This work was partially supported by JST CREST (Japan Science and Technology agency, Create REvolutionary technological seeds for Science and Technology innovation program), Grant Number JPMJCR1324, Japan.

1. Support preparation
<ol>
	<li>Pretreatment of support
	<ol>
		<li>Cut out a 3 cm long tubular porous &#945;-Al2O3 support (see Table of Materials).</li>
		<li>Wash the support with distilled water for 10 min. After that, wash the support with acetone for 10 min. Repeat this washing process 2x. 
		NOTE: Do not touch the outer surface of a support after the washing step. No other treatment was carried out (e.g., sonication, and rubbing by sandpaper, etc.)</li>
		<li>Dry the washed support at 110 &#176;C overnight prior to use for dip-coating. 
		NOTE: Measure the weight of the support piece after drying. The final membrane weight is calculated by the difference in the support weight before and after membrane synthesis.</li>
	</ol>
	</li>
</ol>
2. *BEA seed crystal synthesis
<ol>
	<li>Preparation of seed crystal synthesis gel
	<ol>
		<li>Add 26.2 g of colloidal silica (see Table of Materials) and 8.39 g of tetraethylammonium hydroxide (TEAOH) (see Table of Materials) into a 250 mL bottle made of polypropylene (Solution A). Stir the mixture using a magnetic stirrer for 20 min in a 50 &#176;C in water bath. After that, stir the mixture using a magnetic stirrer for 20 min at room temperature.</li>
		<li>Add 8.39 g of TEAOH, 5.79 g of distilled water, 1.08 g of NaOH (see Table of Materials), and 0.186 g of NaAlO2 (see Table of Materials) into a Teflon beaker (Solution B). Stir the mixture by using a magnetic stirrer for 20 min at room temperature.</li>
		<li>Add solution B to solution A in the 250 mL bottle. The mixture of solution A and B will become milky. Cap the bottle and shake it vigorously by hand for 5 min. After that, stir the mixture using a magnetic stirrer for 24 h at room temperature. The gel obtained after 24 h of stirring is called the synthesis gel. 
		NOTE: The milky solution cannot be mixed with a magnetic stirrer at first because it forms a hard gel. The 5 min shaking by hand makes the milky solution soft and allows stirring with a magnetic stirrer. The final composition of the synthesis gel is 24Na2O: 1Al2O3: 200SiO2: 60TEAOH: 2905H2O.</li>
	</ol>
	</li>
	<li>Crystallization
	<ol>
		<li>Pour the synthesis gel into a Teflon-lined autoclave. Place the autoclave in an air oven at 100 &#176;C for 7 days.</li>
	</ol>
	</li>
	<li>Quenching
	<ol>
		<li>Quench the autoclave with flowing water for 30 min after crystallization.</li>
	</ol>
	</li>
	<li>Filtration
	<ol>
		<li>Remove the white sediment in the autoclave by filtration. Wash the white sediment with 200 mL of boiling water to remove amorphous and uncrystallized materials. Dry the washed sediment at 110 &#176;C overnight. The dried sediment is the seed crystal. 
		NOTE: A 200 nm mesh filter (see Table of Materials) was used to obtain the crystal. The Si/Al ratio of obtained crystal was ~19 as analyzed by energy dispersive X-ray spectrometry (EDX). About 2.3 g of seed crystal was obtained by a single synthesis. The preparation procedure refers to a previous report by Schoeman et al. with some modifications14.</li>
	</ol>
	</li>
	<li>*BEA seed slurry preparation for dip-coating
	<ol>
		<li>Add 0.50 g of seed crystals into 100 mL of distilled water to prepare a 5 g/L seed slurry. Carry out sonication of the seed slurry for 1 h to disperse the seed crystals.</li>
	</ol>
	</li>
</ol>
3. Seeding on support by dip-coating
<ol>
	<li>Set up a support for the dip-coating equipment.
	<ol>
		<li>Fix a tubular support with a stainless steel rod using Teflon tape to plug the inside of the support.</li>
	</ol>
	</li>
	<li>Dip-coating
	<ol>
		<li>Pour the seed slurry into a glass tube with a 19 mm diameter. Immerse the fixed support into the poured seed slurry and wait for 1 min. After that, withdraw the seed slurry vertically at ~3 cm/s. Dry the support at 70 &#176;C for 2 h after dip-coating. 
		NOTE: The dip-coating process shown in 3.2.1 was run 2x. This protocol uses homemade equipment for dip-coating. One side of glass tube is plugged with a silicon cap with a tap from which the seed slurry can be withdrawn. The details about the dip-coating equipment are provided in the video.</li>
	</ol>
	</li>
	<li>3. Calcination
	<ol>
		<li>Calcine the dip-coated support at 530 &#176;C for 6 h. 
		NOTE: The calcination step was carried out to remove OSDA blocking the micropores of the seed crystals and to chemically bind the seeds onto the support surface. The increase and decrease temperature rates of the calcination step were 50 &#176;C/min.</li>
	</ol>
	</li>
	<li>Measuring the weight of the seed crystal on the support
	<ol>
		<li>After calcination, measure the weight of the support. The amount of seed crystal loaded is calculated by the difference in the support weight before and after dip-coating. 
		NOTE: The average weight of seeded crystal loaded on a support is ~17 mg.</li>
	</ol>
	</li>
</ol>
4. *BEA membrane preparation by a secondary growth method
<ol>
	<li>Preparation for gel synthesis
	<ol>
		<li>Add 92.9 g of distilled water, 9.39 g of NaOH, and 1.15 g of NaAl2O into a 250 mL polypropylene bottle. Stir the mixture using a magnetic stirrer for 30 min at 60 &#176;C in a water bath. After that, add 81.6 g of colloidal silica in a stepwise manner into the mixture. Stir the mixture by using a magnetic stirrer for 4 h at 60 &#176;C in a water bath. The gel that is obtained after stirring for 4 h is called the synthesis gel. 
		NOTE: Colloidal silica was slowly added at the rate of one drop (~0.05 g) per second. The final composition of the synthesis gel is 30Na2O: 1Al2O3: 100SiO2: 2000H2O. The preparation procedure of the synthesis gel is based on Kamimura et al. with some modifications9.</li>
	</ol>
	</li>
	<li>Crystallization
	<ol>
		<li>Pour the synthesis gel into a Teflon lined autoclave in which the seeded support is placed vertically. The autoclave is placed in an air oven at 120 &#176;C for 7 days.</li>
	</ol>
	</li>
	<li>Quenching
	<ol>
		<li>Quench the autoclave with flowing water for 30 min after crystallization.</li>
	</ol>
	</li>
	<li>Washing and drying
	<ol>
		<li>Wash the membrane in boiling water for 8 h and dry overnight. This is the *BEA membrane.</li>
	</ol>
	</li>
	<li>Measuring the weight of the membrane
	<ol>
		<li>After drying, measure the weight of the prepared membrane. The weight of the membrane is calculated by the difference in support weight before and after crystallization. 
		NOTE: The average weight of the *BEA membrane on each support is ~74 mg.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Ghaffour, N., Missimer, T. M., Amy, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technical+review+and+evaluation+of+the+economics+of+water+desalination:+Current+and+future+challenges+for+better+water+supply+sustainability.">Technical review and evaluation of the economics of water desalination: Current and future challenges for better water supply sustainability.</a> Desalination. 309, 197-207 (2013).</li><li>Hickenbottom, K. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forward+osmosis+treatment+of+drilling+mud+and+fracturing+wastewater+from+oil+and+gas+operations.">Forward osmosis treatment of drilling mud and fracturing wastewater from oil and gas operations.</a> Desalination. 312, 60-66 (2013).</li><li>Kanezashi, M., Shazwani, W. N., Yoshioka, T., Tsuru, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Separation+of+propylene/propane+binary+mixtures+by+bis(triethoxysilyl)+methane+(BTESM)-derived+silica+membranes+fabricated+at+different+calcination+temperatures.">Separation of propylene/propane binary mixtures by bis(triethoxysilyl) methane (BTESM)-derived silica membranes fabricated at different calcination temperatures.</a> Journal of Membrane Science. 415-416, 478-485 (2012).</li><li>Xu, L., Rungta, M., Koros, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Matrimid&#174;+derived+carbon+molecular+sieve+hollow+fiber+membranes+for+ethylene/ethane+separation.">Matrimid&#174; derived carbon molecular sieve hollow fiber membranes for ethylene/ethane separation.</a> Journal of Membrane Science. 380, 138-147 (2011).</li><li>Morigami, Y., Kondo, M., Abe, J., Kita, H., Okamoto, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+first+large-scale+pervaporation+plant+using+tubular-type+module+with+zeolite+NaA+membrane.">The first large-scale pervaporation plant using tubular-type module with zeolite NaA membrane.</a> Separation and Purification Technology. 25, 251-260 (2001).</li><li>Kondo, M., Komori, M., Kita, H., Okamoto, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tubular-type+pervaporation+module+with+zeolite+NaA+membrane.">Tubular-type pervaporation module with zeolite NaA membrane.</a> Journal of Membrane Science. 133, 133-141 (1997).</li><li>Hoof, V. V., Dotremont, C., Buekenhoudt, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+of+Mitsui+NaA+type+zeolite+membranes+for+the+dehydration+of+organic+solvents+in+comparison+with+commercial+polymeric+pervaporation+membranes.">Performance of Mitsui NaA type zeolite membranes for the dehydration of organic solvents in comparison with commercial polymeric pervaporation membranes.</a> Separation and Purification Technology. 48, 304-309 (2006).</li><li>Kamimura, Y., Chaikittisilp, W., Itabashi, K., Shimojima, A., Okubo, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Critical+Factors+in+the+Seed-Assisted+Synthesis+of+Zeolite+Beta+and+"Green+Beta"+from+OSDA-Free+Na+-Aluminosilicate+Gels.">Critical Factors in the Seed-Assisted Synthesis of Zeolite Beta and "Green Beta" from OSDA-Free Na+-Aluminosilicate Gels.</a> Chemistry An Asian Journal. 5, 2182-2191 (2010).</li><li>Majano, G., Delmotte, L., Valtchev, V., Mintova, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Al-Rich+Zeolite+Beta+by+Seeding+in+the+Absence+of+Organic+Template.">Al-Rich Zeolite Beta by Seeding in the Absence of Organic Template.</a> Chemistry of Materials. 21, 4184-4191 (2009).</li><li>Sakai, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+process+of+*BEA-type+zeolite+membrane+under+OSDA-free+conditions+and+its+separation+property.">Formation process of *BEA-type zeolite membrane under OSDA-free conditions and its separation property.</a> Microporous and Mesoporous Materials. 284, 360-365 (2019).</li><li>Choi, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Grain+Boundary+Defect+Elimination+in+a+Zeolite+Membrane+by+Rapid+Thermal+Processing.">Grain Boundary Defect Elimination in a Zeolite Membrane by Rapid Thermal Processing.</a> Science. 325, 590-593 (2009).</li><li>Dong, J., Lin, Y. S., Hu, M. Z. -. C., Peascoe, R. A., Payzant, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Template-removal-associated+microstructural+development+of+porous-ceramic-supported+MFI+zeolite+membranes.">Template-removal-associated microstructural development of porous-ceramic-supported MFI zeolite membranes.</a> Microporous and Mesoporous Materials. 34, 241-253 (2000).</li><li>Schoeman, B. J., Babouchkina, E., Mintova, S., Valtchev, V. P., Sterte, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Synthesis+of+Discrete+Colloidal+Crystals+of+Zeolite+Beta+and+their+Application+in+the+Preparation+of+Thin+Microporous+Films.">The Synthesis of Discrete Colloidal Crystals of Zeolite Beta and their Application in the Preparation of Thin Microporous Films.</a> Journal of Porous Materials. 8, 13-22 (2001).</li><li>Sasaki, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polytype+distributions+in+low-defect+zeolite+beta+crystals+synthesized+without+an+organic+structure-directing+agent.">Polytype distributions in low-defect zeolite beta crystals synthesized without an organic structure-directing agent.</a> Microporous and Mesoporous Materials. 225, 210-215 (2016).</li></ol>

The authors have nothing to disclose.

There are many kinds of Si and Al sources for zeolite synthesis. However, we cannot change raw materials for preparation of this *BEA-type membrane. If raw materials are changed, the phase of zeolite crystallized and/or growth rate may be changed.
Glass beakers cannot be used for synthesis gel preparation because the synthesis gel has high alkalinity. Bottles and beakers made of polyethylene, polypropylene, and Teflon can be used instead.
To prepare a higher quality...

Membrane separation has drawn attention as novel-energy saving separation process. Many types of membranes have been developed for the past decades. Polymeric membranes have been widely used for gas separation, creating drinkable water from sea water1, and wastewater treatment2.
Inorganic membrane materials like silica3, carbon molecular sieve4, and zeolite have advantages for thermal, chemical, and mechanical strength compared with polymeric membranes. Therefore, inorganic membranes tend to be used under more severe conditions, such as hydrocarbon separation in petroleum and petrochemical fields.
Zeolite has unique adsorption and molecular sieving properties due to its micropores. In addition, zeolite has a cation exchange ability that contributes to control zeolite&#39;s adsorption and molecular sieving properties. The number of cations in zeolite is determined by the Si/Al ratio of the zeolite structure. Therefore, the size of the micropores and Si/Al ratio are key characteristics that determine the permeation and separation properties of zeolite membranes. For these reasons, zeolite is a promising type of inorganic membrane material. Some zeolite membranes have already been commercialized for dehydration of organic solvents due to their hydrophilicity and molecular sieving properties5,6,7,8.
*BEA-type zeolite is an interesting membrane material because of its large pore size and wide Si/Al range. *BEA has generally been prepared by hydrothermal treatment using tetraethylammonium hydroxide as organic structure-directing agent (OSDA). However, the synthesis method using OSDA has economic and environmental disadvantages. Recently, a seed-assisted method for *BEA synthesis without using OSDA was reported9,10.
*BEA is an intergrowth crystal of polymorph A and polymorph B. Thereby, &#34;*&#34; represents an intergrowth material. At present, no bulk materials consisting only of polymorph A or B is known.
We have successfully prepared *BEA membranes without using OSDA by a modified seed-assisted method11. The *BEA membrane had very few defects and exhibited high separation performance for hydrocarbons due to its molecular sieving effect. It is well known that calcination to remove OSDA after synthesis is one of the most common causes of defect formation in zeolite membranes12,13. Our *BEA membrane prepared without using OSDA showed good separation performance possibly because this calcination step was skipped.
The preparation of zeolite membranes is based on know-how and experience accumulated in the laboratory. Consequently, it is difficult for a beginner to synthesize zeolite membranes alone. Here, we would like to share a protocol for *BEA membrane preparation as a reference for everyone who wants to start membrane synthesis.

<table><tbody><tr><td>a-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; support</td><td>Noritake Co. Ltd.</td><td>NS-1</td><td>Average pore size, 150 nm; Outer diameter, 10 mm; Innar diameter, 7 mm</td></tr><tr><td>Colloidal silica</td><td>Nissan Chemical</td><td>ST-S</td><td>SiO&lt;sub&gt;2&lt;/sub&gt; 30.5%, Na&lt;sub&gt;2&lt;/sub&gt;O 0.44%, H&lt;sub&gt;2&lt;/sub&gt;O 69.1%</td></tr><tr><td>Mesh filter (PTFE membrane)</td><td>Omnipore</td><td>JGWP04700</td><td>Pore size, 200 nm</td></tr><tr><td>NaAl&lt;sub&gt;2&lt;/sub&gt;O</td><td>Kanto Chemical</td><td>34095-01</td><td>Na&lt;sub&gt;2&lt;/sub&gt;O 31.0-35.0%; Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; 34.0-39.0%</td></tr><tr><td>NaOH</td><td>Kanto Chemical</td><td>37184-00</td><td>97%</td></tr><tr><td>Tetraethylammonium hydroxide</td><td>Sigma-Aldrich</td><td>302929-500ML</td><td>35 wt% solution</td></tr></tbody></table>

organic structure-directing agent-free synthesis for *bea-type zeolite membrane

Membrane separation has drawn attention as a novel-energy saving separation process. Zeolite membranes have great potential for hydrocarbon separation in petroleum and petrochemical fields because of their high thermal, chemical, and mechanical strength. A *BEA-type zeolite is an interesting membrane material because of its large pore size and wide Si/Al range. This manuscript presents a protocol for *BEA membrane preparation by a secondary growth method that does not use an organic structure-directing agent (OSDA). The preparation protocol consists of four steps: pretreatment of support, seed preparation, dip-coating, and membrane crystallization. First, the *BEA seed crystal is prepared by conventional hydrothermal synthesis using OSDA. The synthesized seed crystal is loaded on the outer surface of a 3 cm long tubular &#945;-Al2O3 support by a dip-coating method. The loaded seed layer is prepared with the secondary growth method using a hydrothermal treatment at 393 K for 7 days without using OSDA. A *BEA membrane having very few defects is successfully obtained. The seed preparation and dip-coating steps strongly affect the membrane quality.

Figure 1 shows the preparation procedure of the *BEA seed crystal. Figure 2 shows the X-ray diffraction (XRD) pattern of synthesized *BEA seed crystal. Typical strong reflection peaks of (101) and (302) around 2q = 7.7 and 22.1&#176; appeared. In addition, no obvious reflection peaks other than the *BEA-type zeolite were observed. These results showed that the pure phase of *BEA zeolite was successfully synthesized.
A typical...

Watch this Scientific Journal Video about Organic Structure-directing Agent-free Synthesis for *BEA-type Zeolite Membrane at JoVE.com

Organic Structure-directing Agent-free Synthesis for *BEA-type Zeolite Membrane

A *BEA seed crystal was loaded on a porous &#945;-Al2O3 support by the dip-coating method, and hydrothermally grown without using an organic structure-directing agent. A *BEA-type zeolite membrane having very few defects was successfully prepared by the secondary growth method.

Membrane separation has drawn attention as a novel-energy saving separation process. Zeolite membranes have great potential for hydrocarbon separation in ...

organic-structure-directing-agent-free-synthesis-for-bea-type-zeolite

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

14.1K Views.  Waseda University. A *BEA seed crystal was loaded on a porous α-Al2O3 support by the dip-coating method, and hydrothermally grown without using an organic structure-directing agent. A *BEA-type zeolite membrane having very few defects was successfully prepared by the secondary growth method.

Video: Organic Structure-directing Agent-free Synthesis for *BEA-type Zeolite Membrane

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Layer-by-layer Synthesis and Transfer of Freestanding Conjugated Microporous Polymer Nanomembranes

CMP as large surface area materials have attracted growing interest recently, due to their high variability in the incorporation of functional groups in combination with their outstanding thermal and chemical stability, and low densities. However, their insoluble nature causes problems in their processing since usually applied techniques such as spin coating are not available. Especially for membrane applications, where the processing of CMP as thin films is desirable, the processing problems have hindered their commercial application.
Here we describe the interfacial synthesis of CMP thin films on functionalized substrates via molecular layer-by-layer (l-b-l) synthesis. This process allows the preparation of films with desired thickness and composition and even desired composition gradients.
The use of sacrificial supports allows the preparation of freestanding membranes by dissolution of the support after the synthesis. To handle such ultra-thin freestanding membranes the protection with sacrificial coatings showed great promise, to avoid rupture of the nanomembranes. To transfer the nanomembranes to the desired substrate, the coated membranes are upfloated at the air-liquid interface and then transferred via dip coating.

In this paper we describe the interfacial synthesis of conjugated microporous polymers (CMP) on sacrificial substrates, and the dissolution of the substrate for the preparation of freestanding CMP nanomembranes. In addition, we will describe how the fragile nanomembranes can be transferred to other substrates.

CMP as large surface area materials have attracted growing interest recently, due to their high variability in the incorporation of functional groups in ...

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.

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

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.

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

Engineering

Formation of Biomembrane Microarrays with a Squeegee-based Assembly Method

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are heterogeneous mixtures of many types of lipids, contain membrane-bound proteins and are decorated with carbohydrates. In some experiments, it is desirable to decouple the biophysical or biochemical properties of the lipid bilayer from those of the natural membrane. Such cases call for the use of model systems such as giant vesicles, liposomes or supported lipid bilayers (SLBs). Arrays of SLBs are particularly attractive for sensing applications and mimicking cell-cell interactions. Here we describe a new method for forming SLB arrays. Submicron-diameter SiO2 beads are first coated with lipid bilayers to form spherical SLBs (SSLBs). The beads are then deposited into an array of micro-fabricated submicron-diameter microwells. The preparation technique uses a "squeegee" to clean the substrate surface, while leaving behind SSLBs that have settled into microwells. This method requires no chemical modification of the microwell substrate, nor any particular targeting ligands on the SSLB. Microwells are occupied by single beads because the well diameter is tuned to be just larger than the bead diameter. Typically, more 75% of the wells are occupied, while the rest remain empty. In buffer SSLB arrays display long-term stability of greater than one week. Multiple types of SSLBs can be placed in a single array by serial deposition, and the arrays can be used for sensing, which we demonstrate by characterizing the interaction of cholera toxin with ganglioside GM1. We also show that phospholipid vesicles without the bead supports and biomembranes from cellular sources can be arrayed with the same method and cell-specific membrane lipids can be identified.

Supported lipid bilayers and natural membrane particles are convenient systems that can approximate the properties of cell membranes and be incorporated in a variety of analytical strategies. Here we demonstrate a method for preparing microarrays composed of supported lipid bilayer-coated SiO2 beads, phospholipid vesicles or natural membrane particles.

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are ...

Bioengineering

Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its well-balanced ferroelectricity, piezoelectricity, and dielectric constant. In addition, BT does not contain any toxic elements. Therefore, it is considered to be an eco-friendly material, which has attracted considerable interest as a replacement for lead zirconate titanate (PZT). However, bulk BT loses its ferroelectricity at approximately 130 &#176;C, thus, it cannot be used at high temperatures. Because of the growing demand for high-temperature ferroelectric materials, it is important to enhance the thermal stability of ferroelectricity in BT. In previous studies, strain originating from the lattice mismatch at hetero-interfaces has been used. However, the sample preparation in this approach requires complicated and expensive physical processes, which are undesirable for practical applications.
In this study, we propose a chemical synthesis of a porous material as an alternative means of introducing strain. We synthesized a porous BT thin film using a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles were used as an organic template. Through a series of studies, we clarified that the introduction of pores had a similar effect on distorting the BT crystal lattice, to that of a hetero-interface, leading to the enhancement and stabilization of ferroelectricity. Owing to its simplicity and cost effectiveness, this fabrication process has considerable advantages over conventional methods.

Here, we present a protocol for the synthesis of porous barium titanate (BaTiO3) thin film by a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles are used as an organic template.

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its ...

Preparation of Functional Silica Using a Bioinspired Method

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally purify the same by acid elution. By combining sodium silicate with a polyfunctional bioinspired additive, silica is rapidly formed at ambient conditions upon neutralization. 
The effect of neutralization rate and biomolecule addition point on silica yield are investigated, and biomolecule immobilization efficiency is reported for varying addition point. In contrast to other porous silica synthesis methods, it is shown that the mild conditions required for bioinspired silica synthesis are fully compatible with the encapsulation of delicate biomolecules. Additionally, mild conditions are used across all synthesis and modification steps, making bioinspired silica a promising target for the scale-up and commercialization as both a bare material and active support medium.
The synthesis is shown to be highly sensitive to conditions, i.e., the neutralization rate and final synthesis pH, however tight control over these parameters is demonstrated through the use of auto titration methods, leading to high reproducibility in reaction progression pathway and yield. 
Therefore, bioinspired silica is an excellent active material support choice, showing versatility towards many current applications, not limited to those demonstrated here, and potency in future applications.

Here, we present a protocol to synthesize bioinspired silica materials and immobilize enzymes therein. Silica is synthesized by combining sodium silicate and an amine &#39;additive&#39;, which neutralize at a controlled rate. Material properties and function can be altered either by in situ enzyme immobilization or post-synthetic acid elution of encapsulated additives.

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally ...

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol. The growth of well-packed MOF nuclei leads to a highly intergrown polycrystalline MOF film. We show that this simple approach can be used for the synthesis of thin, intergrown zeolite imidazole framework (ZIF)-7 and ZIF-8 films. The resulting 500 nm-thick ZIF-8 membranes show a considerably high H2 permeance (8.3 x 10-6 mol m-2 s-1 Pa-1) and ideal gas selectivities (7.3 for H2/CO2, 15.5 for H2/N2, 16.2 for H2/CH4, and 2655 for H2/C3H8). An attractive performance for C3H6/C3H8 separation is also achieved (a C3H6 permeance of 9.9 x 10-8 mol m-2 s-1 Pa-1 and a C3H6/C3H8 ideal selectivity of 31.6 at 25 &#176;C). Overall, the ENACT process, owing to its simplicity, can be extended to synthesize intergrown thin films of a wide range of nanoporous crystalline materials.

A simple, reproducible, and versatile approach for the synthesis of intergrown, polycrystalline metal-organic framework membranes on a wide range of unmodified porous and non-porous supports is presented.

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and ...

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.

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

Environment

Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks

Because of their designability and unprecedented synergistic effects, core-shell metal-organic frameworks (MOFs) have been actively examined recently. However, the synthesis of single-crystalline core-shell MOFs is very challenging, and thus a limited number of examples have been reported. Here, we suggest a method of synthesizing single-crystalline HKUST-1@MOF-5 core-shells, which is HKUST-1 at the center of MOF-5. Through the computational algorithm, this pair of MOFs was predicted to have the matched lattice parameters and chemical connection points at the interface. To construct the core-shell structure, we prepared the octahedral- and cubic-shaped HKUST-1 crystals as a core MOF, in which the (111) and (001) facets were mainly exposed, respectively. Via the sequential reaction, the MOF-5 shell was well-grown on the exposed surface, showing a seamless connect interface, which resulted in the successful synthesis of single-crystalline HKUST-1@MOF-5. Their pure phase formation was proved by optical microscopic images and powder X-ray diffraction (PXRD) patterns. This method presents the potential of and insights into the single-crystalline core-shell synthesis with different kinds of MOFs.

Here, we demonstrate a protocol for the two-step synthesis of single-crystalline core-shells using a non-isostructural metal-organic framework (MOF) pair, HKUST-1 and MOF-5, which have well-matched crystal lattices.

Because of their designability and unprecedented synergistic effects, core-shell metal-organic frameworks (MOFs) have been actively examined recently. ...