Ethanol steam reforming study over ZSM-5 supported cobalt versus nickel catalyst for renewable hydrogen generation

The renewable hydrogen generation through ethanol steam reforming is one of the anticipated areas for sustainable hydrogen generation. To elucidate the role of Ni and Co with ZSM-5 support, catalysts were prepared by wet impregnation method and ethanol steam reforming(ESR) was performed. The catalysts were characterized by HR-XRD, ATR–FTIR, HR-SEM, TEM with SAED, EDAX, surface area analyzer and TPR. It had shown complete ethanol conversion at 773 K, but the selectivity in hydrogen generation was found higher for 10% Ni/ZSM-5 catalyst as compared to 10% Co/ZSM-5. The 10% Ni/ZSM-5 catalyst has about 72% hydrogen selectivity at temperature 873 K. It indicates that Ni is a more sustainable catalyst as compared to Co with ZSM-5 support for ESR. The C_2H_4 was found major undesirable products up to 823 K temperature. Nevertheless, the 10% Ni/ZSM-5 catalyst had shown its stability for high temperature(873 K) ESR performance.     

CFD analysis of performance improvement of the Savonius water turbine by using an impinging jet duct design

The majority of research on water turbines focuses on design improvement of large-scale hydrokinetic turbines for power generation, which may have delayed the utilization of kinetic energy contained in rivers and canals. The aim of this paper is to improve the efficiency of a two bladed Savonius type cross-flow hydrokinetic turbine, which can be used as an energy converter to harness free-stream kinetic energy of water. An impinging jet duct design is presented for improving performance of the Savonius turbine in wind application as seen from literature. The performance of the modified turbine is evaluated using CFD software Fluent, and is compared with that of a simple two bladed Savonius water turbine and some of the prominent literature designs of the Savonius turbine. It is shown that the present design exhibits improved performance compared to the selected designs of the Savonius turbine.Further an insight of the improved performance of the modified turbine is also obtained from flow physics study.     

Latest developments on application of heterogenous basic catalysts for an efficient and eco friendly synthesis of biodiesel: A review

Heterogeneous catalysts are now being tried extensively for biodiesel synthesis. These catalysts are poised to play an important role and are perspective catalysts in future for biodiesel production at industrial level. The review deals with a comprehensive list of these heterogeneous catalysts which has been reported recently. The mechanisms of these catalysts in the transesterification reaction have been discussed. The conditions for the reaction and optimized parameters along with preparation of the catalyst, and their leaching aspects are discussed. The heterogeneous basic catalyst discussed in the review includes oxides of magnesium and calcium; hydrotalcite/layered double hydroxide; alumina; and zeolites. Yield and conversion of biodiesel obtained from the triglycerides with various heterogeneous catalysts have been studied.     

Hen Egg White Lysozyme Catalyzed Efficient Synthesis of 3-Indolyl-3-hydroxy Oxindole in Aqueous Ethanol

A green synthesis of 3-indolyl-3-hydroxy oxindoles was reported using hen egg white lysozyme (HEWL) in an aqueous ethanol. The HEWL promotes this reaction efficiently from various isatins and indoles under mild reaction conditions with yields up to 98% bearing good adaptability to varied substrates in the reaction. This conversion has provided a new strategy to synthesize 3-indolyl-3-hydroxy oxindole derivatives employing biocatalytic promiscuity of less explored lysozyme. Based on the experimental studies, the plausible reaction mechanism is proposed.

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Synthesis of economically viable biodiesel from waste frying oils (WFO)

In present communication, waste frying oil (WFO) has been used as a feedstock for biodiesel synthesis. WFO, procured from a local Indian restaurant possessed an acid value of 0.84 mg KOH/g, which is low enough for single step transesterification reaction. Biodiesel (fatty acid methyl esters) was washed after transesterification reaction and the yield got lowered substantially (from 96% to 86.36%) after water washing owing to loss of esters. 30:100 vol% (methanol to oil), 0.6 wt% NaOCH₃, 60°C temperature and 600 rpm agitation in 1 h reaction time was found to be optimum for transesterification reaction. ¹H NMR spectrum showed a high conversion (95.19%) of fatty acids in WFO to biodiesel in 2 h reaction time. Almost complete conversion (99.68%) was attained in 2 h reaction time. © 2011 Canadian Society for Chemical Engineering     

Effect of midblock on the morphology and properties of blends of ABA triblock copolymers of PDLA-mid-block-PDLA with PLLA

A method to overcome the brittleness of poly (l-lactic acid) (PLLA) by kinetically trapping a continuous low T_g amorphous phase is presented. This morphology is accomplished by exploiting the significant difference in the crystallization temperatures of PLLA vs its stereocomplex with the poly (d-lactic acid) (PDLA) isomer. In our studies, the D isomer is the end block of a triblock copolymer with a configuration of the form PDLAn–Soft Blockm–PDLAn. As demonstrated in this study, when blended with PLLA, the obtained morphology, and improvement in the sample toughness and flexibility, strongly depend on the miscibility of the midblock in the triblock copolymer with the matrix PLLA. The difference in the chemical nature of the midblock clearly affected the stereocomplex crystallization between the PDLA end blocks, the PLLA matrix polymer, and the morphology formed. It is found that the miscible midblock gives rise to a soft continuous amorphous phase while in the case of an immiscible midblock, a glassy phase separated amorphous phase is formed. Dramatically different physical properties can be obtained for various PLLA/triblock copolymer blends giving access to tough, yet flexible, semicrystalline PLLA blends.     

Synthesis and Characterization of Porogen Based Porous Low-k Thin Films

The present work is focused towards the lowering of the k value of deposited SiO₂ thin films by varying solvent concentration i.e. ethanol in the range 4-10 ml. Porous low-k thin films were synthesized by using the sol-gel spinon technique. A non-ionic surfactant polysorbate 80 (Tween 80) was used as a porogen to generate the porosity in the film matrix. The lower values of refractive index and film density were measured to be 1.19 and 0.94 gm/cm³ respectively for 10 ml solvent concentration. Further, the lowest k value of 2.2 and highest porosity percentage of 58.5 % were obtained for the same film due to the dilution of coating solution at higher solvent concentration. The water contact angle of the film was observed to be increased to 106.3° which indicates the transformation of the deposited film surface from hydrophilic to hydrophobic. The change in chemical structure as an effect of solvent concentration is studied by using FTIR. From FTIR spectra the disappearance of Si-OH groups at higher solvent concentration reveals the increase in condensation rate. Overall in this study, the result shows the significant change in structural, chemical and optical properties of the deposited films at 10 ml solvent concentration. Such deposited porous thin films with lower k value and enhanced hydrophobicity can be used as an interlayer dielectric (ILD) for back end of line (BEOL) in CMOS technology.     

Biodegradation Behavior of DOC Isolated Mixed Proteins-Based Plastic Sheets

The biodegradability of plastic sheets made of mixed proteins was investigated. Soybean, castor and rapeseed DOC (Deoiled Cake) isolated proteins-based plastic sheets were subjected to microbial degradation using Pseudomonas aeruginosa. Results from the microbial degradation showed that plastic sheets prepared from mixture of soybean, castor and rapeseed proteins could support the growth of P. aeruginosa. Biodegradable plastic sheet with composition (80:10:10 and 60% PEG₄₀₀) degraded much faster than the other four biodegradable plastics sheets under the conditions examined, suggesting that the biodegradability of protein films is associated with the film composition and the extent of covalent cross-linking.     

Transport of cobalt(II) through a hollow fiber supported liquid membrane containing di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the carrier

This work presents experimental, modeling and simulation studies for Co²⁺ ion extraction using hollow fiber supported liquid membrane (HFSLM) operated in a recycling mode. Extractant di-(2-ethylhexyl) phosphoric acid (D2EHPA) diluted with kerosene has been used as the membrane phase. The Co²⁺ ion concentration in the aqueous feed phase was varied in the range of 1–3 mM. Also, D2EHPA concentration was varied in the range of 10–30% (v/v). A mass transfer model has been developed considering the complexation and de-complexation reactions to be fast and at equilibrium. Equations for extractant mass balance and counter-ion (H⁺) transport have also been incorporated in the model. Extraction equilibrium constant (K_ex) for cobalt–D2EHPA system has been estimated from equilibration experiments and found to be 3.48 × 10⁻⁶. It was observed that the model results are in good agreement with the experimental data when diffusivity of metal-complex (D_m) through the membrane phase is 1.5 × 10⁻¹⁰ m²/s. Feed phase pH and strip phase acidity had negligible effect on the extraction profiles of Co²⁺ ions. An increase in D2EHPA concentration increased extraction rates of Co²⁺ ions. The membrane phase diffusion step was found to be the controlling resistance to mass transfer.