聚乙二醇-硫酸钠-硫氰酸钾体系中Co(Ⅱ)、 Ni(Ⅱ)、 Mo(Ⅵ)的萃取分离研究

用硫氰酸钾作萃取剂，探讨了在聚乙二醇（ＰＥＧ）２０００硫酸钠硫氰酸钾双水相体系中Ｃｏ（Ⅱ）、Ｎｉ（Ⅱ）、Ｍｏ（Ⅵ）等金属离子的萃取行为。控制一定条件，实现了Ｃｏ（Ⅱ）与Ｎｉ（Ⅱ）、Ｃｏ（Ⅱ）与Ｍｏ（Ⅵ）及Ｃｏ（Ⅱ）与Ｎｉ（Ⅱ）、Ｍｏ（Ⅵ）混合离子的定量分离，并研究了不同类型的表面活性剂对ＰＥＧ相萃取行为的影响。     

活性白土生产废酸重复利用工艺研究

在制活性白土时添加ＫＣｌ,使其废酸得以重复利用 。     

The rapid synthesis of nanostructured orthorhombic KNbO3 particles by a microwave-assisted hydrothermal method and their characterization

We studied the molar ratio effects of niobium and potassium precursors on the structure and morphology of potassium niobate powders prepared via microwave-assisted hydrothermal synthesis (MaHS). KNbO₃ nanostructures in the form of nanotowers and nanocubes were obtained at reduced synthesis times (30–240 min). The products were characterized via XRD, Raman spectroscopy, SEM, and TEM; band gap calculations used diffuse reflectance data. The results indicate that KNbO₃ nanostructures were obtained with crystallite sizes ranging from 33 to 52 nm. An orthorhombic crystalline structure was formed from the increase of KOH at a molar ratio Nb₂O₅:KOH (1:8 to 1:16 M). The band-gap of 3.1–3.3 eV has potential use in photodegradation applications.     

微波消解法快速测定废水中的总磷

采用微波对废水中的总磷进行消解,考察了消解时间、功率等不同实验条件对标样微波消解的影响,得出本实验消解的最佳条件,即过硫酸钾溶液用量为 0.5 mL,压力为10 MPa,消解时间为 2 min：并将该法与总磷测定的常规方法进行了比较,结果表明,过硫酸钾-微波消解法操作简单,效率高,对工作环境污染小.最后对微波消解法的精密度和准确度进行验证,实验结果表明其具有良好的精密度和准确度.     

Enhanced piezoelectric property and promoted depolarization temperature in Fe doped Bi1/2(Na0.8K0.2)1/2TiO3 lead-free ceramics

Piezoelectric sensors and energy harvesters require piezoelectric materials with large piezoelectric responses and good thermal stability. However, a commonly accepted concept is that the promotion of depolarization temperature of Bi_1/2Na_1/2TiO₃-based lead-free ceramics is usually companied by deterioration of piezoelectric properties. In the present study, the effects of acceptor-Fe doping on piezoelectric property and thermal depolarization behavior of Bi_1/2(Na_0.8K_0.2)_1/2TiO₃ ceramics are investigated. Fe doping at an appropriate level (≤ 3.0%) improves piezoelectric property and thermal stability simultaneously, due to the stabilization of long-range ferroelectric order. Piezoelectric constant d₃₃ increases from 125 pC/N to 148 pC/N with Fe amount of 3.0%, and then decreases. The depolarization temperature T_d is promoted continuously with Fe addition, from 76 °C for the undoped sample to 118 °C for the sample with Fe amount of 5.0%. It is proposed that the piezoelectric property and thermal stability can be simultaneously improved by stabilizing the long-range ferroelectric order in Bi_1/2Na_1/2TiO₃-based systems with obvious relaxor character. This work provides a new insight into the improvement of Bi_1/2Na_1/2TiO₃-based lead-free piezoelectric ceramics.     

Benign and efficient preparation of thioethers by solvent-free S-alkylation of thiols with alkyl halides catalyzed by potassium fluoride on alumina

The preparation of thioethers by S-alkylation of various thiols with alkyl halides under solvent-free reaction conditions using potassium fluoride on alumina (KF/Al₂O₃) as a solid catalyst has been investigated in detail with respect to three different modes of reaction activation (ultrasound irradiation, microwave irradiation, and conventional heating) for obtaining maximum yield of the thioether. The importance of KF/Al₂O₃ as a particularly efficient catalyst was corroborated for all three modes of reaction activation, although the reaction time was found to be strongly dependent on the mode of activation. The yield of the thioethers was also found to depend on the amount of the solid catalyst relative to the equimolar amounts of the two reactants.     

Potassium promoted Ru/meso-macroporous SiO2 catalyst for the preferential oxidation of CO in H2-rich gases

A series of potassium promoted Ru/meso-macroporous SiO₂ catalysts were prepared and used for the preferential oxidation of CO (CO-PROX) in H₂-rich gases. The catalysts were characterized by using techniques of TEM, SEM TPR, XPS, and N₂ adsorption/desorption. The catalytic activity of Ru/meso-macroporous SiO₂ was markedly improved by the introduction of potassium. The catalyst of K-5 wt.% Ru/meso-macroporous SiO₂ with molar ratio of K:Ru = 5:7 exhibited relatively high activity and selectivity for CO-PROX. Nanoparticles of ruthenium species can be highly dispersed on the meso-macroporous SiO₂ support by the simple impregnation method. The addition of potassium weakened the interaction between metallic Ru and the silica support. Lowering the reduction temperature of ruthenium ions could keep ruthenium in the state of metallic Ru, and it was proposed that potassium acted as an electron donating agent. The electron donating effect of potassium improved the low temperature activity for CO oxidation and increased the selectivity of O₂ for CO oxidation, thus K-modified Ru/meso-macroporous SiO₂ catalyst showed obviously a wide temperature window for CO elimination from H₂-rich gases, meanwhile the related mechanism was discussed.     

低钾胁迫对大豆叶片膜脂过氧化及保护酶活性的影响

以在大田筛选的钾高效型大豆品种沈农6号和钾低效型品系铁95068-5为试材,研究了不同供钾水平对大豆膜脂过氧化作用及保护酶活性的影响。试验结果表明,随着钾浓度的降低,2个品种在各生育时期的相对电导率和MDA含量均有所增加,但沈农6号增加幅度不大,而铁95068-5则增幅较大。在每个生育时期,2个品种各保护酶活性均随着钾浓度的降低而增强,说明适度低钾胁迫会激发大豆的保护酶活性;不同钾浓度下,沈农6号和铁95068-5叶片SOD活性均随着大豆的生长发育逐渐下降;CAT和POD活性先逐渐增强,随后下降：2个品种CAT活性到开花盛期（R2）达到峰值,POD活性分别在鼓粒期（R6）和盛荚期（R4）达到峰值。沈农6号各生育时期SOD、CAT和POD活性均高于同期的铁95068-5,表明大豆钾效率的高低与其体内保护酶系统对活性氧的清除能力直接相关。     

改性竹炭对水溶液中Cu(Ⅱ)、Cd(Ⅱ)的吸附性能

采用不同方法对竹炭进行改性,寻求吸附效果最好的改性产品,并研究其对溶液中Cu2+、Cd2+的吸附性能,考察了吸附时间、溶液pH值、吸附温度和溶液初始浓度对吸附效果的影响,同时与未改性竹炭的吸附性能进行了对比。实验结果表明:相同条件下,氧化改性竹炭对Cu2+、Cd2+的吸附效果明显优于其他方法改性竹炭和未经改性的竹炭。吸附温度为15℃、25℃、45℃时,氧化竹炭对Cu2+的最大吸附量分别为6.653mg/g、6.702mg/g和7.897mg/g,而氧化竹炭对Cd2+的最大吸附量分别为1.700mg/g、1.826mg/g和2.282mg/g。氧化改性竹炭对Cu2+、Cd2+的吸附均符合Freundlich方程和Langmuir方程。实验证明,氧化竹炭是一种应用前景广泛的重金属离子吸附剂。     

A NEW TECHNOLOGY FOR THE CRYSTALLIZATION OF DEAD SEA POTASSIUM CHLORIDE

The aim of this article is to introduce a new technology for the production of Dead Sea potassium chloride. The new technology depends on using the power of ultrasound waves during a crystallization process to enhance potassium chloride precipitation and to improve the end-use properties of the produced crystals. This environmentally clean technology, which is called sonocrystallization, has received very intensive research in the past few years. It was used in this study to modify the crystallization process of potassium chloride from the decomposition of Dead Sea carnallite. Two crystallization runs were done; the first was performed without the application of ultrasound waves and the second was performed with this application. The effect of sonication on the crystallization process time and on crystal size distribution as well as on the purity of the crystals was studied. It was found that the required time for the un-sonicated process was about 150 min. This time was reduced to about 50 min when sonication was applied. The produced crystals were sieved, and the crystal size distribution (CSD) was determined for the two runs. For the sonicated process, finer but more uniform crystals were obtained with a mean average size of 0.2643 mm in comparison with 0.5727 mm for the un-sonicated process. The produced crystals were found to be of 96.07% KCl for the un-sonicated process and this purity was improved to 97.31% KCl by the application of ultrasound waves. Based on the results of this study, it seems to be feasible and economical to scale up the proposed technology for industrial applications.