用活化焙烧-硫酸浸出-溶剂萃取法从钴渣中提取硫酸钴的试验研究

研发了一种从钴渣中提取硫酸钴的新工艺,即钴渣活化焙烧-硫酸浸出-溶剂萃取工艺.在活化焙烧温度900 ℃,活化剂添加量2∶1(添加剂与钴渣的质量比),焙烧时间1 h;硫酸浸出液固体积质量比5∶1,硫酸浓度20%,浸出温度90 ℃,浸出时间1.5 h条件下,钴浸出率为98.8%.然后采用P204萃取除杂-P507萃取分离钴、镍工艺得到纯净的高浓度钴溶液,蒸发结晶后得到质量符合HG3-914-78化学纯度要求的硫酸钴.     

Lithium Intercalation Compound Dramatically Influences the Electrochemical Properties of Exfoliated MoS2

MoS₂ and other transition metal dichalcogenides (TMDs) have recently gained a renewed interest due to the interesting electronic, catalytic, and mechanical properties which they possess when down‐sized to single or few layer sheets. Exfoliation of the bulk multilayer structure can be achieved by a preliminary chemical Li intercalation followed by the exfoliation due to the reaction of Li with water. Organolithium compounds are generally adopted for the Li intercalation with n‐butyllithium (n‐Bu‐Li) being the most common. Here, the use of three different organolithium compounds are investigated and compared, i.e., methyllithium (Me‐Li), n‐butyllithium (n‐Bu‐Li) and tert‐butyllithium (t‐Bu‐Li), used for the exfoliation of bulk MoS₂. Scanning transmission electron microscopy (STEM), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) are adopted for a comprehensive characterization of all materials under investigation. In addition, catalytic properties towards the hydrogen evolution reaction (HER) and capacitive properties are also tested. Different organolithium compounds exhibit different extent of Li intercalation resulting in different degrees of exfoliation. The inherent electrochemical behavior of MoS₂ consisting of significant anodic and cathodic peaks as well as its capacitive behavior and catalytic properties towards hydrogen evolution reaction are strongly connected to the exfoliation compound used. This research significantly contributes to the development of large‐scale synthesis of electrocatalytic MoS₂‐based materials.     

Myoglobin/gold nanoparticles/carbon spheres 3-D architecture for the fabrication of a novel biosensor

A novel biosensor based on a myoglobin/gold nanoparticles/carbon spheres (Mb-AuNPs-CNs) 3-D architecture bioconjunction has been fabricated for the determination of hydrogen peroxide (H₂O₂). Cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were used to characterize the bioconjunction of the AuNPs-CNs with Mb. Experimental results demonstrate that the AuNPs-CNs hybrid material is more effective in facilitating electron transfer of the immobilized enzyme than CNs alone, which can be attributed to the unique nanostructure and larger surface area of the bioconjunction. The biosensor displayed good performance for the detection of H₂O₂ with a wide linear range from 0.28 μmol/L to 116.5 μmol/L and a detection limit of 0.12 μmol/L. The Michaelis-Menten constant K _M^app value was estimated to be 0.3 mmol/L. The resulting biosensor exhibited fast amperometric response, and good stability, reproducibility, and selectivity to H₂O₂. This article is published with open access at Springerlink.com     

钨铜化合物氢还原制备钨铜复合粉研究

通过对钨铜化合物氢还原过程进行热力学分析,找到了制备均匀细颗粒钨铜复合粉的热力学途径--彻底快速除去还原系统中的水分.设计了封闭还原系统,用此系统进行氢气热还原,不仅使氢气得到充分利用,而且容易判断反应终点.通过系统内的特殊装置除水,降低了还原温度,在600℃下还原得到了混合均匀的钨铜复合粉.系统能彻底快速除去反应生成的水分,使反应物的湿度大大降低,确保得到细颗粒的钨铜复合粉,其平均粒径小于80nm.     

枪黑色Sn-Ni合金在NaOH溶液中的析氢电催化性能

为了降低电解制氢的电耗,提高经济效益.作者对枪黑色Sn-Ni合金在NaOH溶液中的析氢电流化性能进行了研究.试验测出的电化学参数表明,在NaOH溶液中电解制氢时,枪黑色Sn-Ni合金的析氢电催化性能比45钢和高硫镍的强很多,而且具有很高的电化学稳定性.用它取代目前工业上使用的45钢和高硫镍作为电解制氢的阴极,可显著降低制氢的生产成本.     

地下煤制气制取液化天然气和液氢工艺研究

目的脱除地下煤制气中的酸气,将地下煤制气中的CH₄和H₂分离出来并液化。 方法对常见的分离方法进行对比,确定采用低温精馏法对煤制气进行脱酸气、分离CH₄和H₂并液化。根据低温精馏法的原理,设计了一种全新的地下煤制气脱酸气、分离CH₄和H₂并液化的工艺流程,该工艺主要由两个精馏塔、一个两相分离器和三级氦膨胀制冷系统组成。同时利用HYSYS软件对其进行模拟分析,确定最优参数。 结果该工艺可以将地下煤制气中CO₂的摩尔分数脱除到0,H₂S的摩尔分数脱除到3.65×10-14,满足处理要求。同时可以实现CH₄回收率为99.97%,加压液化天然气(PLNG)的摩尔分数为99.97%,H₂的回收率为98.30%,液氢(LH₂)的摩尔分数为99.99%。 结论该工艺可以有效利用地下煤制气制取PLNG和LH₂,且所需能耗较传统工艺能耗降低了11.64％,具有较高的经济效益。      

生物质气催化合成甲醇的实验研究

为了探索秸秆类生物质转化为燃料甲醇的工艺条件,采用热化学方法将玉米秸秆裂解为秸秆燃气,对该燃气进行优化实验,制备出秸秆合成气.在直流流动等温积分反应器中,使用国产C301铜基催化剂,对催化合成甲醇的反应压力、反应温度、秸秆合成气组成进行优化实验研究.结果表明:合成甲醇的最佳反应温度和反应压力分别为230℃和5 MPa,秸秆合成气适宜组成为10.49%CO,8.8%CO2,40.49%H2,0.95%CnHm,37.32%N2.     

ILB®, a Low Molecular Weight Dextran Sulphate,Restores Glutamate Homeostasis,Amino Acid Metabolism and Neurocognitive Functions in a Rat Model of Severe Traumatic Brain Injury

In a previous study, we found that administration of ILB^®, a new low molecular weight dextran sulphate, significantly improved mitochondrial functions and energy metabolism, as well as decreased oxidative/nitrosative stress, of brain tissue of rats exposed to severe traumatic brain injury (sTBI), induced by the closed-head weight-drop model of diffused TBI. Using aliquots of deproteinized brain tissue of the same animals of this former study, we here determined the concentrations of 24 amino acids of control rats, untreated sTBI rats (sacrificed at 2 and 7 days post-injury) and sTBI rats receiving a subcutaneous ILB^® administration (at the dose levels of 1, 5 and 15 mg/kg b.w.) 30 min post-impact (sacrificed at 2 and 7 days post-injury). Additionally, in a different set of experiments, new groups of control rats, untreated sTBI rats and ILB^®-treated rats (administered 30 min after sTBI at the dose levels of 1 or 5 mg/kg b.w.) were studied for their neurocognitive functions (anxiety, locomotor capacities, short- and long-term memory) at 7 days after the induction of sTBI. Compared to untreated sTBI animals, ILB^® significantly decreased whole brain glutamate (normalizing the glutamate/glutamine ratio), glycine, serine and γ-aminobutyric acid. Furthermore, ILB^® administration restored arginine metabolism (preventing nitrosative stress), levels of amino acids involved in methylation reactions (methionine, L-cystathionine, S-adenosylhomocysteine), and N-acetylaspartate homeostasis. The macroscopic evidences of the beneficial effects on brain metabolism induced by ILB^® were the relevant improvement in neurocognitive functions of the group of animals treated with ILB^® 5 mg/kg b.w., compared to the marked cognitive decline measured in untreated sTBI animals. These results demonstrate that ILB^® administration 30 min after sTBI prevents glutamate excitotoxicity and normalizes levels of amino acids involved in crucial brain metabolic functions. The ameliorations of amino acid metabolism, mitochondrial functions and energy metabolism in ILB^®-treated rats exposed to sTBI produced significant improvement in neurocognitive functions, reinforcing the concept that ILB^® is a new effective therapeutic tool for the treatment of sTBI, worth being tested in the clinical setting.     

Directed Evolution of Phi Class Glutathione Transferases Involved in Multiple-Herbicide Resistance of Grass Weeds and Crops

The extensive application of herbicides in crop cultivation has indisputably led to the emergence of weed populations characterized by multiple herbicide resistance (MHR). This phenomenon is associated with the enhanced metabolism and detoxifying ability of endogenous enzymes, such as phi class glutathione transferases (GSTFs). In the present work, a library of mutant GSTFs was created by in vitro directed evolution via DNA shuffling. Selected gstf genes from the weeds Alopecurus myosuroides and Lolium rigidum, and the cereal crops Triticum durum and Hordeum vulgare were recombined to forge a library of novel chimeric GSTFs. The library was activity screened and the best-performing enzyme variants were purified and characterized. The work allowed the identification of enzyme variants that exhibit an eight-fold improvement in their catalytic efficiency, higher thermal stability (8.3 °C) and three-times higher inhibition sensitivity towards the herbicide butachlor. The crystal structures of the best-performing enzyme variants were determined by X-ray crystallography. Structural analysis allowed the identification of specific structural elements that are responsible for k_cat regulation, thermal stability and inhibition potency. These improved novel enzymes hold the potential for utilization in biocatalysis and green biotechnology applications. The results of the present work contribute significantly to our knowledge of the structure and function of phi class plant GSTs and shed light on their involvement in the mechanisms of MHR.     

新型有机-无机杂化物(TB0.5Zr0.5H0.5PW)催化合成苯甲醛乙二醇缩醛反应

通过离子交换法制备了系列季铵盐锆盐共掺杂磷钨酸催化剂,利用SEM、FT-IR、XRD、XPS、TGA-DTG以及正丁胺电位法等技术手段对催化剂结构、酸度进行表征,并对其催化缩醛反应性能进行研究。考察了催化剂用量、醇醛摩尔比、带水剂量和反应时间对苯甲醛乙二醇缩醛产率的影响。研究表明,TB_0.5Zr_0.5H_0.5PW(TB为四丁基溴化铵)固体酸催化剂具有优异的催化性能,催化剂强的Bronsted酸性、Bronsted与Lewis酸中心间的协同效应及“假液相”特性是该催化剂具有高活性的原因。以TB_0.5Zr_0.5H_0.5PW为催化剂,经响应面优化所得苯甲醛乙二醇缩醛最佳制备工艺条件为：乙二醇与苯甲醛摩尔比1.5:1,TB_0.5Zr_0.5H_0.5PW用量为苯甲醛质量的1.9%,反应时间3 h,带水剂环己烷量12.6 mL,该条件下苯甲醛乙二醇缩醛产率为94.6%。TB_0.5Zr_0.5H_0.5PW固体酸催化剂在重复使用6次后仍然表现出优异的催化性能,表明该催化剂具有较好的工业应用前景。关键词：磷钨酸;季铵盐;缩醛反应;苯甲醛乙二醇缩醛;催化技术 中图分类号：TQ655 文献标识码： A 文章编号：1003-5214 (2020) 01-0000-00