Continuous Fixed-Bed Column Studies of Textile Effluent Treatment using Multi-Walled Carbon Nanotubes Originated from Rosmarinus officinalis Oil

A continuous adsorption study in a fixed-bed column was carried out using Multi-walled Carbon Nanotubes derived from Rosmarinus officinalis oil as an adsorbent for removing the textile dye Acid blue 40 from an aqueous solution. The adsorbent, MWNTs were prepared from Rosmarinus officinalis oil as a precursor to Fe/Mo catalyst supported on silica at 650 ºC under N2 atmosphere by spray pyrolysis process characterized by scanning electron microscopy, Transmission Electron microscopy, and Raman spectroscopy. The effects of adsorbent bed height (2–6 cm), initial ion concentration (20– 60 mg/L), and flow rate (10–30 mL/min) on the column performance were analyzed. The breakthrough curve was analyzed using the mathematical models of Thomas, Yoon-Nelson, and bed depth service time. The Thomas model at different conditions defined the behaviors of the breakthrough curves. The bed depth service time model showed good agreement with the experimental data. The high values of correlation coefficients (R2 0.9875) obtained indicate the validity of the bed depth service time model for the present column system.

Carbon-Based Materials from Borassus flabellifer and their Applications

Plant-based carbon materials are a high-demand source nowadays, as they are low-cost, eco-friendly, easily available, and sustainable. Borassus flabellifer (Palmyra palm) is a gift of nature that gives numerous benefits, as all parts of the tree can be used for multiple purposes. Palmyraculture is the practice of cultivating Palmyra palms and utilizing them to live a self-reliant life in working towards sustainable development. Due to the advancement of technology, Borassus flabellifer is used to synthesize carbon materials, including hard carbon, carbon nanodots, charcoal, and activated carbon. These carbon materials can be used in electrochemistry as anode materials, biosensing, bioimaging, catalysts, and water purification. This review mainly focuses on the carbon materials derived from the Borassus flabellifer, their applications in various fields, and further aspects that have to be considered.

Synthesis and Characterization of Ag-Decorated TiO2 Nanoparticles for Photocatalytic Application

TiO2 nanoparticles (TiO2) and Ag-doped TiO2 nanocomposites (Ag-TiO2) were synthesized by the Sol-Gel process using titanium tetra isopropoxide as TiO2 and AgNO3 as Ag precursors, respectively. The synthesized nanocomposites were characterized by XRD, SEM, TEM, FT-IR, and UV­-Visible analysis. The XRD results show that Ag doping increases the grain size from 22 nm to 36 nm. From the UV-Visible spectra, the redshift in absorbance was observed, which indicates the increase in grain size and it reduces the bandgap. The TEM analysis shows that all the particles are exhibited in the nanometer range. The synthesized nanoparticles show good photocatalytic activity, and they decompose the methyl orange dye within 5 hours.

Characterization Studies of a GC based SAW Sensor System for Potential Detection and Identification of Toxic Environmental Gases/Vapors

The characterization of a custom-designed GC-based SAW e-Nose sensor system is presented here to study the sensing ability of the sensor system to detect and identify low medium and high toxic vapors. A semi-automated multi-vapor generator generates vapors of chemical compounds that are then exposed to the sensing system to examine its performance under various concentrations. Time-domain verses frequency response of GC-SAW Sensor is noted for repeated cycles against different chemical compounds like xylene, 1,2 dibromoethane, dimethyl sulfate, triethyl phosphate, nitrobenzene, phosphorous trichloride being tested. The generated data is examined using a principle component analysis (PCA) technique to detect a unique response for an individual chemical compound. Experimental results are reported.

Synthesis and Characterisation of Pure Zirconium Oxide (ZrO2) Nanoparticle by Conventional Precipitation Method

In this paper, the synthesis of Zirconium oxide (ZrO2) nanoparticles was carried out by the Conventional precipitation method. Ultraviolet, visible spectroscopy (UV-Vis), and dynamic light scattering analysis (DLS) were performed to find the particles' bandgap and size. Fourier transform infrared spectroscopy (FT-IR) observed the characteristic bands of Zirconium oxide nanoparticles. Dynamic light scattering analysis showed that the size of the particle was found to be 119 nm.

Nd-Doped Barium Cerate Nano-Sized Catalyst Converts CH4 into CO2 at Lower Temperature Compared to Noble Metal-Based Pd/Al2O3 Catalyst

The present paper describes the synthesis and first application of Nd-doped BaCeO3 nanoparticles as catalyst for the catalytic oxidation of methane (CH4) into CO2. Nd-doped barium cerate BaCeO3 nanoparticles, with the formula BaNdxCe(1-x)O3, have been prepared using a simple sol gel method starting from acetate precursors. The as-prepared nanoparticles have been fully characterized by XRD, TEM, HRTEM and specific surface area measurement. Results confirmed the formation of highly crystallized nano-sized particles with small crystallite size. In-situ FTIR spectroscopy was used to study the catalytic conversion of methane (CH4) into CO2 in the presence of the as-prepared Nd-doped BaCeO3 nanocatalyst. The catalytic properties of such nanocatalysts have been discussed and correlated to Nd-doping rate, crystallite diameter, and specific surface area of the materials. Excellent catalytic properties have been obtained with BaNd0.05Ce0.95O3, such as, superior conversion efficiency, longer catalysis lifetime and lower activation temperature compared to un-doped BaCeO3 catalyst. Interestingly, it was found that BaNd0.05Ce0.95O3 nanocatalyst successfully converts the totality of CH4 present in a mixture of CH4-Air into CO2 at much lower temperature compared to the conventional Pd/Al2O3 catalyst.

Synthesis of Environment Friendly Manganese Doped Metal Oxide Nanoparticles for the Bio sensor Applications

The present work focuses the synthesis of Manganese(Mn) doped Fe2O3 nanoparticles via an environmental friendly method which find their suitability for biosensors applications using the extraction of Nyctanthes arbor tristis seed for the first time. The synthesized Mn (~2, 3 & 5 wt. %) doped Fe2O3 were characterized by Powder X-ray diffraction (XRD), Field emission Scanning electron microscopy (FE-SEM), Cyclic voltammeter, Infrared and UV visible spectroscopic studies. The powder X-ray diffraction analysis exposed the phase formation and α - Fe2O3 nanoparticles in the case of annealed sample. Also, interesting secondary phase formation observed in the case of Mn 5wt. % doped samples. The optical properties of Mn (~2, 3 & 5 wt. %) doped Fe2O3 samples was determined by utilizing UV – Visible spectroscopic technique and the corresponding band gap energy was found to be 5.83 eV. The chemical bonds as well as functional groups in the compound were confirmed by the analysis of FT-IR spectrum. The morphology of the prepared samples were observed at micro level using FE-SEM analysis.Cyclic voltammeter was used to find the suitability of the prepared samples for proposed bio sensor applications.

Green Synthesis of Silver Nanoparticles using the Leaves Extract of Filicium decipiens and its Anti- Microbial Activity

Silver nanoparticles has been used since ages, even till now it is exploited in almost all areas like medicine, textiles, industries, cosmetics, purification, dying and many more. There are many approaches which are used to synthesize silver nanoparticles. However, these approaches are either harmful to the environment or very costly. Therefore, green synthesis of silver nanoparticles (AgNPs) using leaves of Filicium decipiens eco-friendly and a very reliable method to procure AgNPs. Characterization of synthesized AgNPs were then done using UV-Vis spectroscopy and fluorescence which confirmed the formation of AgNPs, scanning electron microscope (SEM)confirmed its shape to be round and X-ray diffraction (XRD) determined its crystalline nature as face centered cubic structure. Furthermore, Dynamic Light Scattering (DLS) was also done in order to know the average diameter and zeta potential of AgNPs. However, it did not show potential results due to the aggregates formed during the green synthesis of AgNPs. In addition to this, anti-microbial test against bacteria such as gram negative (Escherichia. Coli) and gram positive (Bacillus.spc) were done using well-diffusion method and also its application of antimicrobial activity was tested over fabric to understand its application in textile industries. In both the cases, AgNPs showed more efficiency in gram negative bacteria than gram- positive.

Synthesis of Ag Decorated TiO2 Nanoparticles for Ammonia Gas Sensor Application

In this research, nanometer size clusters of TiO2 have been successfully synthesized through sol-gel method. Further, at different concentration of Ag were further deposited on TiO2. After successful deposition of TiO2: Ag the gas sensing performance of the sample has been studied at different exposure of NH3(ammonia) gas. Analysis has been done via XRD to evaluate the grain sizes of the nanoparticles and calculated 18 nm for TiO2 and 12 nm for 5% Ag doped TiO2. EDS has been conducted, ensured that Ag has been successfully decorated on the superficial of TiO2. The formation of nano size particles has been confirmed by TEM analysis. FTlR analysis confirmed the existence of TiO2 and Ag. The surface state emission of TiO2: Ag nanoparticles can be seen in the PL spectrum at 383 nm, 450 nm, and 465 nm. As the exposure of NH3 gas increases from 50 to 250 ppm, the impedance range displayed a decrease in semicircle radius, which was then marginally increased. The variance in resistance also contributed to the gas sensing properties due to grain boundaries, in accordance to impedance spectroscopy review.