Extraction of lipid-soluble antioxidants from rosemary leaves using vegetable oils

The objective of this research was to extract carnosic acid and carnosol, natural lipid-soluble antioxidants, from rosemary leaves without the use of chemical aid. Three different vegetable oils [high oleic soybean oil (HOSO), peanut oil (PO) and cottonseed oil (CO)] were used as the medium for extracting rosemary's lipid-soluble antioxidants. Dried rosemary leaves were ground into fine particles, added two of the selected vegetable oils, mixed and heated. The vegetable oil containing the extracted antioxidants was filtered from the rosemary particles and analysed using high-performance liquid chromatography (HPLC). As a control, a common extraction method using ethanol was performed to compare the oil extraction efficiency for carnosic acid and carnosol. HPLC analysis confirmed the presence of carnosic acid and carnosol in all three vegetable oil solutions. Compared to the ethanol extraction, a higher level of the carnosic acid was found in the vegetable oil solutions. Among the vegetable oils, high oleic soybean oil contained the most carnosic acid; however, there were similar amounts of carnosol in all three vegetable oil solutions. The extractions' efficacy was tested on soybean oil's (SO) oxidative stability by adding 2% (w/w) of the antioxidant–vegetable oil solution. The results obtained from peroxide value (PV) and p-anisidine value (AnV) analysis documented a significantly lower degree of oxidation in the soybean oil containing the extracted antioxidant solutions, compared to the pure soybean oil.     

Comparison between lipid and protein oxidation progress in the tail and claw muscles of signal crayfish (Pacifastacus leniusculus)

Microbial activity and then oxidation progress are the most important freshness indicators during post-mortem. In this study, we monitored proteomic and microbial changes, as well as biochemical degradation, in the tail and claw muscles of crayfish stored for 12 days at +4 °C. One specified protein band at 107 kDa in the claw muscle and two specified protein bands in the tail muscle at 140 and 36–40 kDa were identified. Western blotting indicated a higher amount of oxidised proteins in the tail compared to the claw muscle. Tail muscle showed higher oxidation progress and calpain activity than claw one. Both muscles were spoiled after 12 days with respect to total viable counts. In the first days, calpain activity is the main reason for protein degradation, while protein oxidation dominates for the rest of the time. Lipid–protein oxidation progress showed probably, protein oxidation started earlier than lipid oxidation in both muscles.     

酸性材料在CVOCs催化氧化中的应用

含氯挥发性有机化合物(CVOCs)对环境安全和人类健康存在持久性污染和危害。催化氧化法具有操作温度低和CO_2选择性高等优点,被广泛应用于CVOCs催化降解。催化剂作为CVOCs催化降解过程的核心部分,受到很多学者的关注。分析酸性分子筛、金属改性分子筛和复合氧化物酸性材料对各种CVOCs催化氧化活性、副产物控制性能、CO_2和HCl选择性的影响。结果表明,催化剂表面酸中心、氧化中心和催化剂表面结构性质在CVOCs催化氧化过程中起重要作用。较多酸中心和较大比表面积有利于CVOCs分子的吸附和活化,提高HCl选择性。而较多氧化中心则有利于CVOCs深度氧化,减少副产物产生,提高CO_2选择性。     

挥发性有机化合物催化氧化技术

基于环境友好,对使用催化氧化法去除挥发性有机化合物(VOCs)的原理、特点以及催化剂、工艺流程等研究进行综述。挥发性有机化合物完全催化氧化机理分为:Mars-van Krevelen(MVK)模型、Langmuir-Hinshelwood(L-H)模型和Eley-Rideal(E-R)模型。复合金属氧化物催化剂是研究的热点,去除VOCs的核心是使反应温度降低,即具有低温和高活性的催化剂。延长催化剂寿命、提高去除效率也可以带来良好的节能效果和降低投资成本。对于低浓度和大体积VOCs排放,可通过吸附+催化混合法先进技术实现去除,且成功应用于实践。     

Evolution mechanism of active groups and thermal effects of Chinese lignite in low-temperature oxidation

Abstract

The evolution of active groups at low temperature was examined using Chinese lignite by infrared technology and X-ray photoelectron spectroscopy (XPS). The results showed that the hydroxyl, aliphatic ether, methylene, and methyl groups played important roles in the low-temperature oxidation of lignite below 200?°C. Carbonyl and carboxyl groups were important intermediates. Thus, a multi-step evolution mechanism involving the hydroxyl, aliphatic ether groups, and alkane was reasoned to describe the low-temperature oxidation of lignite. In addition, according to the oxidation kinetics experiment and the evolution laws of the active groups, the ratios of the reaction lines were determined considering the accuracy of thermal effects. The thermal effects and the heat release intensities of each temperature interval were obtained based on the evolution mechanism and the reaction ratios. The shortest spontaneous combustion period of lignite was calculated and compared with the experimental value, which proved that the reasoned evolution mechanism of the active groups and the calculations of the thermal effects were reliable.     

An isothermal oxidation behaviour of atmospheric plasma and high-velocity oxy-fuel sprayed nickel based coating

This paper describes the isothermal oxidation behaviour of NiCrBSiFe coatings on SS 316 L deposited by the atmospheric plasma (APS) and high-velocity oxy-fuel (HVOF) processes. As-sprayed coatings were oxidised isothermally in the air at 900 °C temperature for 1000 h. The thermogravimetric analysis was performed to measure the oxidation rate. The coating and oxide scale characterisation was carried out using SEM, EDAX, XRD, porosity analysis, and nanoindentation. The HVOF sprayed NiCrBSiFe coating shows better oxidation resistance than the APS coating, due to high density, less porosity, and formation of more protective oxide scale.     

Phosphatized pseudo-core-shell Ni@Pt/C electrocatalysts for efficient hydrazine oxidation reaction

In this study, a series of phosphatized pseudo-core-shell Ni@Pt/C electrocatalysts has been obtained for efficient hydrazine oxidation reaction (HzOR). These (Ni@Pt–P/C) electrocatalysts were prepared by a primary replacement method followed by subsequent phosphating process. Among all Ni@Pt–P/C electrocatalysts, as-prepared Ni@Pt–P/C-400 electrocatalyst shows the highest HzOR performance (515 mA mg⁻¹_Pt), best stability, durability and lowest activation energy (12.60 kJ mol⁻¹). The satisfactory HzOR performance is mainly resulted from the unique design of phosphating effect on core-shell structure which producing good synergistic effect between Ni, P and Pt. This work would pave a way for developing other low-Pt catalysts in the future.     

OMS-2催化剂成型工艺研究及其在印染废水处理中的应用

以OMS-2粉体催化剂为基础,对催化剂进行挤出成型,考察粘结剂种类、粘结剂用量、润滑剂和孔结构改进剂用量、焙烧温度对成型催化剂机械强度的影响。得到最佳成型工艺条件为,粘结剂硅溶胶用量为OMS-2粉体催化剂质量的105%～110%、辅助粘结剂纳米ZrO_2用量为OMS-2粉体催化剂质量的30%～35%、润滑剂田菁粉用量为OMS-2粉体催化剂质量的2. 5%～3. 0%、孔结构改进剂柠檬酸用量为OMS-2粉体催化剂质量的5%～6%,焙烧温度450℃。成型后催化剂机械强度可达150 N·cm~(-1),满足工业化应用对催化剂强度的要求。将成型催化剂应用于催化湿式氧化印染废水处理,经过432 h活性评价时间,COD平均去除率约91. 6%,反应结束后催化剂结构完整,平均机械强度约144 N·cm~(-1),表现出良好的水热稳定性。