of anode. Nanodots and nanocapsules are observed in the scanning electron microscopy (SEM) images of silver ions deposited with DPF shot on glass. The interparticle distance is found to decrease whereas mean size of nanodots is found to increase slightly when the distance of glass substrate is increased from 4.0 cm to 6.0 cm. The X-ray diffraction (XRD) pattern of the fabricated nanostructures has peaks at 2θ equals 37.90o, 44.24o and 64.20o which correspond to (111), (200) and (220) planes of silver having face-centered cubic structure. The nanostructures obtained on glass placed at 4.0 cm show surface plasmon resonance (SPR) peak at 420 nm whereas nanostructures obtained on glass placed at 6.0 cm has a SPR peak at 428 nm. Redshift of the SPR peak is attributed to increased interaction as a result of decrease in interparticle distance of the nanostructures as well as increase in mean size of nanodots.

Abstract: Sb-doped ZnO nanostructures have been deposited on to glass substrates via microwave-assisted process form Zn-Sb with different 1, 2 and 3 % by atomic weight. As the Sb/Zn mole ratio of the microwave oven materials increases, the Sb content doped in to the ZnO increases size, and the shape of the ZnO nanomaterials could be controlled via doping Sb. The structural and properties of undoped and doped ZnO were characterized by various techniques including by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopy. Finally, the controlled growth mechanism of ZnO nanomaterials was discussed in detail.

Abstract: This paper is focused on the study of the effects of the injection strategy and fuel blends on spray combustion and soot formation in compression ignition engines. UV-visible natural emission spectroscopy was applied in the combustion chamber of a single cylinder high swirl compression ignition engine equipped with a common rail multi-jet injection system. The engine was fuelled with low-sulphur neat diesel and blended with 20 and 40% by volume of n-butanol. For all the fuels, the evolution of radical species, such like OH and soot was followed during the spray combustion processes examining different pilot-main dwell timings. Optical data were correlated to engine parameters and exhaust emissions.

Abstract: Silver Nanoparticles (Ag-NPs) have been known to have inhibitory and bactericidal effects. Resistance to antimicrobial agents by pathogenic bacteria has emerged in recent years and is a major health problem. The ability of some microorganisms such as bacteria and fungi to control the synthesis of metallic Nanoparticles should be employed in the search for new materials. The present work is the study of biosynthesis of silver Nanoparticles synthesized from different Penicillium spp. The Penicillium species were identified by employing microscopic methods and laboratory manuals. The Nanoparticles synthesis was done by extracellular and intracellular methods. The silver Nanoparticles formed were characterized by Uv-vis spectrophotometer followed by TEM analysis. The maximum absorbance 410nm confirmed the formation of silver Nanoparticles and TEM revealed the particle size in the range of 30-40nm, which after confirmation was checked for its antibacterial activity against selected microbial pathogens like Bacillus cereus, Proteus vulgaris, Staphylococcus aureus and Staphylococcus epidermidis. The Nanoparticles synthesized by Penicillium species showed a well anti microbial activity that was further compared with different antibiotics to check the Nanoparticles activity which can be substituted in place of high dose antibiotics.

Abstract: The proposed study was to synthesize silver nanoparticles by using filamentous fungus Penicillium fellutanum. From the ancient period, silver has been used against microorganisms due to its own antibacterial properties. The fungal culture of Penicillium fellutanum was isolated from the soil samples of Sathyabama University, Chennai, Tamil Nadu, India. The fungal isolates were inoculated in culture medium and incubated at room temperature for three days and the culture filtrate was separated and divided into two parts. One part of the culture filtrate was mixed with equal volume of 1mM silver nitrate [AgNO_3,(1 mM)] and agitated at room temperature in dark condition. And the second half was kept as such. In the other hand only 1mM silver nitrate was added into the equal volume of Milli Q water and one half was plain Milli Q water. All the four samples were tested against pathogens like Bacillus cereus, E. coli, Proteus vulgaris, Staphylococcus aureus, Staphylococcus epidermidis and the results were compared. Proteus vulgaris showed the highest zone where E coli showed the least zone of inhibition, in the culture filtrate added with silver nitrate. The cell filtrate on treatment with silver nitrate and prior incubation were observed for change in color and characterized by UV-Vis spectrophotometer which detected AgNPs in the solution. The maximum absorbance 410nm confirmed the formation of silver nanoparticles. Size and morphology of silver nanoparticle were investigated using Atomic Force microscopy (AFM). The silver Nanoparticles after confirmation were checked for its antibacterial activity against selected pathogenic bacteria. The biologically synthesized Nanoparticles from Penicillium fellutanum showed the good inhibitory effect against the selected pathogens, which would be the novel remedy substituent in the place of high dose antibiotics.

Abstract: MFe₂O₄ (Where M = Cu²⁺, Co²⁺ and Ni²⁺) has been synthesized using a citrate sol-gel self-ignition process in order to investigate their catalytic performance for reduction of p-nitrophenol. The ignited precursors were annealed at 400, 600, 800 and 1000 ^°C for 2 hrs. to obtain nanoferrite particles. The prepared samples were characterized using various instrumental techniques like FT-IR, XRD, and UV-VIS. X-ray analysis confirms the formation of single phase. Powder X-Ray diffraction patterns showed the formation of body centered tetragonal structure for CuFe₂O₄ and cubic structure for CoFe₂O₄ and NiFe₂O₄. It was observed that as the annealing temperature increases from 400 to 1000 ^°C, the XRD peaks grow sharper attributing to an increase in particle size with increasing temperature; which is consistent with TEM. Transmission Electron micrographs analysis revealed an enhancement in grain size with the annealing temperature. The disappearance of yellow colour indicated the conversion of p-nitrophenol to p-aminophenol and the occurrence of colour disappearance has been observed in one minute using CuFe₂O₄ (8mol %). This suggested the efficiency of CuFe₂O₄ in catalyzing p-nitrophenol reduction. FT-IR and UV-Visible spectroscopy has been used to confirm this reduction process. FT-IR spectra showed N-H stretching vibrations at ~3365 cm^-1 and 3350 cm^-1 attributing to the formation of primary amine using CuFe₂O₄ for catalyzing reduction of p-nitrophenol. The disappearance of the absorption band at 400 nm in the UV-Visible spectrum also confirms the conversion of p-nitrophenol to p-aminophenol.