The authors gratefully acknowledge financial support from the Belgian Federal government (Belspo through the IAP VI/27 and IAP-7/05 programs), the European Union's Seventh Framework Programme (FP7/2007-2013 under grant agreement no. 310651 SACS), the Flemish government in the form of long-term structural funding "Methusalem" grant METH/08/04 CASAS, the "Strategisch Initiatief Materialen" SoPPoM program, and the Fund for Scientific Research Flanders (FWO) grant G.0349.12. W.B. gratefully acknowledge the chemistry department of the KU Leuven for a FLOF-scholarship. The authors thank UOP Antwerp for the kind donation of zeolite samples and the mechanical workshop of the KU Leuven for helping with the design and construction of the heating/vacuum cell used in this study.

注意事项:本报告中所使用的化学品和试剂采用相应的安全保护措施（实验服，手套，护目镜，通风柜）谨慎处理。本研究使用的微孔无机材料（具有尺寸范围从1至5微米的沸石），因此特殊的注意力引导到使用适当的灰尘保护（防尘口罩）的操作涉及。我们建议采用适当操作和/或废物处置前，在这项工作中所使用的化学品和试剂的相关材料安全数据（MSDS）的咨询。 1.沸石前处理<ol><li>热预处理 注意:使用除去杂质，如有机杂质之前，预先处理沸石材料，这可能会阻碍银簇的形成和发光。 <ol><li>称取克工业LTA（Na）的沸石（LTA商业沸石含有钠作为其框架抗衡离子）与帝宝坐在均匀它瓷托盘。 </li><li>使用的具有1小时的间隔5℃/分钟的温度变化速率在80℃和110℃，以避免沸石结构破坏在450℃下过夜加热沸石粉末在马弗炉。 </li><li>从烘箱中取出的沸石材料，让它冷却到室温环境条件下。 </li></ol></li><li>沸石颗粒的尺寸选择 注意:这将产生的起始沸石材料的更均匀的粒度分布，创造必要的均匀的薄膜。这一步也消除大量无定形颗粒，这往往是存在于工业生产的沸石。 <ol><li>称取g市售的LTA（Na）的，并将其悬浮到1升的去离子水。 </li><li>超声处理该悬浮液1小时，剧烈摇动该悬浮液用手工每隔10分钟。 </li><li>倒入悬浮液成液塑筒（1L）30分钟。颗粒小于10微米的尺寸留在悬浮液中，但较大的颗粒沉淀。 </li><li>倒出该悬浮液，并使用布氏漏斗通过过滤回收该粉末。用去离子水洗涤回收的粉三次。 </li><li>如在步骤1.1.2中所述的热治疗的粉末。 </li></ol></li></ol> 2.发光LTA（娜） - 银沸石复合材料的制备<ol><li>发光性银的合成交换LTA沸石[LTA（钠）-Ag]作为参考材料<ol><li>溶解在200毫升中的250毫升的高密度聚丙烯（HDPE）瓶的去离子水74.8毫克硝酸银。 </li><li>称重1克预处理LTA（Na）的样品，并在硝酸银溶液挂起。 </li><li>离开的HDPE瓶中搅拌过夜到室温的最终过端摇床烘箱。 </li><li>过滤用布氏漏斗的悬浮液并用去离子水洗涤沸石粉末3次。 </li><li>热回收的粉末在45马弗炉0℃下，使用如在步骤1.1.2中描述的相同的过程。 </li><li>冷却样品，并放置在具有受控湿度（98％相对湿度）的干燥器。通过将干燥器内的饱和硫酸钾溶液控制相对湿度15 </li><li>使用荧光分光光度计以及其外部量子效率测量样品的激发和发射光谱（在不同的波长）。 <ol><li>通过将样品在1毫米路径石英比色皿测量二维激发发光图。收集开始上述激发波长可达使用5纳米的步骤和0.1秒的驻留时间800纳米30纳米的发射光谱。 </li><li>申请使用用于灯强度和波长相关的检测的发射路径的原始数据的仪器软件校正。此外，使用长通滤波器，以避免在两维曲线二阶峰。 </li><li>执行量子efficiency测量通过使用附连到分光光度计的积分球16记录的发射扫描从240纳米到两种沸石样品和硫酸钡600纳米使用4-参考260nm处作为激发波长，然后计算使用仪器的软件的量子效率。 </li></ol></li></ol></li></ol> 3.发光[LTA（李） - 银]沸石复合材料的制备<ol><li>部分交换锂LTA沸石的合成LTA（李） 注:遵循的程序部分交换LTA（李）沸石由Yahiro和合作者报告被改编的制造17。 <ol><li>溶解在2.5L去离子水中17.2克硝酸锂。 </li><li>倾0.5升的硝酸锂溶液加入到1升的HDPE瓶中。 </li><li>称重3G-预处理LTA（Na）的沸石，然后在包含硝酸锂溶液中的高密度聚乙烯瓶中挂起。 </li><li>使用结束-O搅动烧瓶在室温下过夜VER-端摇床烘箱。 </li><li>过滤用布氏漏斗的悬浮液并用去离子水洗涤所回收的粉末3次。 </li><li>执行锂交换<ol><li>加0.5升的新鲜硝酸锂溶液（3.1.1），以含有从过滤步骤（3.1.5）将回收的粉末的1升的HDPE瓶中。 </li><li>重复步骤3.1.4和3.1.5。 </li><li>重复步骤3.1.6.1和3.1.6.2另外4倍。 </li></ol></li><li>回收的沸石粉末，并使用与1小时的间隔5℃/分钟的温度变化速率在80℃和110℃下过夜它加热在450℃的马弗炉。 </li></ol></li><li>发光的合成LTA（李） - 银]沸石<ol><li>溶解在200毫升用250毫升的HDPE瓶的去离子水74.8毫克硝酸银。 </li><li>权衡部分交换锂的LTA沸石[LTA（李）〕1克，并在硝酸银溶液（3.2.1）挂起。 </li><li>搅动HDPE FL问使用在室温下的最终过端摇床烘箱中过夜。 </li><li>过滤用布氏漏斗的悬浮液并用去离子水洗涤回收的沸石粉末3次。 </li><li>在马弗炉中在450℃下使用的用1小时的时间间隔5℃/分钟的温度变化速率在80℃和110℃下过夜加热处理的粉末。 </li><li>使用含有内（98％相对湿度）的饱和硫酸钾溶液在干燥器受控湿度条件下冷却样品。15 </li><li>测量以下步骤2.1.7中描述的方法的样品的激发和发射光谱，以及其外部量子效率。 </li><li>进行热重分析（TGA）来确定在不同温度下的样品中的水含量。1简言之，将30至50mg的所制备样品的在铂样品支架和它装入TGA设备中。测量从50重量损失℃，直至600℃用氮气流（90毫升/分钟）下以5℃/分钟的加热速率。 </li></ol></li></ol> 4.制作一个LTA（李） - 银/聚乙烯亚胺（PEI）复合镀膜的湿度传感应用注:本报告中使用的沉积过程进行了修改，并从18参考改编。 <ol><li> LTA（李） - 银胶体悬浮液的准备。 <ol><li>稀释1ml所商用50重量％PEI溶液至100毫升的去离子水。 </li><li>称取250毫克发光LTA（李） - 银材料。 </li><li>混合沸石和PEI解决方案一起125毫升的HDPE瓶并剧烈摇晃暂停。 </li><li>放置在一个40千赫超声波仪浴中的瓶中于室温下过夜，以获得均匀的悬浮液。 </li><li>倒入LTA（李） - 银/ PEI悬挂成一个喷雾瓶。 </li></ol></li><li>一个LTA（李） - 银/ PEI薄膜沉积到传感器PROT石英板otype生产。 <ol><li>通过用离子交换水和丙酮漂洗它连续，膜沉积之前清洁的石英板。干燥烘箱中的清洁板，在80℃1小时。 </li><li>喷雾涂布在石英板的一侧，通过从约20厘米的距离水平地放置在石英板在铝箔的一个清洁片和喷涂三次（3秒每时间）。放置一个干燥箱内的涂覆板在50℃下30分钟。 </li><li>重复步骤4.2.2另外4次直到薄膜是均匀的。 </li></ol></li><li>水化/脱水传感器原型。 <ol><li>放置石英涂层板进入一个内部的加热/真空室的样品室。5 </li><li>通过在涂板的顶部放置一个清洁石英板中结合有橡胶环关闭细胞的样品室和密封使用特氟隆塞和螺钉的小区， 如图2中所描绘。 </li><li>应用高真空，我们为了ING低于10 -3毫巴的压力，向细胞过夜以脱水样品。 </li><li>通过使用紫外灯在视觉上监视沉积膜的发射颜色的变化（在可见光区）。 </li><li>打开样品室来监测的发光颜色的变化，在可见光区域，在使用时的UV灯膜的补液。 </li><li>从步骤4.3.2开始周期多次重复4.3.5测试LTA（李） - 银/ PEI薄膜的可逆性。 </li></ol></li></ol>

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The authors have nothing to disclose.

A simple device to demonstrate the proof of concept of using LTA(Li)-Ag as a luminescence based humidity sensor was produced by spray coating the LTA(Li)-Ag powder suspended in a PEI solution onto a quartz plate. The PEI solution produces a polymer layer with homogenous thickness when the water is evaporated. The polymer-zeolite composite layer displays similar luminescent properties as that of the zeolite in powder form. The PEI/LTA(Li)-Ag zeolite composite displays the expected water-responsive luminescent properties, whose emission color changes upon variations in the water content present in the composite at relatively low humidity scale. 
Replacing Na with Li ions in LTA zeolites (calculated exchange rate 33%) has a notable impact on the self-assembly and stabilization of luminescent silver clusters in the LTA(Li) scaffolds leading to unique optical properties. The EQE of LTA(Li)-Ag as compared to LTA(Na)-Ag samples is enhanced by more than one order of magnitude. Moreover, the emission colors displayed by the LTA(Li)-Ag samples have a water-dependence, providing a potential application of the samples as luminescence based humidity sensors. 
We have thus demonstrated an easy method to fabricate a luminescent film-like humidity sensor through which changes in hydration levels can be visually monitored simply by using a UV lamp. The availability of the raw materials, the direct visualization of the color changes correlated with humidity content, the photo-stability of the films, and the relative ease of fabricating cost-effective devices make these luminescent materials potential candidates to compete with state-of-the-art humidity sensors based upon electrical responses. The procedure described in this report could also be applied and extended to different substrates, at different micro and macro scales, to make the sensor more flexible. Additionally, several critical steps during the fabrication of Ag-zeolites, which play an important role in determining the final optical properties of such materials, were discussed in this protocol. For instance, the pre-cleaning of the raw zeolite material leads to the removal of optical and chemical impurities, as well as to homogenous zeolite crystal size distribution. This is crucial for the incorporation of zeolites into functional devices. One limitation of the present methodology is the restriction on the use of thin film sensors beyond 75 &#176;C. This is mainly due to the decomposition of the PEI polymer, rather than to the degradation of the LTA(Li)-Ag zeolites, which can withstand up to 500 &#176;C. The use of heat-resistant polymers, such as polyvinyl alcohol, could expand the temperature range up to 200 &#176;C. We expect that further investigations will be directed to the development of methodologies for the synthesis of nanostructured Ag-zeolite composites with (multi)functional properties and finally to the design of advanced sensor prototypes.

通过自组装在密闭沸石基质形成小亚纳米oligoatomic银团簇显示独特的光学性质。1-5这种银沸石复合材料具有高的化学和光学稳定性。然而，它们的光致发光特性是高度依赖于银簇的局部环境。在银 - 沸石复合影响光学特性的环境条件，可分为内在和外在属性。内在特性都涉及到沸石拓扑，抗衡离子的类型和银负载1。另一方面，外在属性关联到合成后的变化，如吸附或水分子的存在沸石空腔。3,4-后者属性赋予对银-沸石复合，以光学地对外部刺激，例如在沸石骨架6-8内的水分的变化作出反应的能力</suP&gt;或确定气体的存在;因此它们的水蒸气和气体传感器的使用已被建议。9,10- 在最近的研究中，我们已经表明，银-沸石的湿气光学响应不仅相关，在其发射的吸收或骤冷的变化，但也对不同的发射颜色外观相对于它们的含水量。5的稳定化在部分锂交换的LTA沸石分别导致其改变在相对低湿度的比例反映在从蓝色动态颜色变化至绿色/黄色发射脱水和水合样品在透湿响应材料的形成中，银金属簇的。因此，使用这些材料作为基于发光的湿度传感器中提出的。迄今为止，不同类型的材料，如电解质，陶瓷，聚合物和纳米复合材料已经提出了用于在湿度b监控的变化ASED上电和光反应。11,12在此详细协议中，我们的目标是展示一个证明的概念为LTA（李）-Ag沸石的应用湿度传感器和用于进一步原型发展。由于LTA（李）-Ag沸石的通用性被纳入不同的衬底，其潜在的可扩展性和成本效益的制造，原型设计可能来促进。13这样的传感器可以具有在不同的工业部门，例如在潜在适用性农业，以及汽车和造纸工业。14

<table><tbody><tr><td>LTA(Na) zeolite</td><td>UOP</td><td>Molsiv adsorbent 4A</td><td></td></tr><tr><td>Silver nitrate</td><td>Sigma Aldrich</td><td>209139</td><td>&amp;ge;99.0%</td></tr><tr><td>Lithium nitrate</td><td>Sigma Aldrich</td><td>62574</td><td>&amp;ge;99.0%, calc. on dry substances</td></tr><tr><td>Polyethyleneimine solution</td><td>Sigma Aldrich</td><td>3880</td><td>~50% H&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>Scanning electron microscope (SEM)</td><td>JEOL</td><td>JSM-6010LV</td><td></td></tr><tr><td>Thermogravimetric analyzer</td><td>TA instruments</td><td>Q500</td><td></td></tr><tr><td>Spectrofluorimeter</td><td>Edinburgh instruments</td><td>FLS980-s</td><td></td></tr><tr><td>Integrating sphere</td><td>Labsphere</td><td>4P-GPS-033-SL</td><td></td></tr></tbody></table>

nanostructured ag-zeolite composites as luminescence-based humidity sensors

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film.

在LTA银沸石的SEM显微照片的阳离子交换和热处理步骤之后进行记录。随后，光致发光的二维（2D）激发了两种水合LTA（Na）的-Ag及LTA（李）-Ag沸石（ 图1）的测量/发射曲线。用XPS对银交换的沸石，以确定它们的化学成分进行元素分析。分析表明，在LTA（Na）的和LTA（锂）的沸石的银交换非常接近与分别19.6％（重量）和21.5％（重量），银的重量百分比。在重量百分比的差异可以归因于锂原子的低级原子量。此外，元素分析还表明，锂交换后的Na的33％被替换。在样品上进行的阳离子交换和随后的热处理步骤似乎不影响LTA晶体的结构中，通过扫描电镜所证明。此外，较大的银N形成沸石晶体的表面上anoparticles没有可视化。发光特性在很大程度上他们的水合状态都LTA（李） - 银和LTA（娜） - 银样品之间的差异。通过将锂进入沸石框架作为抗衡阳离子，在激发最大值蓝移为LTA（Na）的-Ag及LTA（李）-Ag，分别发生从370纳米至260纳米。与此相反的最大发射经历了从550到565纳米的加入李进系统一个红色的小转变。这些样品之间的最大区别在其外部量子效率（EQE）被观察到。 LTA（钠）-Ag沸石具有约4％的EQE在其激发最大值（370纳米），而EQE为LTA（李）-Ag沸石达到62％（当在260nm激发）。这将导致一个明亮的黄色发光粉在254纳米的紫外线照射。 陆路交通管理局（李） - 银样品的发光性能还取决于的含水量系统。这是通过TGA和温度依赖的荧光实验的组合示出，TGA相关温度至沸石的水合程度。此外，温度为间接相关，通过使用一个内部的加热单元（ 图2）由LTA（李）-Ag样品显示的发光颜色。从黄色发光的颜色变化绿蓝，从LTA除水时，（李） - 银系统。该EQE稳步上升，从62％（水合状态）下降到21％（脱水状态）。 因为LTA（李）-Ag的水响应行为的，使用这种材料由粉末悬浮成PEI溶液以制造基于发光湿度传感器原型，随后喷雾复合涂覆到石英板。图像（在日光和紫外光照射）的喷涂LTA（李）-Ag / PEI薄膜和SEM显微照片显示在图3中 ，我们观察到，通过USI<html>纳克得到此涂布步骤，在发光方面具有聚合物 - 沸石复合的相对同质层。的SEM显微照片表明，该沸石晶体不是由涂覆程序改变。通过使用一个内部的加热/真空室也有人证明，聚合物 - 沸石膜保留哪些是在粉末形式的沸石所观察到的水响应性的特性。 <img alt="图1" src="/files/ftp_upload/54674/54674fig1.jpg" /> 图1:SEM 照片和银色的发光性能交换LTA沸石 SEM照片和LTA（娜） -银（A，B）和LTA（李） -银（C，D）的二维激发-发射图。在2D激发发光地块插图下不同的激发波长（254，300，366和450纳米）显示样品的模拟发射颜色。<html> OAD / 54674 / 54674fig1large.jpg"目标="_空白"&gt;点击此处查看该图的放大版本。 <img alt="图2" src="/files/ftp_upload/54674/54674fig2.jpg" /> 图2:LTA（李） -银的发光性能水化水平的影响。 。 一 ）在本研究中B）TGA积为LTA（李）的LTA（李） -银样品C）归一化发射光谱（260时nm激发）所采用的内部加热/真空室的示意图-银样品在不同温度下测得的。D）计划显示实际样品相对于含水量的发光颜色的变化。 <a href="http://ecsource.jove.com/files/ftp_upload/54674/54674fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> ftp_upload / 54674 / 54674fig3.jpg"/&gt; 图3: 基于一个LTA（李） -银/ PEI复合发光湿度传感器。 a）根据日光照明的涂板的照片。 （B，C）根据254nm的UV光照射的脱水和水合涂板，分别四 ）示出LTA（Li的分布）的石英表面上-Ag结晶沉积膜的SEM显微照片的照片。插图显示原始SEM显微照片。e）该水合和脱水的PEI / LTA（李）-Ag沸石复合，排放最大值10水合期间/使用260nm的作为激发波长。˚F脱水周期）的选定区域的放大剧情显示PEI / LTA（李）10水合/脱水循环后-Ag分子筛复合的最大发射剖面的行为。 <a href="http://ecsource.jove.com/files/ftp_upload/54674/54674fig3large.jpg" target="_blank">请点击此处为vi</a>EW这个数字的放大版本。

Watch this Scientific Journal Video about Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors at JoVE.com

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

A protocol for the synthesis of moisture-responsive luminescent Ag-zeolite composites is described in this report.

纳米银沸石复合材料作为基于发光的湿度传感器

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high ...

nanostructured-ag-zeolite-composites-as-luminescence-based-humidity

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

10.1K 次观看.  KU Leuven. A protocol for the synthesis of moisture-responsive luminescent Ag-zeolite composites is described in this report.

视频: Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 &#181;m were made by templated electrodeposition within the pores of polycarbonate track-etched (PCTE) or anodized aluminum oxide (AAO) membranes, respectively. In the photocatalytic experiments, the ZnO and TiO2 phases acted as photoanodes, and Ag as cathode. No external circuit is needed to connect both electrodes, which is a key advantage over conventional photo-electrochemical cells. For making segmented Ag|ZnO nanowires, the Ag salt electrolyte was replaced after formation of the Ag segment to form a ZnO segment attached to the Ag segment. For making coaxial TiO2-Ag nanowires, a TiO2 gel was first formed by the electrochemically induced sol-gel method. Drying and thermal annealing of the as-formed TiO2 gel resulted in the formation of crystalline TiO2 nanotubes. A subsequent Ag electrodeposition step inside the TiO2 nanotubes resulted in formation of coaxial TiO2-Ag nanowires. Due to the combination of an n-type semiconductor (ZnO or TiO2) and a metal (Ag) within the same nanowire, a Schottky barrier was created at the interface between the phases. To demonstrate the photocatalytic activity of these nanowires, the Ag|ZnO nanowires were used in a photocatalytic experiment in which H2 gas was detected upon UV illumination of the nanowires dispersed in a methanol/water mixture. After 17 min&#160;of illumination, approximately 0.2 vol% H2 gas was detected from a suspension of ~0.1 g of Ag|ZnO nanowires in a 50 ml 80 vol% aqueous methanol solution.

Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

Procedures are outlined to prepare segmented and coaxial nanowires via templated electrodeposition in nanopores. As examples, segmented nanowires consisting of Ag and ZnO segments, and coaxial nanowires consisting of a TiO2 shell and a Ag core were made. The nanowires were used in photocatalytic hydrogen formation experiments.

制备和使用光催化活性分段银|氧化锌和二氧化钛同轴<sub&gt; 2</sub&gt;银纳米线制成由模板电

Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and ...

科研

工程学

Synthesis of Zeolites Using the ADOR (Assembly-Disassembly-Organization-Reassembly) Route

Zeolites are an important class of materials that have wide ranging applications such as heterogeneous catalysts and adsorbents which are dependent on their framework topology. For new applications or improvements to existing ones, new zeolites with novel pore systems are desirable. We demonstrate a method for the synthesis of novel zeolites using the ADOR route. ADOR is an acronym for Assembly, Disassembly, Organization and Reassembly. This synthetic route takes advantage of the assembly of a relatively poorly stable that which can be selectively disassembled into a layered material. The resulting layered intermediate can then be organized in different manners by careful chemical manipulation and then reassembled into zeolites with new topologies. By carefully controlling the organization step of the synthetic pathway, new zeolites with never before seen topologies are capable of being synthesized. The structures of these new zeolites are confirmed using powder X-ray diffraction and further characterized by nitrogen adsorption and scanning electron microscopy. This new synthetic pathway for zeolites demonstrates its capability to produce novel frameworks that have never been prepared by traditional zeolite synthesis techniques.

Synthesis of Zeolites Using the ADOR Assembly-Disassembly-Organization-Reassembly Route

A protocol for the preparation of novel zeolites by the ADOR (Assembly-Disassembly-Organization-Reassembly) synthetic route is presented.

沸石使用ADOR（汇编拆卸组织-重组）路线的合成

Zeolites are an important class of materials that have wide ranging applications such as heterogeneous catalysts and adsorbents which are dependent on ...

化学

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

检测和钯的回收，从城市矿山黄金和钴金属使用标有纳米货车车轮形的孔隙新型传感器/吸附剂

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (&#181;PAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

The study demonstrates the growth of iridium oxide-reduced graphene oxide (IrO2-RGO) nanohybrid thin films on irregular and rough screen-printed carbon substrate through a green electrochemical synthesis, and their implementation as a pH sensor with a patterned paper-fluidic platform.

氧化铱还原氧化石墨烯纳米杂化薄膜修饰丝网印刷电极一次性电化学微流控纸pH传感器

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use ...

Adsorption Device Based on a Langatate Crystal Microbalance for High Temperature High Pressure Gas Adsorption in Zeolite H-ZSM-5

We present a high-temperature and high-pressure gas adsorption measurement device based on a high-frequency oscillating microbalance (5 MHz langatate crystal microbalance, LCM) and its use for gas adsorption measurements in zeolite H-ZSM-5. Prior to the adsorption measurements, zeolite H-ZSM-5 crystals were synthesized on the gold electrode in the center of the LCM, without covering the connection points of the gold electrodes to the oscillator, by the steam-assisted crystallization (SAC) method, so that the zeolite crystals remain attached to the oscillating microbalance while keeping good electroconductivity of the LCM during the adsorption measurements. Compared to a conventional quartz crystal microbalance (QCM) which is limited to temperatures below 80 &#176;C, the LCM can realize the adsorption measurements in principle at temperatures as high as 200-300 &#176;C (i.e., at or close to the reaction temperature of the target application of one-stage DME synthesis from the synthesis gas), owing to the absence of crystalline-phase transitions up to its melting point (1,470 &#176;C). The system was applied to investigate the adsorption of CO2, H2O, methanol and dimethyl ether (DME), each in the gas phase, on zeolite H-ZSM-5 in the temperature and pressure range of 50-150 &#176;C and 0-18 bar, respectively. The results showed that the adsorption isotherms of these gases in H-ZSM-5 can be well fitted by Langmuir-type adsorption isotherms. Furthermore, the determined adsorption parameters, i.e., adsorption capacities, adsorption enthalpies, and adsorption entropies, compare well to literature data. In this work, the results for CO2 are shown as an example.

A protocol for high-temperature and high-pressure gas adsorption measurements on zeolite H-ZSM-5 using an adsorption measurement device based on a langatate crystal microbalance is presented. Prior to the adsorption measurements, the synthesis of zeolite H-ZSM-5 on the langatate crystal microbalance sensor by the steam-assisted crystallization (SAC) method is demonstrated.

基于一个Langatate体微天平的高温高压气体吸附在分子筛吸附器H-ZSM-5

We present a high-temperature and high-pressure gas adsorption measurement device based on a high-frequency oscillating microbalance (5 MHz langatate ...

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 and a superhydrophobic agent were coated on the HGM surface in one step. TBT and PFOTES were selected as the Ti source and the superhydrophobic agent, respectively. They were both coated on the HGM, and after the hydrothermal process, the TBT turned to anatase TiO2. In this way, a PFOTES/TiO2-coated HGM (MCHGM) was prepared. For comparison, PFOTES single-coated HGM (F-SCHGM) and TiO2 single-coated HGM (Ti-SCHGM) were synthesized as well. The PFOTES and TiO2 coatings on the HGM surface were demonstrated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive detector (EDS) characterizations. The MCHGM showed a higher contact angle (153&#176;) but a lower sliding angle (16&#176;) than F-SCHGM, with a contact angle of 141.2&#176; and a sliding angle of 67&#176;. In addition, both Ti-SCHGM and MCHGM displayed similar IR reflectivity values, which were about 5.8% higher than the original HGM and F-SCHGM. Also, the PFOTES coating barely changed the thermal conductivity. Therefore, F-SCHGM, with a thermal conductivity of 0.0479 W/(m&#183;K), was quite like the original HGM, which was 0.0475 W/(m&#183;K). MCHGM and Ti-SCHGM were also similar. Their thermal conductivity values were 0.0543 W/(m&#183;K) and 0.0543 W/(m&#183;K), respectively. The TiO2 coating slightly increased the thermal conductivity, but with the increase in reflectivity, the overall heat-insulation property was enhanced. Finally, since the IR-reflecting property is provided by the HGM coating, if the coating is fouled, the reflectivity decreases. Therefore, with the superhydrophobic coating, the surface is protected from fouling, and its lifetime is also prolonged.

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method

This manuscript proposes a soft-chemistry method to synthesize superhydrophobic, TiO2-coated hollow glass microspheres (HGM) with high IR-reflective properties.

二氧化钛<sub&gt; 2</sub与由软化学法合成的超疏水性和高IR反射属性&gt;涂覆的空心玻璃微球

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 ...

Aerosol-assisted Chemical Vapor Deposition of Metal Oxide Structures: Zinc Oxide Rods

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, their high cost production and/or incompatibility with microfabrication technologies, due to the use of pre-deposited catalyst-seeds and/or high processing temperatures exceeding 900 &#176;C, represent a drawback for a widespread use of these methods. Here, however, we report the synthesis of ZnO rods via a non-catalyzed vapor-solid mechanism enabled by using an aerosol-assisted chemical vapor deposition (CVD) method at 400 &#176;C with zinc chloride (ZnCl2) as the precursor and ethanol as the carrier solvent. This method provides both single-step formation of ZnO rods and the possibility of their direct integration with various substrate types, including silicon, silicon-based micromachined platforms, quartz, or high heat resistant polymers. This potentially facilitates the use of this method at a large-scale, due to its compatibility with state-of-the-art microfabrication processes for device manufacture. This report also describes the properties of these structures (e.g., morphology, crystalline phase, optical band gap, chemical composition, electrical resistance) and validates its gas sensing functionality towards carbon monoxide.

Columnar zinc oxide structures in the form of rods are synthesized via aerosol-assisted chemical vapor deposition without the use of pre-deposited catalyst-seed particles. This method is scalable and compatible with various substrates based on either silicon, quartz or polymers.

金属氧化物结构的气溶胶辅助化学气相沉积: 氧化锌棒

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, ...

Resource Recycling of Red Soil to Synthesize Fe2O3/FAU-type Zeolite Composite Material for Heavy Metal Removal

Heavy metal-polluted water is of great concern to human health and the eco-environment. In situ water remediation techniques enabled by highly efficient adsorption materials are of great importance in these circumstances. Among all the materials used in water remediation, iron-based nanomaterials and porous materials are of great interest, benefiting from their rich redox reactivity and adsorption function. Here, we developed a facile protocol to directly convert the widely spread red soil in south China to fabricate the Fe2O3/faujasite (FAU)-type zeolite composite material. 
The detailed synthesis procedure and synthesis parameters, such as reaction temperature, reaction time, and the Si/Al ratio in the raw materials, have been carefully tuned. The as-synthesized composite materials show good adsorption capacity for typical heavy metal(loid) ions. With 0.001 g/mL Fe2O3/FAU-type zeolite composite material added to different heavy metal(loid)-polluted aqueous solutions (single type of heavy metal(loid) concentration: 1,000 mg/L [ppm]), the adsorption capacity was shown to be 172, 45, 170, 40, 429, 693, 94, and 133 mg/g for Cu (II), Cr (III), Cr (VI), As (III), Cd (II), Pb (II), Zn (II), and Ni (II) removal, respectively, which can be further expanded for heavy metal-polluted water and soil remediation.

Resource Recycling of Red Soil to Synthesize Fe2O3/FAU-type Zeolite Composite Material for Heavy Metal Removal

This article presents a novel and convenient route to synthesize Fe2O3/faujasite (FAU)-type zeolite composite material from red soil. The detailed synthesis parameters have been finely tuned. The obtained composite material can be used for efficient heavy metal-contaminated water remediation, indicating its potential applications in environmental engineering.

红壤资源化循环利用合成Fe2O3/FAU型重金属去除用分子筛复合材料

Heavy metal-polluted water is of great concern to human health and the eco-environment. In situ water remediation techniques enabled by highly efficient ...

环境科学

Luminescence Lifetime Imaging of O2 with a Frequency-Domain-Based Camera System

We describe a method to image dissolved oxygen (O2), in 2D at high spatial (&#60; 50-100 &#181;m) and temporal (&#60; 10 s) resolution. The method employs O2 sensitive luminescent sensor foils (planar optodes) in combination with a specialized camera system for imaging luminescence lifetime in the frequency-domain. Planar optodes are prepared by dissolving the O2-sensitive indicator dye in a polymer and spreading the mixture on a solid support in a defined thickness via knife coating. After evaporation of the solvent, the planar optode is placed in close contact with the sample of interest - here demonstrated with the roots of the aquatic plant Littorella uniflora. The O2 concentration-dependent change in the luminescence lifetime of the indicator dye within the planar optode is imaged via the backside of the transparent carrier foil and aquarium wall using a special camera. This camera measures the luminescence lifetime (&#181;s) via a shift in phase angle between a modulated excitation signal and emission signal. This method is superior to luminescence intensity imaging methods, as the signal is independent of the dye concentration or intensity of the excitation source, and solely relies on the luminescence decay time, which is an intrinsically referenced parameter. Consequently, an additional reference dye or other means of referencing are not needed. We demonstrate the use of the system for macroscopic O2 imaging of plant rhizospheres, but the camera system can also easily be coupled to a microscope.

Luminescence Lifetime Imaging of O2 with a Frequency-Domain-Based Camera System

We describe the use of a novel, frequency-domain luminescence lifetime camera for mapping 2D O2 distributions with optical sensor foils. The camera system and image analysis procedures are described along with the preparation, calibration and application of sensor foils for visualizing the O2 microenvironment in the rhizosphere of aquatic plants.

使用基于频率域的摄像机系统的 O2的发光寿命成像

We describe a method to image dissolved oxygen (O2), in 2D at high spatial (&#60; 50-100 &#181;m) and temporal (&#60; 10 s) resolution. The method employs ...

Encapsulating Cytochrome c in Silica Aerogel Nanoarchitectures without Metal Nanoparticles while Retaining Gas-phase Bioactivity

Applications such as sensors, batteries, and fuel cells have been improved through the use of highly porous aerogels when functional compounds are encapsulated within the aerogels. However, few reports on encapsulating proteins within sol&#8211;gels that are processed to form aerogels exist. A procedure for encapsulating cytochrome c (cyt. c) in silica (SiO2) sol-gels that are supercritically processed to form bioaerogels with gas-phase activity for nitric oxide (NO) is presented. Cyt. c is added to a mixed silica sol under controlled protein concentration and buffer strength conditions. The sol mixture is then gelled and the liquid filling the gel pores is replaced through a series of solvent exchanges with liquid carbon dioxide. The carbon dioxide is brought to its critical point and vented off to form dry aerogels with cyt. c encapsulated inside. These bioaerogels are characterized with UV-visible spectroscopy and circular dichroism spectroscopy and can be used to detect the presence of gas-phase nitric oxide. The success of this procedure depends on regulating the cyt. c concentration and the buffer concentration and does not require other components such as metal nanoparticles. It may be possible to encapsulate other proteins using a similar approach making this procedure important for potential future bioanalytical device development.

Encapsulating Cytochrome c in Silica Aerogel Nanoarchitectures without Metal Nanoparticles while Retaining Gas-phase Bioactivity

This procedure describes how to encapsulate cytochrome c (cyt. c) in silica (SiO2) sol-gels, process these gels to form bioaerogels, and use these bioaerogels to rapidly recognize nitric oxide (NO) through a gas-phase reaction. This type of protocol may aid in the future development of biosensors or other bioanalytical devices.

纳米银沸石复合材料作为基于发光的湿度传感器

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