PHOTOCATALYTIC DEGRADATION OF PHARMACEUTICAL DRUG ZIDOVUDINE BY UNDOPED AND 5 % BARIUM DOPED ZINC OXIDE NANOPARTICLES DURING WATER TREATMENT: SYNTHESIS AND CHARACTERISATION

Objective: To study the photocatalytic degradation of pharmaceutical drug zidovudine (ZDV) by synthesized undoped zinc oxide nanoparticles (ZONPs) and 5% (mole ratio) barium doped zinc oxide nanoparticles (BZONPs) during water treatment.Methods: Kinetics studies were carried out with the help of UV-Visible Spectrophotometer. High-Resolution Mass Spectrophotometry (HR-MS) was used to identify products. A photo-reactor with mercury lamp was used as an external source of light energy. Optical power meter was used for the measurement of light intensity. The particle size of the synthesized photocatalysts was identified with the help of siemens x-ray diffractometer (XRD). The surface topography of photocatalysts was done by scanning electron microscope (SEM). Transmission electron microscopy (TEM) was used for the studies of particle size and morphology.Results: Five degraded products of ZDV are identified by HR-MS. A suitable electron-hole pair mechanism is projected. XRD patterns show that the intensity of peak is slightly stronger in ZONPs. There is an increase in the rate of photocatalytic degradation of ZDV by adding different quantities of photocatalyst from 0.05 g l-1 to 0.1 g l-1. The kinetic data reveals that there is an initial increase in the values of rate constants with the increase in the concentration of ZDV. The kinetic data indicate that the values of rate constants are higher at pH = 9. There is an increase in the rate constant values with an increase in the light intensities of UV lamp.Conclusion: The rates of photocatalytic degradation of ZDV were found to be higher using 5 % (mole ratio) BZONPs as a photocatalyst.Â

Synthesis and Characterization of Fe2O3 Nanoparticles Reinforced to Recycled Industrial Aluminium Scrap & Waste Aluminium Beverage Cans for Preparing Metal Matrix Nanocomposites

Increased material demand in all sectors is primarily due to exponential growth in population to fulfill human needs and comforts. Recycling of collected aluminium beverage cans and Al 6061 alloy scraps from industries ensures energy savings with reduced environmental problems in fabricating composite parts economically. The iron oxide (α-Fe2O3) nanoparticles were prepared by precipitation method using ferric chloride and ammonia as a precursor. The prepared nanoparticles were characterized by using Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR). Stir cast processing route ensures uniform mix of reinforcement nanoparticles in matrix material. The prepared nanocomposites (matrix: Al Scrap (90% Scrap Al 6061 alloy + 10% Waste Al can); reinforcement: 2%, 4% and 6% wt. of Al matrix) were mechanically characterized for hardness and tensile strengths. It was observed that, increased percent of Fe2O3 nanoparticles in the metal matrix nanocomposite (MMCs) resulted in significant increase in hardness and tensile strength values. Fractography analysis examined viz. scanning electron microscope (SEM) revealed a ductile failure for as-cast Al scrap followed by brittle failure in Al MMC's

OFF-AXIS CAVITY ENHANCED ABSORPTION SPECTROMETER BASED ON A MID-INFRARED CONTINUOUS WAVE QUANTUM CASCADE LASER

Author Institution: Department of Chemistry, University of Alberta, Edmonton, AB, T6G; 2G2, CanadaWe present the design and construction of a mid-infrared off-axis cavity enhanced absorption (OA-CEAS) spectrometer equipped with a pulsed slit jet molecular beam expansion. A cw quantum cascade distributed-feedback laser operating at 5.6 \mu$m at the carbonyl stretch frequency was employed. A high finesse optical cavity consisted of a pair of high reflective mirrors with R$>99,9\%$ and separated at a distance of 55 cm was used as a sample cell. A computer program was developed to automate and to synchronize the timing of the cavity enhanced absorption experiments with the pulsed molecular beam. The dominant source of noise in the CEAS experiments arises from incomplete averaging of the cavity mode structures. Several procedures were implemented to minimize the dominant noise due to incomplete averaging of the cavity mode structures: (1) Optimize off-axis alignment to ensure adequate output power and at the same time to excite as many higher order transverse modes as possible, therefore reducing the free spectral range considerably; (2) Modulate the cavity length using a piezoelectric actuator mounted on one of the cavity mirrors; (3) Introduce mechanical perturbation in the optical cavity to randomize the residual mode structures; (4) Optimize laser frequency scan speed to ensure more even intensity distribution of the cavity modes; (5) Apply wavelength modulation to the laser and demodulate the signal with a lock-in amplifier. The CEAS experimental result measured with a static ammonia gas in neon will be presented and compared to that obtained with an astigmatic multi-path cell with 182 passes. The CEAS measurements of jet-cooled infrared spectra of larger organic molecules will also be presented

Nano molar detection of acyclovir, an antiviral drug at nanoclay modified carbon paste electrode

A nano level voltammetric sensing method has been developed for determination of acyclovir (ACV) at nano clay modified carbon paste sensor by employing cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques in pH5.0. The electro-oxidation current of ACV was enhanced two times greater by the modification of the sensor. The modifier nano clay was characterized by utilizing X-ray diffraction (XRD) and scanning electronic microscope (SEM). The influence of parameters like scan rate, pH, accumulation time, amount of the modifier and concentration on the peak current of the drug were studied. The effect of ACV concentration variation was studied using SWV technique and got lowest detection limit compared to the earlier reported techniques. The fabricated sensor was employed for the determination of acyclovir in pharmaceutical and biological samples. Keywords: Antiviral drug, Nano clay particles, Electro-oxidation, Square wave voltammetry, Pharmaceutical analysi

Unusual Anisotropic Effects from 1,3-Dipolar Cycloadducts of 4-Azidomethyl Coumarins

4-Bromomethylcoumarins (1) reacted with sodium azide in aqueous acetone to give 4-azidomethyl-coumarins (2), which underwent 1,3-dipolar cycloaddition with acetylenic dipolarophiles to give triazoles (3). These triazoles (3) have been found to exhibit interesting variations in the chemical shifts of C-3-H and C-4-methylene protons. Protonation studies indicate that the shielding effect of the C-3-H of coumarin is due to pi-electrons of the triazole ring, further supported by diffraction and computational studies

Transformation of linezolid during water treatment with chlorine ─ A kinetic study

38-43The experimental studies on transformation of emerging contaminant linezolid during water chlorination process have been carried out using UV-Visible spectrometer. The pseudo-first order rate constants of linezolid reaction with free available chlorine (FAC) at 5.0 - 8.8 pH have been determined. The second order rate constants are found to decrease with increase in pH (e.g. apparent second rate constant; k”app=2.88 dm3 mol-1s-1 at pH 5.0 and k”app = 0.076 dm3 mol-1 s-1 at pH 8.8 at 298K). Monochlorinated reaction product has been identified by LC/ESI/MS spectra under the experimental conditions. A mechanism involving electrophilic halogenation is proposed based on the kinetic data and LC/ESI/MS spectra. The effect of temperature on the rate of the reaction has been studied at four different temperatures. It is observed that rate constants increase with the increase in temperature and the thermodynamic activation parameters Ea, ΔH#, ΔS# and ΔG# are evaluated for the reaction and discussed. The product of the reaction between linezolid and FAC retains the antibacterial activity. The geometry optimization of the reactants and the products has been done using dispersion corrected density functional (DFT-D) method. All the DFT calculations are accomplished using the TurboMole-5.10 package