sodium borohydride

  • 文章类型: Journal Article
    随着胶合板在家具和室内装饰行业的应用越来越广泛,全球胶合板的产量不断增加。一个紧迫的问题是如何减少胶合板释放的甲醛,考虑到它对人类的致癌作用和对环境的危害。降低制备过程中使用的脲甲醛(UF)粘合剂的游离甲醛含量被认为是一种有效的方法。因此,有必要确定一种新型的甲醛清除剂。这里,强还原物质硼氢化钠用于还原和降解UF粘合剂中的游离甲醛,研究了其对UF胶粘剂和胶合板性能的影响。当将0.7%的硼氢化钠添加到甲醛与尿素的摩尔比为1.4:1的UF粘合剂中时,UF树脂的游离甲醛含量下降到0.21%,比未经处理的对照低53%。此外,从胶合板释放的甲醛减少到0.81毫克/升,比来自该组的降低~45%。处理后试样的结合强度可达~1.1MPa,与对照组相比,仅减少了约4%。这项通过还原法去除UF粘合剂中甲醛的研究可以为抑制最终产品中甲醛的释放提供一种新的方法。
    The global production of plywood is constantly increasing as its application in the furniture and interior decoration industry becomes more widespread. An urgent issue is how to decrease the formaldehyde released from plywood, considering its carcinogenic effect on humans and harm to the environment. Reducing the free formaldehyde content of the urea formaldehyde (UF) adhesives used in the preparation process is considered an effective method. Therefore, it is necessary to identify a new type of formaldehyde scavengers. Here, the strongly reducing substance sodium borohydride was used to reduce and degrade the free formaldehyde in UF adhesives, and its effects on the properties of the UF adhesive and plywood were studied. When 0.7% sodium borohydride was added to the UF adhesive with a molar ratio of formaldehyde to urea of 1.4:1, the free formaldehyde content of the UF resin decreased to 0.21%, which is 53% lower than that of the untreated control. Moreover, the formaldehyde released from the plywood was reduced to 0.81 mg/L, ~45% lower than that from the group. The bonding strength of the treated samples could reach ~1.1 MPa, which was only reduced by ~4% compared to that of the control. This study of removing formaldehyde from UF adhesive by reduction could provide a new approach for suppressing formaldehyde release from the final products.
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  • 文章类型: Journal Article
    硼氢化钠(NaBH4)已被公认为有前途的氢载体,归因于其卓越的储氢能力,拥有10.8重量%的高理论存储容量。尽管如此,利用传统的热解和水解方法仍然提出了一个巨大的挑战,以实现控制的氢气产生,特别是在环境条件下。在这项工作中,我们报告了一种创新的电化学策略,用于通过耦合NaBH4电氧化反应(BOR)在碱性介质中的阳极与析氢反应(HER)在酸性介质中的阴极生产H2。为了实现这一点,我们开发了一种双功能电催化剂,称为Pd-Mo2C@CNT,其中Pd纳米颗粒在嵌入N掺杂碳纳米管内的Mo2C上原位生长。该电催化剂在催化碱性BOR和酸性HER方面表现出优异的性能。我们开发了一种混合酸/碱电池,利用Pd/Mo2C@CNT作为阳极和阴极电催化剂。这种配置展示了非凡的自我维持能力,精确,即使在100mAcm-2的高电流密度下,法拉第效率也接近100%,并且不间断地间接释放存储在NaBH4中的H2。此外,这种电化学装置显示出作为燃料电池的巨大前景,具有提供20mWcm-2的最大功率密度的能力。
    Sodium borohydride (NaBH4 ) has earned recognition as a promising hydrogen carrier, attributed to its exceptional hydrogen storage capacity, boasting a high theoretical storage capacity of 10.8 wt %. Nonetheless, the utilization of traditional pyrolysis and hydrolysis methods still presents a formidable challenge in achieving controlled hydrogen generation especially under ambient conditions. In this work, we report an innovative electrochemical strategy for production H2 by coupling NaBH4 electrooxidation reaction (BOR) at anode in alkaline media with hydrogen evolution reaction (HER) at cathode in acidic media. To implement this, we have developed a bifunctional electrocatalyst denoted as Pd-Mo2 C@CNTs, wherein Pd nanoparticles are grown in situ on Mo2 C embedded within N-doped carbon nanotubes. This electrocatalyst demonstrates exceptional performance in catalyzing both alkaline BOR and acidic HER. We have developed a hybrid acid/alkali cell, utilizing Pd/Mo2 C@CNTs as the anode and cathode electrocatalysts. This configuration showcases remarkable capabilities for self-sustained, precise, and uninterrupted indirect release of H2 stored in NaBH4 , even at high current densities of 100 mA cm-2 with a Faraday efficiency approaching 100 %. Additionally, this electrochemical device exhibits significant promise as a fuel cell, with the ability to deliver a maximum power density of 20 mW cm-2 .
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  • 文章类型: Journal Article
    构建用于通过硼氢化钠的水解析氢的可靠且稳健的钴基催化剂是有吸引力的,但由于由金属浸出和金属钴的再氧化引起的失活而具有挑战性。通过Co-MOF的热解制备了独特的核壳结构冠状病毒样Co@C微球。这种特殊的Co@C具有微孔碳涂层以保持钴的还原状态并抵抗金属浸出。此外,在表面上离散生长的几个纳米凸块提供了富集的活性中心。应用于NaBH4的热解,Co@C-650,在650°C碳化,表现出最佳的活性和可靠的可回收性。这种可比较的性能归因于增加的金属活性位点和稳健的稳定性。
    Constructing a reliable and robust cobalt-based catalyst for hydrogen evolution via hydrolysis of sodium borohydride is appealing but challenging due to the deactivation caused by the metal leaching and re-oxidization of metallic cobalt. A unique core-shell-structured coronavirus-like Co@C microsphere was prepared via pyrolysis of Co-MOF. This special Co@C had a microporous carbon coating to retain the reduced state of cobalt and resist the metal leaching. Furthermore, several nano-bumps grown discretely on the surface afforded enriched active centers. Applied in the pyrolysis of NaBH4, the Co@C-650, carbonized at 650 °C, exhibited the best activity and reliable recyclability. This comparable performance is ascribed to the increased metallic active sites and robust stability.
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  • 文章类型: Journal Article
    As a promising hydrogen storage material, sodium borohydride (NaBH4) exhibits superior stability in alkaline solutions and delivers 10.8 wt.% theoretical hydrogen storage capacity. Nevertheless, its hydrolysis reaction at room temperature must be activated and accelerated by adding an effective catalyst. In this study, we synthesize Co nanoparticles supported on bagasse-derived porous carbon (Co@xPC) for catalytic hydrolytic dehydrogenation of NaBH4. According to the experimental results, Co nanoparticles with uniform particle size and high dispersion are successfully supported on porous carbon to achieve a Co@150PC catalyst. It exhibits particularly high activity of hydrogen generation with the optimal hydrogen production rate of 11086.4 mLH2∙min-1∙gCo-1 and low activation energy (Ea) of 31.25 kJ mol-1. The calculation results based on density functional theory (DFT) indicate that the Co@xPC structure is conducive to the dissociation of [BH4]-, which effectively enhances the hydrolysis efficiency of NaBH4. Moreover, Co@150PC presents an excellent durability, retaining 72.0% of the initial catalyst activity after 15 cycling tests. Moreover, we also explored the degradation mechanism of catalyst performance.
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  • 文章类型: Journal Article
    设计和构建具有高性能和低成本特性的过渡金属催化剂对于液氢存储材料势在必行。在这项研究中,我们使用硼氢化钠(NaBH4)水解的离子液体/水界面策略制备了超薄碳稳定的共掺杂CoxOy纳米薄膜(C-Co/CoxOyNFs)。由于其二维(2D)NF结构和复合碳的保护作用,C-Co/CoxOyNF催化剂对NaBH4水解产氢表现出显著的活性和耐久性。氢气生成速率达到8055mL·min-1·gCo-1(5106mL·min-1·gCat-1),催化剂可循环20次以上,在可比条件下超过大多数报道的金属基催化剂。此外,卓越的2DCo基NF结构,有许多活跃的网站,协助激活NaBH4和水分子,促进氢气生产。因此,这些结果提供了对NaBH4水解产生氢气的深入理解,以及合理设计高活性和耐用的2DNF催化剂的有效策略。
    The design and construction of transition metal catalysts with high performance and low-cost characteristics are imperative for liquid hydrogen storage materials. In this study, we prepared ultrathin carbon-stabilized Co-doped CoxOy nanofilms (C-Co/CoxOy NFs) using an ionic liquid/water interface strategy for sodium borohydride (NaBH4) hydrolysis. Owing to its two-dimensional (2D) NF structure and the protective effects of the composite carbon, the C-Co/CoxOy NF catalyst exhibited remarkable activity and durability for hydrogen generation from NaBH4 hydrolysis. The hydrogen generation rate reached 8055 mL·min-1·gCo-1 (5106 mL·min-1·gCat-1) and the catalyst could be recycled more than 20 times, surpassing most reported metal-based catalysts under comparable conditions. In addition, the exceptional 2D Co-based NF structures, with numerous active sites, assisted in the activation of NaBH4 and water molecules, promoting hydrogen production. Thus, these results provided an in-depth understanding of hydrogen generation from NaBH4 hydrolysis, and an effective strategy for rationally designing highly active and durable 2D NF catalysts.
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  • 文章类型: Journal Article
    先前的研究表明,褐藻多糖具有抗病毒活性。我们假设来自海洋植物的天然多糖可能对抗SARS-CoV-2活性有影响。利用多糖文库通过高通量筛选靶向3CLpro酶,我们发现来自海藻Eckloniakurome的粗多糖375阻断了3CLpro酶活性,并在细胞中显示出良好的抗SARS-CoV-2感染活性。Further,我们显示来自375的均质多糖37502可能与3CLpro良好结合并干扰刺突蛋白与ACE2受体的结合。结构表征揭示37502是藻酸盐。这些结果表明,375对SARS-CoV-2的生物活性可能靶向涉及病毒感染和复制的多个关键分子。以上结果表明375可能是抗SARS-CoV-2的潜在候选药物。
    Previous researches suggested that polysaccharides from brown algae had anti-virus activity. We hypothesized that nature polysaccharide from marine plants might have the effect on anti-SARS-CoV-2 activity. By high throughput screening to target 3CLpro enzyme using polysaccharides library, we discover a crude polysaccharide 375 from seaweed Ecklonia kurome blocked 3CLpro enzymatic activity and shows good anti-SARS-CoV-2 infection activity in cell. Further, we show that homogeneous polysaccharide 37502 from the 375 may bind to 3CLpro well and disturb spike protein binding to ACE2 receptor. The structure characterization uncovers that 37502 is alginate. These results imply that the bioactivities of 375 on SARS-CoV-2 may target multiple key molecules implicated in the virus infection and replication. The above results suggest that 375 may be a potential drug candidate against SARS-CoV-2.
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  • 文章类型: Journal Article
    银纳米粒子(AgNPs)具有稳定的反应性和优异的光吸收性能。它们可以应用于各种行业,如环境保护,生化工程,和分析物监测。然而,合成AgNPs和确定它们作为着色物质的适当剂量是困难的任务。在这项研究中,优化AgNP的合成工艺,获得一种简单的环境中痕量汞的检测方法,我们评估了几个因素,包括试剂添加顺序,反应温度,反应时间,溶液的pH值,和试剂浓度-考虑AgNPs的颜色强度和纯度作为反应优化标准。合成AgNP的最佳工艺如下:将10mM硝酸银与柠檬酸三钠在热水浴中混合10分钟;然后,添加10mM硼氢化钠以产生AgNPs,并保持搅拌2小时;最后,调节pH至12以获得最稳定的产品。对于基于AgNP的汞检测,在0.1-2ppb的浓度范围内,汞的校准曲线表现出良好的线性(R2>0.99)。这项研究提供了一种稳定且出色的AgNP合成技术,可以改善涉及AgNP介导的反应的各种应用,并且有可能被开发为使用昂贵的检测设备的替代方法,并应用于食品中汞的检测。
    Silver nanoparticles (AgNPs) have stable reactivity and excellent optical absorption properties. They can be applied in various industries, such as environmental protection, biochemical engineering, and analyte monitoring. However, synthesizing AgNPs and determining their appropriate dosage as a coloring substance are difficult tasks. In this study, to optimize the process of AgNP synthesis and obtain a simple detection method for trace mercury in the environment, we evaluate several factors-including the reagent addition sequence, reaction temperature, reaction time, the pH of the solution, and reagent concentration-considering the color intensity and purity of AgNPs as the reaction optimization criteria. The optimal process for AgNP synthesis is as follows: Mix 10 mM of silver nitrate with trisodium citrate in a hot water bath for 10 min; then, add 10 mM of sodium borohydride to produce the AgNPs and keep stirring for 2 h; finally, adjust the pH to 12 to obtain the most stable products. For AgNP-based mercury detection, the calibration curve of mercury over the concentration range of 0.1-2 ppb exhibits good linearity (R2 > 0.99). This study provides a stable and excellent AgNP synthesis technique that can improve various applications involving AgNP-mediated reactions and has the potential to be developed as an alternative to using expensive detection equipment and to be applied for the detection of mercury in food.
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  • 文章类型: Journal Article
    Mechanochemistry has been proved to be an effective method to remediation of organic-contaminated sites. However, the high ball-to-powder mass ratio (CR) limits the large-scale application of mechanochemistry. In this study, co-milling additives were introduced to enhance the mechanochemical degradation of decabromodiphenyl ether (BDE209)-contaminated soil under the condition of low CR. Based on additive screening experiments, sodium borohydride was selected as the ideal additive to assist the mechanochemical degradation of BDE209, and the resulting removal efficiency was approximately 100% with 2 h of ball milling at a rotational speed of 550 rpm. The main degradation intermediates and degradation pathway of BDE209 were identified using gas chromatography-tandem mass spectrometry. It was proposed that the degradation of BDE209 by sodium borohydride-assisted mechanochemistry was a concurrent process of stepwise and multistage debromination. Meanwhile, the meta-bromine atom in BDE209 was more susceptible to debromination than those at the para and ortho positions. The evolution of the concentration of Br- was monitored by ion chromatography, which revealed that reduction and oxidation both occurred in the removal of BDE209. This paper provides a new perspective for reducing the CR in the mechanochemical remediation of BDE209-contaminated soil.
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  • 文章类型: Journal Article
    Catalytic hydrogen reduction has appeared as a promising strategy for chemical denitrification with advantages of high activity and simple operation. However, the risk and low utilization of H2 is the disadvantage of catalytic hydrogen reduction. In recent years, catalytic reduction reactions in the presence of sodium borohydride (NaBH4) have been extensively studied. NaBH4 can be used as an electron source to generate electrons on the surface of the catalyst and can catalyze the reduction of pollutants. But it makes commercialization costly and causes significant environmental pollution if widely use NaBH4. In this study, we prepared supported Pd/Sn bimetallic nanoparticles which could adsorb NaBH4 during the preparation of the Pd/Sn bimetallic catalyst as the prestoring reductant. No additional reducing agent is required during nitrate reduction process. The performance and mechanism for nitrate reduction by using Pd/Sn bimetallic nanoparticles were discussed. Moreover, the catalyst D-Pd1/Sn1 reached a complete nitrate removal in the municipal wastewater treatment plant effluent water within 3 h. The results provide a prospect for denitrification in biological wastewater treatment plants.
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  • 文章类型: Journal Article
    Catalytic hydrogen reduction appears to be a promising strategy for nitrate removal. However, the danger and low utilization of H2 are the disadvantages of catalytic hydrogen reduction. Sodium borohydride (NaBH4), considered a potential candidate for hydrogen storage, has been investigated as an electron source for the catalytic reduction of contaminants. However, extensive use of NaBH4 makes commercialization costly and causes environmental pollution. In this study, we prepared supported Cu/Pd bimetallic nanoparticles that could prestore hydrogen. No additional reducing agent was required during the nitrate reduction process. The performance and mechanism of Cu/Pd bimetallic nanoparticles for nitrate reduction are discussed. Good performance was obtained with high reactivity (99.04% nitrate removal efficiency) and high selectivity for N2 (94.71%). The Cu/Pd bimetallic catalyst could be recovered by NaBH4 for 5 cycles. Moreover, a 97.49% nitrate removal efficiency was obtained for actual wastewater, indicating good prospects for nitrate reduction applications.
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