Nanomaterials for photo-electrochemical water splitting: a review.

Over the last few decades, the global rise in energy demand has prompted researchers to investigate the energy requirements from alternative green fuels apart from the conventional fossil fuels, due to the surge in CO2 emission levels. In this context, the global demand for hydrogen is anticipated to extend by 4-5% in the next 5 years. Different production technologies like gasification of coal, partial oxidation of hydrocarbons, and reforming of natural gas are used to obtain high yields of hydrogen. In present time, 96% of hydrogen is produced by the conventional methods, and the remaining 4% is produced by the electrolysis of water. Photo-electrochemical (PEC) water splitting is a promising and progressive solar-to-hydrogen pathway with high conversion efficiency at low operating temperatures with substrate electrodes such as fluorine-doped tin oxide (FTO), incorporated with photocatalytic nanomaterials. Several semiconducting nanomaterials such as carbon nanotubes, TiO2, ZnO, graphene, alpha-Fe2O3, WO3, metal nitrides, metal phosphides, cadmium-based quantum dots, and rods have been reported for PEC water splitting. The design of photocatalytic electrodes plays a crucial role for efficient PEC water splitting process. By modifying the composition and morphology of photocatalytic nanomaterials, the overall solar-to-hydrogen (STH) energy conversion efficiency can be improved by optimizing their opto-electronic properties. The present article highlights the recent advancements in cleaner and effective photocatalysts for producing high yields of hydrogen via PEC water splitting.

Silver nanoparticles from Tabernaemontana divaricate leaf extract: mechanism of action and bio-application for photo degradation of 4-aminopyridine.

Silver nanoparticles (Ag NPs) were synthesised by the reduction of Ag+ to Ag0 in the presence of enol form of flavonoids present in plant extract of Tabernaemontana divaricate (T. divaricate). Prepared Ag NPs were characterised using UV-Vis, XRD, HR-TEM with EDX and XPS techniques. XPS spectra exhibited peaks at 366 eV and 373 eV, which specified spin orbits for Ag 3d3/2, and Ag 3d5/2 that confirmed the formation of Ag NPs. Ag NPs were spherical in shape with an average size of 30 nm as revealed by HR-TEM and FE-SEM techniques. EDX studies verified the high purity of Ag NPs with silver 46.96%, carbon 16.35%, oxygen 16.22%, nitrogen 20.25% and sulphur 0.21%. LC-MS analysis of plant extract confirmed the qualitative presence of alkaloids, tannins, flavonoids, phenols, and carbohydrates. Prepared Ag NPs showed good photocatalytic activity towards degradation of 4-Amniopyridine with 61% degradation efficiency at optimum conditions in 2 h of reaction time under visible light. The ten intermediates were found within the mass number of 0-450. Ag NPs synthesised using bio-extract have also shown good inactivation against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria due to the availability of free radicals.

Underutilized finger millet crop for starch extraction, characterization, and utilization in the development of flexible thin film.

Three different varieties of finger millets (VL-315, VL-324, and VL-347) cultivated in Uttrakhand, India, were used to extract high purity starch using the alkali soaking approach and investigated physicochemical and structural properties. VL-315, VL-324, and VL-347, contain 78 ± 0.35%, 79 ± 0.35%, and 87 ± 0.35% starch, respectively, of which 39.03 ± 0.35%, 37.2 ± 0.35%, and 33.5 ± 0.35% are the amylose contents, respectively. Chemical composition analysis exhibited the level of ash and moisture content in the dry basis of 0.0031 ± 0.01% to 0.035 ± 0.05%, and 12.52 ± 0.8% to 12.92 ± 0.2%, respectively. The solubility and swelling range of VL-315 is 1.3-4.3% and 16.54-10.3 (g/g), respectively, which significantly differ from VL-324 and VL-347. XRD analysis revealed that extracted starch showed a typical A-type crystalline network with a crystallinity range of 17.7-19.3%, which remarkably influenced retro gradation tendencies of starch. SEM demonstrated that extracted starch granules are polyhedral shape with a smooth surface. Finger millet starch has enormous potential in the development of starch-based edible film and coating on food items. In the present work, extracted finger millet starch was studied with the aim of developing a thin and flexible food packaging film. From the results, it was observed that the fabricated films had excellent functional properties, including solubility, swelling index, and water vapor permeability, which could eliminate petroleum-based packaging materials, and gives food materials an extra shelf life, and improve overall food quality.

Modelling of arsenic (III) removal from aqueous solution using film theory combined Spiegler-Kedem model: pilot-scale study.

Arsenic contamination in drinking water is recognized as major health hazard worldwide. As reported in literature, more than 19% Indians are consuming lethal levels of arsenic for drinking purposes. In this work, arsenic (III) removal was studied using HFN300 polyethersulfone nanofiltration membrane in spiral wound configuration. Various membrane parameters such as hydraulic permeability (4.87 L m-2 h-1 bar-1), mass transfer coefficient (0.957*10-6 m s-1), reflection coefficient (0.9), and solute permeability (2*10-9 m s-1) were estimated using film theory combined Spiegler-Kedem (FTCSK) model. The higher value of reflection coefficient suggested the impervious nature of nanofiltration (NF) membrane used for arsenic (III) solute rejection. The influence of various operating parameters such as transmembrane pressure, initial feed concentration, and feed flowrate on membrane performance was also examined. It was found that arsenic (III) rejection was dependent on pressure and feed concentration. Result showed that more than 96.4% arsenic (III) rejection was achieved for 50 mg L-1 of feed at optimized conditions. As HFN300 membrane was negatively charged at pH 8 and arsenic (III) was available in neutral solute form, electro-migration was not considered for solute rejection mechanism. Solution diffusion with significant coupling between solute and solvent, steric hindrance effect, convection, and solute-membrane affinity interactions were considered dominant factors for the possible solute rejection mechanism. Rejection efficiency (% R) and permeate flowrate (Q2) were simulated and compared with experimental results. It was found that simulated results were in excellent agreement with the experimental results. The maximum error obtained was within 10% for both % R and Q2. This confirms the efficacy of FTCSK model in predicting arsenic (III) removal using NF membrane. The annualized cost per cubic metre of treated water was estimated as 3.32 $/m3. This further confirms the feasibility of using NF process in removing arsenic from contaminated water.

Thermal decomposition kinetics and properties of grafted barley husk reinforced PVA/starch composite films for packaging applications.

Thermal degradation kinetics was performed on thermogravimetric (TGA) curves of crosslinked PVA/starch composite films reinforced with barley husk (BH) and grafted BH (using lauric acid) obtained by heating samples in an inert atmosphere with different heating rates (5, 10, 15 and 20 °C/min). The activation energy for composite films was determined using Flynn-Wall-Ozawa (FWO) Kissinger-Akahira-Sunose (KAS), Friedman (FR) and modified Coasts Redfern (CR) methods. The results showed that activation energy for thermal degradation of grafted BH composite film was higher than of BH. Incorporation of grafted BH into crosslinked PVA/starch matrix improved the mechanical performance of the films compared to BH and showed 30 % increase in tensile strength after reinforcement. Grafted BH composite films showed higher barrier properties for light, water vapor and oxygen as required for packaging applications. Biodegradability of the films improved significantly after incorporation of BH into the polymer matrix and showed 70 % degradation after 180 days.

Effect of cross linking of PVA/starch and reinforcement of modified barley husk on the properties of composite films.

Barley husk (BH) was graft copolymerized by palmitic acid. The crystalline behavior of BH decreased after grafting. Poly vinyl alcohol (PVA)/starch (St) blend film, urea formaldehyde cross linked PVA/St films and composite films containing natural BH, grafted BH were prepared separately. The effect of urea/starch ratio, content of BH and grafted BH on the mechanical properties, water uptake (%), and biodegradability of the composite films was observed. With increase in urea: starch ratio from 0 to 0.5 in the blend, tensile strength of cross linked film increased by 40.23% compared to the PVA/St film. However, in grafted BH composite film, the tensile strength increased by 72.4% than PVA/St film. The degradation rate of natural BH composite film was faster than PVA/St film. Various films were characterized by SEM, FT-IR and thermal analysis.

Persistent sex difference in hospital outcome following percutaneous coronary intervention: results from the New York State reporting system.

BACKGROUND: Although sex-related differences in early outcomes have been observed in young women following acute myocardial infarction (AMI) and coronary bypass surgery, evidence for similar differences following percutaneous coronary intervention (PCI) is lacking. METHODS: Using the 1999 to 2002 New York State PCI reporting system, we identified 11,162 men and 2,561 women aged 50 years or younger undergoing a first PCI procedure. In-hospital outcomes were compared by gender after multivariable adjustment for baseline, clinical and procedural characteristics. RESULTS: Young women undergoing an initial PCI procedure were more likely to belong to racial or ethnic minorities and exhibit more comorbidities than young men. However, they had better ejection fraction (52.9% +/- 11.3 vs. 51.9 +/- 11; p = 0.0002) and presented more often with single-vessel disease (75% vs. 67%; p < 0.0001). Despite women receiving glycoprotein IIb/IIIa inhibitors (58.6% vs. 65.1%; p < 0.0001) and stents (92.5% vs. 94.9%; p < 0.0001) less often, procedural success was achieved equally (97% vs. 96%). Young women experienced higher rates of in-hospital mortality (0.70% vs. 0.22%; p < 0.0001), and vascular damage (0.82% vs. 0.24%; p < 0.0001) compared to men. In multivariable analysis, female sex independently predicted in-hospital mortality (OR 4.0, 95% CI: 1.9 to 8.1) after adjustment for urgency of PCI, clinical and procedural characteristics. CONCLUSION: A gender-based difference in early survival exists in young women undergoing a first PCI procedure. Further investigation into the mechanism of this higher risk is warranted.