Functionalized Dipicolinic Acid Derivatives as TALSPEAK-MME Stripping Agents

ABSTRACT

This work describes the results of an assessment of two derivatives of dipicolinic acid (DPA) as the actinide-selective stripping reagents in the combined HEH[EHP]/Cyanex-923 system, TALSPEAK-MME (mixed monofunctional extractants). One purpose of this investigation is to demonstrate probable advantages derived in phase-transfer kinetics by deploying dipicolinates as preorganized aminopolycarboxylate complexants in TALSPEAK-derived separation systems. The investigation is focused on the behavior of the lanthanides, Am, and selected transition metals (Zr, Mo, Pd, Ru, and Rh) in the extraction, solvent conditioning, and stripping steps. Solvent conditioning with glycine buffer solutions is shown to be effective for the removal of entrained HNO₃ while also managing Pd concentration prior to actinide stripping. The efficacy of the DPA derivative during the actinide-selective strip was assessed, focusing explicitly on the effects of pH and ligand concentration and evaluating the stripping kinetics. These ligands were shown to be highly selective for americium, producing in the TALSPEAK-MME platform separation factors comparable to commonly used actinide selective stripping agents for radiotracer Eu, Am, a trans-lanthanide series and selected transition metals. The stripping kinetics study revealed very rapid phase-transfer reactions, reaching equilibrium in less than 10 s on vigorous agitation. Further work will be required to address the possible contamination of the product by selected transition metals (such as Zr) during the stripping step.     

The alginate fermentation strain Pantoea sp. F16-PCAi-T3P21 and ethanol production

Bio-ethanol production from algae is a promising way to help solve the energy problem. Alginate is a major component of algae, but it cannot be utilized by existing ethanol fermentation microorganisms. In order to improve the utilization rate of brown algae, high alginate fermentation strains should be obtained. In this research, strains for algae fermentation were got from several experiments. The ethanol yield of strain A was the highest, which was 0.095 g/g (ethanol to alginate). The identification of strain A was carried out and it was 99% identical to Pantoea sp. F16-PCAi-T3P21. Fermentation experiments with different substrates were carried out, such as laminaran, mannitol, L. japonica and acid hydrolysate of L. japonica, and the ethanol yield rate of L. japonica acid hydrolysate was the highest, which reached 0.17 g/g ethanol to L. japonica. It showed that strain A can converse alginate to ethanol in a relatively high yield rate, and might be a promising strain with L. japonica as the substrate, we believe more research should be carried out on this strain.     

Effect of different fibres on texture,rheological and sensory properties of acid casein processed cheese sauces

The objective of this study was the evaluation of different fibres (bamboo, acacia, potato or citrus) addition on texture, rheological and sensory properties of acid casein processed cheese sauces. Fibres used in production of sauces had an impact on the texture, viscosity, viscoelastic and sensory properties. The largest increase in viscosity was observed in products with addition of potato fibre, which have good water holding and adsorption capacity. Processed cheese sauce with the addition of citrus fibre was characterised by the highest values in general, and the increase of this feature in the tested samples was regular. Adhesiveness was the highest in products with 1% addition of every fibre. The lowest values of viscosity single shear, G′ and G″ moduli, among all tested, had sauces with acacia fibre. Moreover, they had the most thin liquid consistency, which was different from preferred one.     

Synergistic effect on hydrolytic sodium borohydride adding waste Al for hydrogen generation

Synergistic effect of sodium borohydride (NaBH₄) mixed with waste aluminum in hydrolytic system were investigated to improve the hydrogen generation (HG) efficiency. The alkaline aqueous originated from NaBH₄ hydrolysis impels the passive aluminum hydroxide film of Al surface to be dissolved, thus, mutual effect of HG amount increasing by 88% and 50% for Al powder and waste Al can, respectively. To add acid catalyst in the mutual mixture system prompts to significantly accelerate HG rate from 100 ml/min˙g to 400 ml/min˙g but raising temperature is not obviously found. It is speculated that exothermic effect dominates the NaBH₄ hydrolytic reaction and eliminates the temperature effect. In this study, the mutual hydrolyzed reaction of NaBH₄ and waste Al provides ecofriendly environment, low cost and enables to achieve higher HG rate and further uses for portable/mobile fields.     

Investigation on slag fiber characteristics: Mechanical property and anti-corrosion performance

Inorganic fiber shows good insulation performance in civil construction and industry insulation. In the present paper, tensile strength of slag fiber produced with molten blast furnace slag was investigated systematically with the Weibull distribution theory in comparison with glass and basalt fibers. It was found that the mean tensile strength reached 2578.60 MPa and the shape parameter m in Weibull distribution is 2.4494, which indicates a lower uniformity. Anti-corrosion performances were also studied by means of the mass and strength loss after acid and alkaline solution treatment. Furthermore, SEM and FTIR were used to analyze the structural characteristics of original and treated fibers. This work has proved that the H⁺ and OH⁻ can both break the Si–O bond and then lead to the movement to high wavenumber for the bands of the symmetric stretching vibrations of [SiO₄]-tetrahedra. The anti-corrosion results indicated that slag fibers could not be used in acid environment, while its anti-alkali performance is relatively excellent compared with glass and basalt fibers.     

A mineralogical approach to evaluating laboratory scale acid rock drainage characterisation tests

Effective management of the risks associated with acid rock drainage (ARD) requires the ability to identify material with a potential to generate ARD reliably. With the increasing prevalence of quantitative mineralogy (Quantitative XRD, auto-SEM), opportunity exists to use mineralogy at all stages in ARD characterisation and prediction. This study uses a mineralogical approach across the head grade samples and the residues obtained under leach conditions of several common ARD characterisation tests (Acid Neutralising Capacity, Net Acid Generation), as well as the University of Cape Town (UCT) biokinetic test to evaluate the extent to which acid-neutralising minerals react. The results show the contribution of the carbonates to the acid neutralising capacity, as well as the partial dissolution of intermediate weathering silicate minerals such as chlorite and mica.     

Impact of bioethanol impurities on steam reforming for hydrogen production: A review

Hydrogen fuel cells (H₂–FCs) are promising devices for pollution-free and efficient power production. Renewable H₂ from biomass is often produced through catalytic ethanol steam reforming (ESR), which requires a steam/ethanol molar ratio of at least three. The bioethanol obtained by biomass fermentation contains large amounts of water and can be directly subjected to ESR without complex purification steps. However, a wide spectrum of impurities is present in such bioethanol samples, thus complicating the ESR process. Acetic acid, fusel alcohols, ethyl acetate, and sulfur components have been reported as important bioethanol impurities, and also as the main precursors of carbon deposits on the ESR catalyst. On the other hand, amines, methanol, and aldehydes, which are minor bioethanol impurities, have been reported to enhance the H₂ production. This review seeks to define alternatives to reduce the above negative impurities and increase the positive ones during biomass pretreatment and fermentation. Additionally, ESR catalysts are reviewed to identify the features that make them more resistant to deactivation. The combination of strategies to control the impurities during biomass pretreatment, fermentation, purification and the development of highly resistant catalysts may allow processes to produce H₂ from biomass with a low carbon footprint, rendering H₂–FCs an environmentally friendly technology for power production.     

腐蚀环境下异质自冲铆接头静力学性能研究

为研究钢铝异质自冲铆接头在盐腐蚀和酸腐蚀中静力学性能的变化,对DP590-5052自冲铆试件进行干湿周浸加速腐蚀实验,通过腐蚀动力学和静力学测试分析不同腐蚀时间接头的失重量、失效模式和静失效载荷性能。结果表明,盐腐蚀环境中钢铝试件(YDA)组失重量呈现上升趋势,腐蚀速率则逐渐减小;酸腐蚀(SDA)组试件失重量先上升后下降,腐蚀速率也呈现出相同的趋势。酸腐蚀对接头失效模式影响更为显著。两种腐蚀对接头静强度均有影响,接头对盐性环境的抗腐蚀性能较小。     

Quality and nutritional characteristics of traditional curd cheese enriched with thermo-coagulated acid whey protein and indigenous Lactococcus lactis strain

Consumer interest in a healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand for bio-functional and sustainable dairy foods. Supplementation of curd cheese with thermo-coagulated acid whey protein (TAWP) led to 8–10% higher contents of moisture, 23–31% of lactose, 12–13% of unsaturated, 5–6% of monounsaturated, 63% of polyunsaturated, and 3–4% of long-chain fatty acids. Lipid quality indices – TI, AI, h/H, and Omega 6/3 among others, were also significantly better than those of control cheese. The addition of indigenous Lactococcus lactis strain enhanced the flavour of cheese samples, decreased the counts of yeast and mould up to 1 log cfu g⁻¹ after 10 days of storage. The replacement of curd with TAWP resulted in novel cheese with overall sensory perception above 77 points and added nutritional and functional value, however, body and texture parameters of modified cheese samples require an improvement.