Oxidation of polycyclic aromatic hydrocarbons with hydrogen peroxide catalyzed by Iron(III)porphyrins

A variety of iron-metallated functional porphyrins have been synthesized and their catalytic activity to oxidize polycyclic aromatic hydrocarbons, (PAHs) using hydrogen peroxide as oxidant was investigated. It was found that iron-metallated porphyrins bearing strong electronegative groups at β-pyrrolic positions show an exceptionally high catalytic efficiency.     

A structural study on MFCl (M=Ca, Sr, Ba) and BaFX (X=Br, I)

Here we present the electronic band structure calculations of CaFCl, SrFCl, BaFCl, BaFBr and BaFI performed using tight binding linear muffin-tin orbital method. The calculated ground state properties namely the lattice parameters, bulk moduli and the pressure-volume relations were found to be in good agreement with the experimental values. The electronic band structure of these compounds were calculated at ambient as well as in the high pressure region. The band gap values of these insulating systems were calculated and compared with available experimental values. At high pressure these compounds exhibit the interesting phenomenon of band overlap metallization.     

Biogenic synthesis and thermo‐magnetic study of highly porous carbon nanotubes

Nanomaterials synthesis using natural sources is the technology to up come with advanced materials through extracts of plant, microorganisms, poultry waste etc. In this study, the authors report the synthesis of porous carbon nanotubes using high‐temperature decomposition technique facilitated by cobalt salt using chicken fats, a poultry waste as a precursor. Since chicken fats contain fatty acids which can decompose into short hydrocarbon chains and cobalt can act as the catalyst. The formation of carbon nanotubes was confirmed by Raman spectra, peaks at 1580 and 1350.46 cm⁻¹ confirmed the graphite mode G‐band and structural imperfections defect mode D‐band, respectively. Transmission electron microscopy showed the formation of tube‐like structures. Nitrogen adsorption–desorption studies showed the high‐surface area of 418.1 m² g⁻¹ with an estimated pore diameter of 8.1 nm. Thermogravimetry analysis–derivative thermogravimetric analysis–differential thermal analysis showed the instant weight loss at 517°C attributed to the rapid combustion of nanotubes. A vibrating‐sample magnetometer showed the paramagnetic nature of the so‐formed carbon nanotubes formed.Inspec keywords: transmission electron microscopy, infrared spectra, nanomagnetics, pyrolysis, decomposition, adsorption, desorption, carbon nanotubes, differential thermal analysis, thermal analysis, nanofabrication, Raman spectra, X‐ray diffraction, scanning electron microscopy, paramagnetic materialsOther keywords: biogenic synthesis, highly porous carbon nanotubes, microorganisms, high‐temperature decomposition technique, cobalt salt, chicken fats, fatty acids, short hydrocarbon chains, Raman spectra, graphite mode G‐band, structural imperfections defect mode D‐band, transmission electron microscopy, paramagnetic nature, thermo‐magnetic properties, poultry waste, nitrogen adsorption‐desorption studies, thermogravimetry analysis, differential thermal analysis, carbon nanotubes, temperature 517.0 degC, C     

A study on the sorption of NO3− and F− on the carboxymethylated starch‐based hydrogels loaded with Fe2+ ions

Using the principle of geochemistry of fluoride, green and cost effective anion adsorbents were developed for the removal of F^? from water systems. The scheme was further applied for the removal of NO₃^? also. Carboxymethylated starch functionalized through network formation with acrylamide was used as adsorbent, and the resultant hydrogels were loaded with Fe²⁺ ions to generate anchorage for the anions. Sorption of Fe²⁺ was studied as a function of different factors such as time, temperature, pH, and ion strength. The network having the highest Fe²⁺ uptake was loaded with the Fe²⁺ ions under optimum conditions and used for the sorption of F^? and NO₃^?. High efficiency has been observed for F^?, as even up to 100% uptake has been observed within just 10 minutes. The support shows high selectivity for NO₃^?, which was used as anion reference. Thermodynamics of sorption confirms low order and low energy processes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Nanoparticle‐loaded UV‐blocking contact lenses

We have developed a novel approach of incorporating UV‐blocking features into contact lenses by dispersing nanoparticles into the lenses. The nanoparticles are prepared by controlling polymerization dynamics using chain terminating and chain transfer agents. A theoretical model is developed to predict the effect of various formulation parameters on the particle size. This approach can produce UV‐blocking nanoparticles of controlled size below 10 nm in diameter with close to 10% conversion. The model predictions for the mean size are in reasonable agreement with the experimental data. The nanoparticles are cleaned and loaded in silicone hydrogel contact lenses by soaking the lenses in a solution of particles in ethanol and acetone. Lenses loaded with about 6% particles w/w in the hydrated lens block sufficient UV light to be classified as Class 1 blockers. The nanoparticles are retained in the lens during soaking in phosphate buffered saline (PBS) and are stable to sterilization by autoclaving. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42495.     

Uranyl ions uptake on poly(AAc/AAm)-cl-N,N-MBAAm hydrogel

In the present article, we report two well-characterized hydrogels for the adsorption of uranyl ions from 5% NaCl solution. The hydrogel was synthesized by free radical initiation from acrylamide and acrylic acid using N,N-methylenebisacrylamide as crosslinker. In order to improve ion uptake performance, the hydrogel was hydrolyzed to partially convert some of the amide groups into carboxylate groups. The uranyl ion adsorption was studied as a function of hydrogel structure, uranyl ions concentration, pH, temperature, and mass of hydrogel. The partially hydrolyzed hydrogel exhibited the maximum uranyl ion uptake of 236.6 mgg⁻¹ in 480 min at 45 °C and at pH 13. Good reproducibility of results was observed and the evidence of sorption at the optimum pH and ion concentration was obtained by comparison of FTIR spectra of the precursor and uranyl ions loaded hydrogels. The performance of both the hydrogels was found to be higher than that of a commercial resin, Amberlite IRC-718. The experimental data shows good match with Langmuir and Freundlich isotherms and pseudo-first order kinetics.     

Studies on corrosion control of naphtha fractions in overhead condensing system using laboratory distillation device

Corrosion in the overhead condensing system of atmospheric distillation units is a common occurrence in petroleum refineries worldwide. These corrosion problems are influenced by the presence of three phases: vapours, liquid hydrocarbons and aqueous phase containing hydrochloric acid formed during distillation by decomposition of chloride salts of calcium and magnesium.Present studies highlight the corrosion control of naphtha fractions of Bombay High and Dubai crude oils in laboratory distillation device by chemical treatment using various corrosion inhibitors having different functional groups. These studies were carried out using two phase systems (aqueous-hydrocarbon) in the distillation device having facilities for monitoring the corrosion and temperatures in vapour condensing region and liquid condensate. Corrosion monitoring was carried out by potentiodynamic polarization technique and dissolved iron analysis using inductively coupled plasma atomic emission spectroscopy (ICPAES). Experimental findings indicate that Dubai naphtha fraction is more corrosive in nature when compared to Bombay High naphtha. This observation can also be explained on the basis of characterization of both crude oils and their naphtha fractions. At normally recommended dosage level as in refinery overhead systems, water soluble corrosion inhibitors are more effective than hydrocarbon soluble ones in the vapour condensing region as well as in the liquid condensate of both naphtha fractions.     

On the solution and applicability of bivariate population balance equations for mixing in particle phase

New benchmarks are used to test two classes of discretization methods available in the literature to solve bivariate population balance equations (2-d PBEs), and the applicability of these mean-field equations to finite size systems. The new benchmarks, different from the extensions of their 1-d counterparts, relate to prediction of kinetics of mixing in particle phase under: (i) pure aggregation of particles, called aggregative mixing, and (ii) simultaneous breakup and coalescence of drops. The discretization methods for 2-d PBEs, derived from the widely used 1-d solution methods, are first classified into two classes. We choose one representative method from each class. The results show that the extensions based on minimum consistency of discretization perform quite well with respect to both the new and the old benchmarks, in comparison with the geometrical extensions of 1-d methods. We next revisit aggregative mixing using Monte-Carlo simulations. The simulations show that (i) the time variation of the extent of mixing in finite size systems has power law scaling with the system size, and (ii) the mean-field PBEs fail to capture the evolution of mixing for reduced population of particles at long times. The sum kernel limits the applicability of PBEs to substantially larger particle populations than that seen for the constant kernel. Interestingly, these populations are orders of magnitude larger than those at which the PBEs fail to capture the evolution of total particle population correctly.     

Phytic acid and extractable phosphorus of pearl millet flour as affected by natural lactic acid fermentation

Lactic acid fermentation of pearl millet flour decreased its phytic acid content and increased extractable phosphorus. Fermentation at 40 and 50°C for 72 h or longer eliminated phytic acid almost completely; extractable phosphorus was more than doubled. Lower temperatures (20 and 30°C) were less effective. The changes in concentration of phytic acid and extractable phosphorus may be attributed partly to phytase activity inherent in pearl millet flour.     

Taguchi method to optimize the micron and submicron size cenosphere particulates filled E‐glass fiber‐reinforced vinylester composites

In this work, the mechanical and tribological characteristics of E‐glass fiber‐reinforced vinylester composites have been investigated experimentally under dry sliding conditions. The E‐glass fiber‐reinforced vinylester composites with uniform micron and submicron size cenosphere particulates of three different sizes (2 µm, 900 nm, and 400 nm) had been prepared in the laboratory. In this work the effect of parameters such as applied normal load, particulate size, sliding speed, sliding distance and roughness on friction and wear behavior have been carried. A plan of experiments, based on the Taguchi design, was performed to acquire data in a controlled way. An orthogonal array L₂₇ (3¹³) and Analysis of variance (ANOVA) have been applied to investigate the influence of process parameters on the coefficient of friction (COF) and sliding wear behavior of these composites. It was found that the submicron size particulates 400 nm as filler contributed significantly to improve the mechanical properties and wear resistance of the composites. The experimental results indicate that the specific wear rate is greatly influenced by applied normal load and particle size. ANOVA results showed that the applied normal load significantly influence the specific wear rate of cenosphere filled glass fiber‐reinforced vinylester composites. Regression analysis is carried to check the suitability of the prediction equation and modeling of the wear parameters and the typical R² values for COF and specific wear rate are 86.7 and 94.3%, respectively. The scanning electron microscopy are used clarify the experimental in the frictional and wear testing. POLYM. COMPOS., 35:775–787, 2014. © 2013 Society of Plastics Engineers