Effect of Fe Doping on Photocatalytic Dye-Degradation and Antibacterial Activity of SnO2 Nanoparticles

A simple hydrothermal method is utilized to synthesize iron-doped tin oxide nanoparticles (Fe-SnO2 NPs) at various doping concentrations. The structural characterization using XRD, Raman, and FTIR measurements confirmed the incorporation of Fe ions into the SnO2 lattice without any deviation in the tetragonal crystal system of SnO2 nanoparticles. SEM and HRTEM images show the spherical-shaped nanoparticles with agglomeration. The values of interplanar spacing ( d -value) calculated from the HRTEM lattice are consistent with the XRD results. Further, optical analysis revealed a red shift in the optical absorption band and a decrease in the band gap energy with an increase in Fe-dopant concentration. The decrease of PL emission peak intensity with Fe doping revealed the generation of singly charged oxygen vacancies. The H2O2-assisted photocatalytic degradation efficiency of Fe-SnO2 NPs investigated against crystal violet dye indicated an efficiency of 98% for 0.05 M Fe-SnO2 NPs within 30 minutes under visible light illumination. In addition, the effects of pH, scavengers, and reusability of the catalyst are tested. The antibacterial behavior of Fe-SnO2 NPs against Escherichia coli is examined by using the colony count method, and the inhibition rate was found to be 49, 65, 70, and 78% for pure, 0.01, 0.03, and 0.05 M Fe-SnO2 NPs, respectively

Studies on lipase enzyme production by indigenously isolated Bacillus Cereus (BAIT GCT 127002 ) and Bacillus Cereus (BAIT GCT 127001)

Microbial lipases holds a prominent place among biocatalysts that act on carboxylic ester bonds.  This present study involves about eight strains isolated form slaughter house waste water,Coimbatore producing lipase.Among those strains , two bacterial strains exhibiting high lipase production  were identified as  Bacillus Cereus (BAIT GCT 127002 ) and Bacillus Cereus (BAIT GCT 127001 ) by both biochemical analysis and 16S rRNA sequencing.  Initial studies were done for optimizing lipase production using many components such as time course,Carbon sources ,pH and innoculum volume which  revealed maximum lipase acitivity (43.37 U/ml) at 24 hours, using  palm oil , at pH 8 and innoculum volume of 1 ml by Bacillus Cereus (BAIT GCT 127002 ).Further the percentage  removal of oil from oil stained fabric was determined using partially purified lipase with or without detergents and the results indicated 20% ,30% removal with use of  crude lipase and commercial detergent respectively.Hence, lipase from Bacillus Cereus(BAIT GCT 127002 )   can be regarded as an ideal ingredient that can be used in the laundry detergents.Â&nbsp

Підвищена чутливість до вологості гідротермально синтезованих наночастинок оксиду олова

Метал-оксидні напівпровідникові наноматеріали широко використовуються для застосування в сонячних елементах, акумуляторах, газових датчиках, оптоелектроніці, фотокаталізі та генерації водню. Датчики вологості на основі метал-оксидних напівпровідників показали значний внесок у галузі моніторингу навколишнього середовища, харчових технологій та біотехнологій. Серед різноманітних метал-оксидних напівпровідників наночастинки оксиду олова (SnO2) викликають більший інтерес завдяки їх високій хімічній стабільності, високій прозорості та низькому електричному поверхневому опору. У роботі наночастинки SnO2 були синтезовані за допомогою простого гідротермального процесу без використання будь-яких поверхнево-активних речовин. Синтезовані наночастинки досліджували за допомогою XRD, SEM, EDAX, UV-visible та вимірювань вологості. Дослідження структурних властивостей зразків з використанням аналізу XRD свідчать про те, що синтезовані наночастинки SnO2 мають чисту кристалічну фазу з тетрагональною кристалічною структурою просторової групи P42/mnm. Морфологія поверхні, проаналізована за допомогою мікрофотографії SEM, показала агломеровані наночастинки без будь-якої конкретної структури. Оптична характеризація за допомогою UV-visible спектроскопії виявила, що синтезовані наночастинки мають сильне поглинання в UV області. Чутливість до вологості, проаналізована на основі зміни питомого електричного опору з відносною вологістю (% RH), показала гарну гістерезисну поведінку, а спостережувані зміни електричної провідності пояснюються на основі механізму протонної провідності на поверхні.Metal oxide semiconductor nanomaterials have been widely used for applications in solar cells, batteries, gas sensors, optoelectronics, photocatalysis and hydrogen generation. Humidity sensors based on metal oxide semiconductors have shown significant contribution in the field of environmental monitoring, food technology and biotechnology. Among the various metal oxide semiconductors, tin oxide (SnO2) nanoparticles have generated more interest due to their excellent chemical stability, high transparency and low electrical sheet resistance. In the present work, SnO2 nanoparticles were synthesized by employing a simple hydrothermal process without using any surfactant. The synthesized nanoparticles were investigated using XRD, SEM, EDAX, UV-visible and humidity sensing measurements. The structural property of the sample investigated using XRD analysis indicated that the synthesized SnO2 nanoparticles have pure crystalline phase with a tetragonal crystal structure of the P42/mnm space group. The surface morphology analyzed using SEM micrograph showed agglomerated nanoparticles without any specific structure. Optical characterization using UV-visible spectroscopy indicated that the synthesized nanoparticles have strong absorption in the UV region. The humidity sensing property analyzed from the variation of electrical resistivity with relative humidity (% RH) showed good hysteresis behavior and the observed variation in electrical conduction is explained based on protonic conduction mechanism on the surface

Stability and rheological study on carbon-based nanofluids

In this study, an organic derived nanofluid has been developed from bio-origin resources. Carbon nanopowder (CNP) is obtained from derived rice husk and was prepared via a simple two-steps thermal process with minimum energy (low temperature and reaction time) using solar assisted plasma furnace. Nanofluids comprised of CNP and EG/water binary mixture has been prepared at various concentration such as 0.02 – 0.10 vol% of CNP. Flow curve of nanofluids showed that at minimum inclusion of CNP improved the stress of the fluid significantly. More to the addition, dynamic viscosity measure possesses that addition of CNP stabilized the properties of the fluid compared to virgin base fluid. Moreover, the stability results showed that the nanofluids stabilized starting from 1 week onwards as evidenced by UV-Visible spectrophotometer analysis. Furthermore, little to no precipitate noticed even after 8 weeks. This work offers greener approach for nanofluids which organic derived and environmentally friendly (very low percentage of nanoparticle, 0.02 vol%