Adsorption efficiency and photocatalytic activity of fly ash-based geopolymer foam mortar

Fly ash-based geopolymer foam mortar (GFM) was used as an adsorbent material to methylene blue (MB) and also the dye removal material using the photocatalytic mechanism. The GFM, containing 50 wt% river sand aggregate, was prepared to have approximately 46% open porosity, pore size distribution between 0.01 and 3.5 mm, and water permeability of 0.2 cm/s. The variation of adsorption efficiency and adsorption capacity with the contact time of the GFM was first evaluated using various GFM dosages (10, 20, 50, 80, and 100 g/L). The adsorption efficiency at equilibrium (AE_e) was found to linearly increase, while adsorption capacity (q_ae) exponentially decayed, with an increase of loading dosages. The photocatalytic removal efficiency of ~100% was obtained with 50, 80, and 100 g/L GFM loading dosages, with a shorter time at higher dosages. The GFM could be reused, without regeneration, for 5 cycles. The AE_e and q_ae for each reused cycle did not noticeably change suggesting the reusability. The photocatalytic removal efficiency, however, was found to decrease with an increase of the reused cycle. After the 5^th cycle, the highest removal efficiency was reduced to ~70%. The attempts to treat the GFMs with hydrochloric (HCl) and phosphoric (H₃PO₄) acid to reduce the excess alkaline did not give satisfactory results as expected. The photocatalytic removal efficiency had subsided after the treatment with both acids.     

新造珠江大桥主梁0#块施工技术

本文介绍了广州新造珠江大桥的主梁0#块施工情况，针对0#块分支架、挂篮施工相结合的施工方法做出了主要阐述，突出了其与传统施工方法的差异，强调了临时索、挂篮提前应用的先进性和优势，希望对以后类似的斜拉桥主梁0#块施工提供借鉴。     

Cloud Point Extraction and Spectrophotometric Determination of Sulfide in Water Samples using Ethylene Blue Formation Reaction

Abstract

A rapid, selective, and sensitive cloud point extraction process using mixed micelle of a nonionic surfactant, Triton X-114, and an anionic surfactant, SDS, to extract sulfide from aqueous solutions was investigated. The method is based on the color reaction of sulfide with N,N-diethyl-p-phenylenediamine (DPD) in the presence of suitable oxidizing reagent (Fe³⁺) in acid media and cloud point extraction of ethylene blue (EB) dye. Various factors and optimal extraction and reaction conditions like: acid, Fe³⁺, reagent, and surfactant concentration were studied and the analytical characteristics of the method (e.g., limit of detection, linear range, RSD%) were obtained. Linearity was obeyed in the range of 1–100 ng mL^?1 of sulfide ion. The detection limit of the method is 0.5 ng mL^?1 of sulfide ion. The interference effect of some anions, cations, and neutral species was also tested. The method was applied to the determination of sulfide in spring, river, and waste water samples.     

Bathochromic and stabilising effects of sugar beet pectin and an isolated pectic fraction on anthocyanins exhibiting pyrogallol and catechol moieties

The formation of anthocyanin–metal chelates, exhibiting intense blue colours was monitored over a period up to 10 weeks. Evaluating normalised absorption spectra in the range of 580–700 nm and their proportion of the total area under the curve (AUC), provided information about the blue colour hue, intensity and stability. Colour stability in model solutions containing commercial sugar beet pectin or an isolated pectic polysaccharide fraction (PPF) therefrom, both being naturally enriched in aluminium and ferric ions, was assessed in a pH range of 3.6–7.0. The pectic structures stabilised anthocyanin–metal chelates, and thus blue colours by efficiently preventing complex precipitation. Highest bathochromic shifts and most intense blue colours were observed in PPF model solutions containing delphinidin-3-glucoside (Dpd-3-glc), exhibiting a pyrogallol moiety in the flavylium B-ring, compared to cyanidin- (Cyd-3-glc) and petunidin-3-glucoside (Pet-3-glc), both carrying a catechol substituted B-ring. Hue and intensity of the blue colour at pH 5.0 were only insignificantly influenced by the buffer system except for citrate and phosphate buffers, which both annihilated anthocyanin–metal chelate formation. The blue colours faded following first order kinetics. Best stabilities as deduced from storage experiments performed at 20 ± 2 °C in the dark were observed for Dpd-3-glc. In contrast, Cyd-3-glc displayed shortened half-life values, whereas blue Pet-3-glc chelates decomposed rapidly. These results demonstrate that the solubilisation of anthocyanin–metal chelates by pectic structures is a promising option for developing water soluble natural blue food colourants.     

特种电机轴Cr17Ni2钢的兰脆

本文介绍了Cr17Ni2特种电机轴高温时出现的兰脆现象，并对兰脆断口进行了扫描电镜分析。     

利用标志法研究钒—硅酸锆蓝色颜料的生成机理

标志法用来研究钒-硅酸锆蓝色颜料形成过程中的离子移动问题，借此了解该颜料的生成机理。结果表明Si^4 和Zr^4 中Si^4 是唯一可以移动的离子；NaF的加入有利于SiO2的玻璃化，因而对硅离子的迁移有一定贡献，但其移动更依赖于NaF和NH4VO3反应所形成的液相。此外，ZrO2的溶解也是硅酸锆生成的一个限制因素。     

Synthesis of Metal Oxides@C (Metal =Ni,Fe) Based Prussian Blue Analogs as a High-performance Anode Material for Lithium-ion Battery

Ni3[Fe(CN)6]2 nano-cubic precursors were prepared by chemical coprecipitation at room temperature with nickel acetate and potassium ferricyanide as raw materials.The corresponding NiFe2O4-NiO@C composites with excellent crystallization were prepared by two-stage oxidation at low temperature.The microstructure and electrochemical behavior of the materials showed that the Prussian blue analog was transformed into metal oxide while the carbon coating was maintained in the two-stage oxidation at low temperature.The existence of the carbon coating reduces the charge transfer impedance to 31.5 Ω.At the current density of 500 mA/g,the reversible capacity of 632.7 mAh/g is maintained after 500 cycles.At the same time,carbon cladding can also enhance the role of pseudocapacitance in the material.At the scanning rate of 0.1 mV/s,the pseudocapacitance account for 54.4％ of the total discharge capacity,which is significantly higher than that of uncoated materials.     

沙柳基磁性多孔炭的制备及其吸附亚甲基蓝性能研究

采用水热法原位改性沙柳生物炭制备磁性多孔炭复合材料,利用SEM、XRD、FT-IR、XPS和BET分别对多孔炭的形貌、结构表征,并研究磁性多孔炭吸附去除废水中亚甲基蓝性能。系列表征分析结果表明磁性复合材料表面疏松多孔,比表面积为63.01 m²/g,含有-COOH、-OH等丰富的官能团。在亚甲基蓝初始质量浓度为50 mg/L、初始pH值为11,投加量为2 g/L、25℃吸附120 min时,亚甲基蓝的吸附率可达88.52%,最大吸附量为218.08 mg/g;吸附过程与Langmuir吸附等温模型拟合较好,符合准二级吸附动力学模型。吸附以化学吸附为主,吸附稳定,无二次污染,吸附剂廉价易得,便于分离,是理想的亚甲蓝废水处理试剂。