Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH4 from its Hydrolytic Product

Sodium borohydride (NaBH₄) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H₂ at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH₄ with high yield and low costs. The hydrolytic product NaBO₂ in aqueous solution reacts with CO₂, forming Na₂B₄O₇?10 H₂O and Na₂CO₃, both of which are ball‐milled with Mg under ambient conditions to form NaBH₄ in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH₂, bypasses the energy‐intensive dehydration procedure to remove water from Na₂B₄O₇?10 H₂O, and does not require high‐pressure H₂ gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH₄ regeneration and hydrolysis, enabling a wide deployment of NaBH₄ for hydrogen storage.     

Synthesis and characterization of electrically conducting polymers for regenerative engineering applications: sulfonated ionic membranes

Conductive polymers have found extensive application in fuel cells, sensors and more recently as scaffolds for tissue and organ regeneration. Scaffolds that can transmit electrical impulses have been shown to be beneficial in regeneration of tissues like muscle and nerve that are electroactive in nature. Most cellular events and cell functions are regulated by ion movement, and their imbalance is the cause of several diseases. We report synthesis and characterization of sulfonated polymers of poly(methyl vinyl ether‐alt‐maleic anhydride) (PMVEMA), poly(ether ether ketone) (PEEK), poly(ether sulfone) (PES) and poly(phenylene oxide) (PPO) and evaluate their potential for tissue regeneration. The ionic conductive property stems from the presence of sulfonic groups on the polymer backbone. The structure of the polymer was confirmed using Fourier Transform Infrared Spectroscopy and membrane hydrophicity was determined by water contact angle measurement. The electrical conductivity of these sulfonated membranes was found to be 53.55, 35.39 and 29.51 mS/cm for SPPO, SPEEK and SPMVEMA, respectively. The conductivity was directly proportional to the sulfonic acid content on the polymer backbone. The ionic membranes namely SPPO, SPEEK and SPMVEMA demonstrated superior cell adhesion properties (~7–10 fold higher) than cells seeded onto tissue culture polystyrene. The sulfonated membranes exhibited static water contact angle in the range of 70–76°. The membranes supported the proliferation of human skin fibroblasts over 14 days in culture as evidenced by confocal and electron microscopy imaging. The ionic materials reported in this study may serve as scaffolds for a variety of tissue healing and drug delivery applications. Copyright © 2014 John Wiley & Sons, Ltd.     

Enzymatic Preparation of Coniferaldehyde from Coniferyl Benzoate ex. Siam Benzoin

Siam benzoin is a natural resin that contains up to 65% of coniferyl benzoate. Treatment of this material with an esterase followed by an alcohol dehydrogenase in a one-pot procedure gave 1.5 g/L coniferaldehyde in 36% molar yield. Several lipases and esterases were tested, but only pig liver esterase gave significant results. Various alcohol oxidases and alcohol dehydrogenases were screened for their ability to oxidize coniferyl alcohol to coniferaldehyde. Horse liver alcohol dehydrogenase coupled with a cofactor regeneration system was the most efficient of the enzymes tested.     

激淋降膜蒸发多效紧凑式海水淡化装置的研究

基于降膜蒸发与降膜凝结机理,设计建造了一台具有三效回热性能的紧凑式小型海水淡化装置,用电加热水箱模拟热源对该装置进行了实验测试.实验结果表明,由于在本蒸馏系统中采用了多项降膜蒸发及降膜凝结技术,使其中大部分的蒸汽潜热及部分盐水的显热得到了多次重复利用,因而装置有较高的产水率.在供热水温度为75℃、系统内部压力为15kPa时,产水率达到110kg/h。对影响产水率的主要因素作了探索与分析,给出了合理的取值范围.     

铈基复合氧化物中晶格氧用于甲烷部分氧化制合成气

采用共沉淀法制备了Ce-M-O氧载体（M＝Fe、Mn、Cu）,并进行了XRD表征。研究了Ce-M-O中晶格氧部分氧化甲烷制合成气的反应。考察了再生时间、再生温度对氧载体部分氧化甲烷性能的影响。研究结果表明, Ce-Fe-O固溶体中的晶格氧适于部分氧化甲烷制合成气。在新鲜的Ce Fe O氧载体上存在少量的强氧化物种,导致开始阶段大部分甲烷被完全氧化,然后该氧载体能均匀地释放出具有高选择性的体相晶格氧将甲烷氧化为CO和H2。通过对氧载体再生条件的控制,可以有效提高目标产物的选择性,当再生温度为850℃,再生时间为7min时, 获得了最大的CO（96.68%）和H2（97.56%）选择性,同时H2与CO摩尔比达到2.02。在无气相氧存在下,用Ce-Fe-O中晶格氧实现甲烷部分氧化制合成气的方法是可行的。     

Methane Combustion over Pd/Al2O3 Catalyst: Effects of Chlorine Ions and Water on Catalytic Activity

The influences of residual chlorine ions and water on the performance of a Pd/Al₂O₃ catalyst in methane combustion have been studied. The results show that the catalyst containing Cl⁻ exhibits a relatively low activity, and the addition of water to the reaction system accelerates the deactivation process. The catalyst has been characterized by N₂ adsorption, X-ray fluorescence, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetry (TG). The results show that the presence of Cl⁻ appears to strongly inhibit the total oxidation of methane and hinder the dispersion of Pd on Al₂O₃. The formation of Pd(OH)₂ during the reaction is the most likely reason for the inhibition effect of water, which is confirmed by FT-IR and TG analysis. The regeneration of the Pd/Al₂O₃ catalyst can be achieved by purging in nitrogen at 550 °C.     

铁掺杂纳米ZnO室温脱硫剂的硫化及再生研究

为降低纳米ZnO脱硫剂的应用成本及避免对环境产生二次污染,本文对均匀沉淀法制备的铁掺杂纳米ZnO脱硫剂(FZ5.0)进行了硫化和再生循环试验研究,并利用XRD、XPS和TEM等表征手段对FZ5.0的硫化及再生前后的结构进行了分析。结果表明,脱硫剂表面存在3种脱硫产物,HS、S形成的吸附配合物和ZnS,370 ℃时可直接通入空气进行连续5次再生。经过第1次再生后纳米脱硫剂结构便趋于稳定,并在后面的循环过程中表现出较稳定的脱硫活性,但与新鲜脱硫剂相比较,其脱硫活性是新鲜脱硫剂的50%左右。再生过程中主要产物为SO₂气体,还有少量的硫酸盐生成,再生后样品的晶粒尺寸、形貌变化不大,但比表面积和孔容变化明显,这也是导致脱硫活性下降的主要原因。     

Surface Modification of Gold by Quercetin Monolayer for the Electrochemical Determination of Copper(II)

A quercetin monolayer has been prepared on top of the self‐assembled 3‐mercaptopropionic acid (MPA) layer for the copper ion determination. Cu²⁺ ions are readily accumulated on this modified electrode through the complex formation and electrochemically detected. With a quercetin layer, the redox process of Cu²⁺ became more reversible than at the MPA‐modified electrode. Complexation sites in MPA and quercetin were occupied within five min when the electrode was immersed in 10 μM Cu²⁺ solution. The MPA and quercetin layers were stable enough to allow repeated EDTA treatment to remove adsorbed Cu²⁺ for the surface regeneration. Only 7% decrease was found after ten times regeneration and use. Linear current response was found over the concentration range of 1 nM and 10 μM with detection limit of 0.1 nM. Common interfering ions such as Cd²⁺, Zn²⁺, and Fe^2+/3+ did not show any electrochemical response in the potential range of Cu²⁺ determination.     

Nanofibrous poly(lactic acid)/hydroxyapatite composite scaffolds for guided tissue regeneration

The production of nanofibrous PLA/HA composite scaffolds is described. The morphological, mechanical, surface, and thermal properties of the composites were extensively investigated. The results show that the mixture of PLA and HA formed smooth nanofibers without lumps. The incorporation of HA increased the mechanical strength of the nanofibers and changed the morphology, increasing the mean fiber diameter and pore size. Surface and internal properties confirmed that HA was homogeneously distributed inside the nanofibers and oriented towards their surface. The nanofiber composites allowed the adhesion and proliferation of pre-osteoblasts for up to 3 weeks.     

Fabrication and Characterization of an Electro-Compacted Collagen/Elastin/Hyaluronic Acid Sheet as a Potential Skin Scaffold

The development of biomimetic structures with integrated extracellular matrix (ECM) components represents a promising approach to biomaterial fabrication. Here, an artificial ECM, comprising the structural protein collagen I and elastin (ELN), as well as the glycosaminoglycan hyaluronan (HA), is reported. Specifically, collagen and ELN are electrochemically aligned to mimic the compositional characteristics of the dermal matrix. HA is incorporated into the electro-compacted collagen-ELN matrices via adsorption and chemical immobilization, to give a final composition of collagen/ELN/HA of 7:2:1. This produces a final collagen/ELN/hyaluronic acid scaffold (CEH) that recapitulates the compositional feature of the native skin ECM. This study analyzes the effect of CEH composition on the cultivation of human dermal fibroblast cells (HDFs) and immortalized human keratinocytes (HaCaTs). It is shown that the CEH scaffold supports dermal regeneration by promoting HDFs proliferation, ECM deposition, and differentiation into myofibroblasts. The CEH scaffolds are also shown to support epidermis growth by supporting HaCaTs proliferation, differentiation, and stratification. A double-layered epidermal-dermal structure is constructed on the CEH scaffold, further demonstrating its ability in supporting skin cell function and skin regeneration.