The authors want to thank the Secretar&#237;a de Ciencia, Tecnolog&#237;a e Innovaci&#243;n de la Ciudad de M&#233;xico for the resources provided to carry out this work through the funded project SECITI/047/2016, and the National Funds for Scientific and Technological Development Chile (FONDECYT 11170431).

NOTE: Please read all the material safety data sheets (MSDS) before using the chemical reagents. Follow all the safety protocols by wearing a lab coat and gloves. Wear UV protection safety glasses during the photocatalysis tests. Be aware that nanomaterials may present important hazardous effects compared to their precursors.
1. Preparation of the BiOI microspheres
<ol>
	<li>For Solution 1, dissolve 2.9104 g of bismuth nitrate pentahydrate (Bi(NO3)3&#8729;5H2O) in 60 mL of ethylene glycol in a glass beaker. For Solution 2, dissolve 0.9960 g of KI in 60 mL of ethylene glycol in a glass beaker. 
	NOTE: It is important to completely dissolve the inorganic salts in organic solvent; it may take around 60 min. Sonication may be helpful to dissolve both precursors.</li>
	<li>Dropwise, add Solution 2 to Solution 1 (at a flow rate of approximately 1 mL/min). The colorless Solution 2 will change to a yellowish suspension. Sometimes, when Solution 2 is abruptly added, a black color may appear, due to the formation of the BiI4- complex. In such cases, the synthesis must be aborted and started again. 
	NOTE: Laboratory material must be completely dried since the occurrence of water promotes the uncontrolled precipitation of bismuth oxide (Bi2O3).</li>
	<li>Stir the mixture, using a moderate speed for 30 min at room temperature. Then, transfer the mixture to a 150 mL autoclave reactor. Carefully swirl the beaker to remove the remaining suspension from the sidewalls. It is possible to add 1 to 5 mL of ethylene glycol to rinse the beakers. Make sure to tightly close the reactor. 
	NOTE: The autoclave should be filled from 40% to 80% of its capacity in order to achieve the optimal pressure conditions to the formation of the BiOI microspheres. A soft seal of the reactor may result in the loss of pressure, spoiling the synthesis.</li>
	<li>Supply thermal treatment to the reactor in a furnace, from room temperature to 126 &#176;C, using a temperature ramp of 2 &#176;C/min. Maintain the final temperature for 18 h10. Then, cool the autoclave reactor to room temperature. 
	NOTE: Do not preheat the oven or provide a rapid heating since it will spoil the formation of the microspheres. 
	CAUTION: Do not induce cooling by washing the autoclave with cold water, as it may cause the deformation of the autoclave. Do not attempt to open the reactor while it is still hot, as this may result in the release of iodine gas.</li>
</ol>
2. Washing the BiOI microspheres
<ol>
	<li>Separate the solid material by decantation and wash it to remove ethylene glycol as much as possible. Prepare a filtration system consisting of a 0.8 &#956;m filter paper (Grade 5, free of ashes) properly adhered to the walls of a glass funnel. Connect&#160;to an Erlenmeyer flask using a pierced cork stopper. Carry out the filtration step by gravity.
	<ol>
		<li>(Optional) When pouring the suspension from the reactor to the funnel, use deionized water to rinse the autoclave reactor.</li>
	</ol>
	</li>
	<li>Wash the solid product retained in the filter paper&#8212;of an intense orange color&#8212;several times with distilled water and absolute ethanol (technical grade). Alternate the washing solvent until the leachate is colorless. 
	NOTE: Please note that deionized water removes inorganic ions, while absolute ethanol removes the remaining ethylene glycol; thus, both solvents must be used.</li>
	<li>Use deionized water in the two last washing steps to remove any trace of absolute ethanol and dry the intense-orange-colored product at 80 &#176;C for 24 h. Last, store the material in amber glass bottles, in the dark, preferably in a desiccator.</li>
</ol>
3. Characterization of the BiOI microspheres
<ol>
	<li>Perform the X-ray diffraction analysis of the powder material, using a monochromic Cu-K&#945; light source, with &#955; = 1.5406 &#197;, operated at 30 kV and 15 mA.</li>
	<li>Determine the specific surface area by the Brunauer&#8211;Emmett&#8211;Teller (BET) method, via the adsorption of N2.
	<ol>
		<li>Outgas the powder samples (500 mg) at 80&#186;C overnight prior to analysis. Perform the N2 adsorption measurements at -75&#186;C. Calculate the specific surface area and the pore volume from the adsorption isotherms.</li>
	</ol>
	</li>
	<li>Determine the UV-visible diffuse reflectance spectra of the materials using a spectrophotometer with a praying mantis accessory.
	<ol>
		<li>Dry the powder samples, in a laboratory oven, at 105&#186;C overnight. Then, carefully put 30 mg in the sample port of the praying mantis accessory.</li>
		<li>Irradiate the powder samples with a light source within the range of 200 to 800 nm in order to obtain the light absorption spectrum of the material. Calculate the band gap energy (Eg) using the absorption spectrum of the sample.</li>
	</ol>
	</li>
	<li>Determine the secondary size of the BiOI microspheres by scanning electron microscopy.
	<ol>
		<li>Put the powder sample on a carbon tape and then in the microscope stub to perform the observations.</li>
		<li>Determine the chemical composition of the samples by energy dispersive X-ray spectroscopy (EDS) analysis.</li>
	</ol>
	</li>
</ol>
4. Photocatalytic activity test
<ol>
	<li>For the test solution, dissolve 7.5 mg of ciprofloxacin in 250 mL of distilled water, to obtain a 30 ppm solution. Then, transfer the test solution to the glass photocatalytic reactor. Thoroughly stir the solution, with a magnetic stirrer, keeping the temperature at 25 &#176;C. Bubble air to the solution at 100 mL/min in order to maintain air saturation.</li>
	<li>Add 62.5 mg of the BiOI photocatalyst to the test solution to achieve a concentration of 0.25 g/L. Immediately, take the first sample (8 mL) using a glass syringe. After 30 min of stirring in the dark, take the second sample and turn the light source on.
	<ol>
		<li>Given that the experiments are performed under UV-A/visible light conditions, use a 70 W lamp in the photocatalysis tests. Locate the light source 5 cm above the photoreactor.</li>
	</ol>
	</li>
	<li>Take liquid samples (8 mL) after 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, and 300 min of irradiation. Filter all the withdrawn samples by passing them through a 0.22 &#181;m nylon membrane, in order to remove any solid particle from the liquid prior to analysis. Store the filtered samples in amber glass vials at 4 &#176;C until analysis.</li>
	<li>Determine the mineralization of ciprofloxacin by analyzing the total organic carbon (TOC) concentration remaining in the liquid samples throughout the photocatalytic process.
	<ol>
		<li>Measure the concentration of total carbon (TC, in mg/L) via wet combustion at 720 &#176;C, in the presence of a Pt catalyst and air atmosphere. Under such conditions, all the carbon is oxidized to CO2 and quantified in an FTIR detector coupled to the TOC device.</li>
		<li>Determine the inorganic carbon concentration (IC, in mg/L) via acidification of&#160;samples with 1 M HCl, leading to the conversion of carbonate and bicarbonate to CO2&#183;H2O, which is quantified in the FTIR detector.</li>
		<li>Calculate the concentration of TOC remaining in water samples by the following equation. 
		<img alt="Equation" src="/files/ftp_upload/59006/59006eq1.jpg" /> 
		&#8203;NOTE: In order to avoid interferences and, thus, incorrect results, it is very important to remove any trace of organic impurities by thoroughly cleaning all the glass material used in the sample preparation. This may be warranted by washing several times with hot water.</li>
		<li>Calculate the mineralization yield via the depletion of total organic carbon throughout the reaction using the equation: 
		<img alt="Equation" src="/files/ftp_upload/59006/59006eq2v2.jpg" /> 
		Here, TOCo is the concentration of total organic carbon at the beginning of the irradiation, while TOC is the concentration of total organic carbon at any time of the photocatalytic reaction.</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

We consider the mixture of the precursors as the critical step in the solvothermal synthesis of the BiOI microspheres. A very slow dripping of the KI solution into the Bi(NO3)3 solution (at a maximum of 1 mL/min) is crucial to obtain mesoporous microspheres, since it allows the slow formation and self-assembly of the [Bi2O2]+2 slabs, followed by the bonding with the iodide atoms to form the BiOI laminates. The lamellae are the bricks of the microspheres in the solvot...

A plethora of semiconductors has been synthesized so far, aiming for photocatalysts with high activity under visible light irradiation, either to degrade organic compounds or to generate renewable energy in the form of hydrogen1,2. Bismuth oxyhalides BiOX (X = Cl, Br, or I) are candidates for such applications because of their high photocatalytic efficiency under visible light or simulated sunlight irradiation3,4. The band gap energy (Eg) of bismuth oxyhalides decreases with the increase of the atomic number of the halide; thus, BiOI is the material displaying the lowest activation energy (Eg = 1.8 eV)5. Iodide atoms, bonded via Van der Waals force to bismuth atoms, create an electric field that favors the migration of the charge carriers to the semiconductor surface, triggering the photocatalytic process4,6. Moreover, the architecture of the crystallite has a critical role in the separa,tion of the charge carriers. Highly oriented structures in the (001) plane and 3D structures (such as microspheres) facilitate the charge carrier separation upon irradiation, increasing the photocatalytic performance7,8,9,10,11,12. In light of this, it is necessary to develop reliable synthetic methods to obtain structures that boost the photo-activity of the bismuth oxyhalide materials.
The solvothermal method is, by far, the most commonly used and studied route to obtain BiOI microspheres13,14,15,16. Some methodologies using ionic liquids have been also reported17, although the expenses associated with these methodologies can be higher. Microsphere structure is usually obtained using organic solvents such as ethylene glycol, which acts as a coordinating agent to form metallic alkoxides, resulting in a gradual self-assembling of [Bi2O2]2+ species18,19. Using the solvothermal route with ethylene glycol facilitates the formation of different morphologies by changing the key parameters in the reaction, such as temperature and reaction time4,18. There is a wide body of literature on synthetic methods to obtain BiOI microspheres, which shows contrasting information to achieve highly photoactive structures. This detailed protocol is aimed at showing a reliable synthetic method to obtain BiOI microspheres highly functional in the photocatalytic degradation of pollutants in water. We intend to help new researchers to successfully obtain this kind of materials, avoiding the most common pitfalls associated with the synthesis process.

<table>
	<tbody>
		<tr>
			<td>Bismuth(III) nitrate pentahydrate</td>
			<td>Sigma Aldrich</td>
			<td>383074</td>
			<td>ACS reagent, &#8805;98.0%</td>
		</tr>
		<tr>
			<td>Potassium iodide</td>
			<td>Sigma Aldrich</td>
			<td>746428</td>
			<td>ACS reagent, &#8805;98.0%</td>
		</tr>
		<tr>
			<td>Ethylene glycol</td>
			<td>Sigma Aldrich</td>
			<td>324558</td>
			<td>Anhydrous, 99.8%</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Meyer</td>
			<td>5405</td>
			<td>Technical Grade, 96%</td>
		</tr>
		<tr>
			<td>Ciprofloxacin</td>
			<td>Sigma Aldrich</td>
			<td>17850</td>
			<td>HPLC, &#8805;98.0%</td>
		</tr>
		<tr>
			<td>Cary 5000 UV-Vis-NIR spectrophotometer</td>
			<td>Agilent</td>
			<td></td>
			<td>Used for the Band gap determination by the Tauc model.</td>
		</tr>
		<tr>
			<td>JSM-5600 Scanning Electron Microscope</td>
			<td>JOEL</td>
			<td></td>
			<td>Used for the SEM images.</td>
		</tr>
		<tr>
			<td>Autosob-1</td>
			<td>Qantachrome Instruments</td>
			<td></td>
			<td>Used for the determination of surface area and pore diameter.</td>
		</tr>
		<tr>
			<td>TOC-L Total Organic Carbon Analyzer</td>
			<td>Shimadzu</td>
			<td></td>
			<td>Used for determination of total organic carbon in water samples.</td>
		</tr>
		<tr>
			<td>Bruker AXS D8 Advance - X-ray Diffraction</td>
			<td>Bruker</td>
			<td></td>
			<td>Determination of crystal structure and crystallite size</td>
		</tr>
	</tbody>
</table>

a facile synthetic method to obtain bismuth oxyiodide microspheres highly functional for the photocatalytic processes of water depuration

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of materials is highly related to its photocatalytic performance, it is necessary to standardize the synthetic methods in order to obtain the most functional architectures and, thus, the highest photocatalytic efficiency. Here, we report a reliable route to obtain BiOI microspheres via the solvothermal process, using Bi(NO3)3 and potassium iodide (KI) as precursors, and ethylene glycol as a template. The synthesis is standardized in a 150 mL autoclave, at 126 &#176;C for 18 h. This results in 2-3 &#181;m-sized mesoporous microspheres, with a relevant specific surface area (61.3 m2/g). Shortening the reaction times in the synthesis results in amorphous structures, while higher temperatures lead to a slight increase in the porosity of the microspheres, with no effect in the photocatalytic performance. The materials are photo-active under UV-A/visible light irradiation for the degradation of the antibiotic ciprofloxacin in water. This method has demonstrated to be effective in interlaboratory tests, obtaining similar BiOI microspheres in Mexican and Chilean research groups.

3D microstructures of BiOI were successfully synthesized by the proposed synthetic method. This was confirmed by the SEM images shown in Figure 1a-c. The microspheres are formed from laminar structures of [Bi2O2]2+, which are bonded by two iodide atoms1. The formation of the microspheres depends on the temperature and time of the solvothermal procedure, as these paramet...

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A Facile Synthetic Method to Obtain Bismuth Oxyiodide Microspheres Highly Functional for the Photocatalytic Processes of Water Depuration

This article describes a synthetic method to obtain bismuth oxyiodide microspheres, which are highly functional to perform the photocatalytic removal of organic pollutants, such as ciprofloxacin, in water under UV-A/visible light irradiation.

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of ...

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Chemistry

7.6K Views.  Universidad Nacional Autónoma de México. This article describes a synthetic method to obtain bismuth oxyiodide microspheres, which are highly functional to perform the photocatalytic removal of organic pollutants, such as ciprofloxacin, in water under UV-A/visible light irradiation.

Video: A Facile Synthetic Method to Obtain Bismuth Oxyiodide Microspheres Highly Functional for the Photocatalytic Processes of Water Depuration

Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues

Protein alignments are commonly used to evaluate the similarity of protein residues, and the derived consensus sequence used for identifying functional units (e.g., domains). Traditional consensus-building models fail to account for interpositional dependencies &#8211; functionally required covariation of residues that tend to appear simultaneously throughout evolution and across the phylogentic tree. These relationships can reveal important clues about the processes of protein folding, thermostability, and the formation of functional sites, which in turn can be used to inform the engineering of synthetic proteins. Unfortunately, these relationships essentially form sub-motifs which cannot be predicted by simple &#8220;majority rule&#8221; or even HMM-based consensus models, and the result can be a biologically invalid &#8220;consensus&#8221; which is not only never seen in nature but is less viable than any extant protein. We have developed a visual analytics tool, StickWRLD, which creates an interactive 3D representation of a protein alignment and clearly displays covarying residues. The user has the ability to pan and zoom, as well as dynamically change the statistical threshold underlying the identification of covariants. StickWRLD has previously been successfully used to identify functionally-required covarying residues in proteins such as Adenylate Kinase and in DNA sequences such as endonuclease target sites.

Synthetic protein sequences based on consensus motifs typically ignore co-evolving residues, that imply interpositional dependencies (IPDs). IPDs can be essential to activity, and designs that disregard them may result in suboptimal results. This protocol uses StickWRLD to identify IPDs and help inform rational protein design, resulting in more efficient results.

Protein alignments are commonly used to evaluate the similarity of protein residues, and the derived consensus sequence used for identifying functional ...

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

Highly Stable, Functional Hairy Nanoparticles and Biopolymers from Wood Fibers: Towards Sustainable Nanotechnology

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While metal-based nanoparticles are associated with synthetic and environmental hassles, cellulose introduces a green, sustainable alternative for nanoparticle synthesis. Here, we present the chemical synthesis and separation procedures to produce new classes of hairy nanoparticles (bearing both amorphous and crystalline regions) and biopolymers based on wood fibers. Through periodate oxidation of soft wood pulp, the glucose ring of cellulose is opened at the C2-C3 bond to form 2,3-dialdehyde groups. Further heating of the partially oxidized fibers (e.g., T = 80 &#176;C) results in three products, namely fibrous oxidized cellulose, sterically stabilized nanocrystalline cellulose (SNCC), and dissolved dialdehyde modified cellulose (DAMC), which are well separated by intermittent centrifugation and co-solvent addition. The partially oxidized fibers (without heating) were used as a highly reactive intermediate to react with chlorite for converting almost all aldehyde to carboxyl groups. Co-solvent precipitation and centrifugation resulted in electrosterically stabilized nanocrystalline cellulose (ENCC) and dicarboxylated cellulose (DCC). The aldehyde content of SNCC and consequently surface charge of ENCC (carboxyl content) were precisely controlled by controlling the periodate oxidation reaction time, resulting in highly stable nanoparticles bearing more than 7 mmol functional groups per gram of nanoparticles (e.g., as compared to conventional NCC bearing &#60;&#60; 1 mmol functional group/g). Atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) attested to the rod-like morphology. Conductometric titration, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), electrokinetic-sonic-amplitude (ESA) and acoustic attenuation spectroscopy shed light on the superior properties of these nanomaterials.

Synthesis schemes to prepare highly stable wood fiber-based hairy nanoparticles and functional cellulose-based biopolymers have been detailed.

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

This detailed protocol describes the new Spin Saturation Transfer Difference Nuclear Magnetic Resonance protocol (SSTD NMR), recently developed in our group to study processes of mutual-site chemical exchange that are difficult to analyze by traditional methods. As the name suggests, this method combines the Spin Saturation Transfer method used for small molecules, with the Saturation Transfer Difference (STD) NMR method employed for the study of protein-ligand interactions, by measuring transient spin saturation transfer along increasing saturation times (build-up curves) in small organic and organometallic molecules undergoing chemical exchange.
Advantages of this method over existing ones are: there is no need to reach coalescence of the exchanging signals; the method can be applied as long as one signal of the exchanging sites is isolated; there is no need to measure T1 or reach steady state saturation; rate constant values are measured directly, and T1 values are obtained in the same experiment, using only one set of experiments.
To test the method, we have studied the dynamics of the hindered rotation of N,N-dimethylamides, for which much data is available for comparison. The thermodynamic parameters obtained using SSTD are very similar to the reported ones (spin-saturation transfer techniques and line-shape analysis). The method can be applied to more challenging substrates that cannot be studied by previous methods.
We envisage that the simple experimental set up and the wide applicability of the method to a great variety of substrates will make this a common technique amongst organic and organometallic chemists without extensive expertise in NMR.

Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

A detailed protocol describing the SSTD NMR method is presented here to help new users apply this new method to obtain the kinetic parameters of their own systems undergoing chemical exchange.

This detailed protocol describes the new Spin Saturation Transfer Difference Nuclear Magnetic Resonance protocol (SSTD NMR), recently developed in our ...

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.

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

The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance

The chemical bonding of particulate photocatalysts to supporting material surfaces is of great importance in engineering more efficient and practical photocatalytic structures. However, the influence of such chemical bonding on the optical and surface properties of the photocatalyst and thus its photocatalytic activity/reaction selectivity behavior has not been systematically studied. In this investigation, TiO2 has been supported on the surface of SiO2 by means of two different methods: (i) by the in situ formation of TiO2 in the presence of sand quartz via a sol-gel method employing tetrabutyl orthotitanium (TBOT); and (ii) by binding the commercial TiO2 powder to quartz on a surface silica gel layer formed from the reaction of quartz with tetraethylorthosilicate (TEOS). For comparison, TiO2 nanoparticles were also deposited on the surfaces of a more reactive SiO2 prepared by a hydrolysis-controlled sol-gel technique as well as through a sol-gel route from TiO2 and SiO2 precursors. The combination of TiO2 and SiO2, through interfacial Ti-O-Si bonds, was confirmed by FTIR spectroscopy and the photocatalytic activities of the obtained composites were tested for photocatalytic degradation of NO according to the ISO standard method (ISO 22197&#8722;1). The electron microscope images of the obtained materials showed that variable photocatalyst coverage of the support surface can successfully be achieved but the photocatalytic activity towards NO removal was found to be affected by the preparation method and the nitrate selectivity is adversely affected by Ti-O-Si bonding.

The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance

The focus of the present work is to establish means to generate and quantify levels of Ti-O-Si linkages and to correlate these with the photocatalytic properties of the supported TiO2.

The chemical bonding of particulate photocatalysts to supporting material surfaces is of great importance in engineering more efficient and practical ...

Color Spot Test As a Presumptive Tool for the Rapid Detection of Synthetic Cathinones

Synthetic cathinones are a large class of new psychoactive substances (NPS) that are increasingly prevalent in drug seizures made by law enforcement and other border protection agencies globally. Color testing is a presumptive identification technique indicating the presence or absence of a particular drug class using rapid and uncomplicated chemical methods. Owing to their relatively recent emergence, a color test for the specific identification of synthetic cathinones is not currently available. In this study, we introduce a protocol for the presumptive identification of synthetic cathinones, employing three aqueous reagent solutions: copper(II) nitrate, 2,9-dimethyl-1,10-phenanthroline (neocuproine) and sodium acetate. Small pin-head sized amounts (approximately 0.1-0.2 mg) of the suspected drugs are added to the wells of a porcelain spot plate, and each reagent is then added dropwise sequentially before heating on a hotplate. A color change from very light blue to yellow-orange after 10 min indicates the likely presence of synthetic cathinones. The highly stable and specific test reagent has the potential for use in the presumptive screening of unknown samples for synthetic cathinones in a forensic laboratory. However, the nuisance of an added heating step for the color change result limits the test to laboratory application and decreases the likelihood of an easy translation to field testing.

Here we present a simple, inexpensive, and selective chemical spot test protocol for the detection of synthetic cathinones, a class of new psychoactive substances. The protocol is suitable for use in various areas of law enforcement that encounter illicit material.

Synthetic cathinones are a large class of new psychoactive substances (NPS) that are increasingly prevalent in drug seizures made by law enforcement and ...

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 ...