Name: a facile synthetic method to obtain bismuth oxyiodide microspheres highly functional for the photocatalytic processes of water depuration
Uploaded: 2019-03-29T12:30:00
Description: Watch this Scientific Journal Video about A Facile Synthetic Method to Obtain Bismuth Oxyiodide Microspheres Highly Functional for the Photocatalytic Processes of Water Depuration at JoVE.com

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&#87...

<ol>
	<li>Yu, C., Zhou, W., Liu, H., Liu, Y., Dionysiou, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+fabrication+of+microsphere+photocatalysts+for+environmental+purification+and+energy+conversion.">Design and fabrication of microsphere photocatalysts for environmental purification and energy conversion.</a> Chemical Engineering Journal. 287, 117-129 (2016).</li><li>Wang, H., 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=Semiconductor+heterojunction+photocatalysts:+Design,+construction,+and+photocatalytic+performances.">Semiconductor heterojunction photocatalysts: Design, construction, and photocatalytic performances.</a> Chemical Society Reviews. 43 (15), 5234-5244 (2014).</li><li>Chou, S. Y., Chen, C. C., Dai, Y. M., Lin, J. H., Lee, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+synthesis+of+bismuth+oxyiodide/graphitic+carbon+nitride+nanocomposites+with+enhanced+visible-light+photocatalytic+activity.">Novel synthesis of bismuth oxyiodide/graphitic carbon nitride nanocomposites with enhanced visible-light photocatalytic activity.</a> RSC Advances. 6, 33478-33491 (2016).</li><li>Siao, C. W., 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=Controlled+hydrothermal+synthesis+of+bismuth+oxychloride/bismuth+oxybromide/bismuth+oxyiodide+composites+exhibiting+visible-light+photocatalytic+degradation+of+2-hydroxybenzoic+acid+and+crystal+violet.">Controlled hydrothermal synthesis of bismuth oxychloride/bismuth oxybromide/bismuth oxyiodide composites exhibiting visible-light photocatalytic degradation of 2-hydroxybenzoic acid and crystal violet.</a> Journal of Colloid and Interface Science. 526, 322-336 (2018).</li><li>Meng, X., Zhang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bismuth-based+photocatalytic+semiconductors:+Introduction,+challenges+and+possible+approaches.">Bismuth-based photocatalytic semiconductors: Introduction, challenges and possible approaches.</a> Journal of Molecular Catalysis A: Chemical. 423, 533-549 (2016).</li><li>Wang, Y., Deng, K., Zhang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visible+light+photocatalysis+of+BiOI+and+its+photocatalytic+activity+enhancement+by+in+situ+ionic+liquid+modification.">Visible light photocatalysis of BiOI and its photocatalytic activity enhancement by in situ ionic liquid modification.</a> Journal of Physical Chemistry C. 115 (29), 14300-14308 (2011).</li><li>Xiao, X., Zhang, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=De+Facile+synthesis+of+nanostructured+BiOI+microspheres+with+high+visible+light-induced+photocatalytic+activity.">De Facile synthesis of nanostructured BiOI microspheres with high visible light-induced photocatalytic activity.</a> Journal of Materials Chemistry. 20 (28), 5866-5870 (2010).</li><li>Chen, C. C., 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=Bismuth+oxyfluoride/bismuth+oxyiodide+nanocomposites+enhance+visible-light-driven+photocatalytic+activity.">Bismuth oxyfluoride/bismuth oxyiodide nanocomposites enhance visible-light-driven photocatalytic activity.</a> Journal of Colloid and Interface Science. 532, 375-386 (2018).</li><li>Xia, 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=Self-assembly+and+enhanced+photocatalytic+properties+of+BiOI+hollow+microspheres+via+a+reactable+ionic+liquid.">Self-assembly and enhanced photocatalytic properties of BiOI hollow microspheres via a reactable ionic liquid.</a> Langmuir. 27 (3), 1200-1206 (2011).</li><li>Mera, A. C., Contreras, D., Escalona, N., Mansilla, H. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BiOI+microspheres+for+photocatalytic+degradation+of+gallic+acid.">BiOI microspheres for photocatalytic degradation of gallic acid.</a> Journal of Photochemistry and Photobiology A: Chemistry. 318, 71-76 (2016).</li><li>Pan, M., Zhang, H., Gao, G., Liu, L., Chen, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Facet-dependent+catalytic+activity+of+nanosheet-assembled+bismuth+oxyiodide+microspheres+in+degradation+of+bisphenol+A.">Facet-dependent catalytic activity of nanosheet-assembled bismuth oxyiodide microspheres in degradation of bisphenol A.</a> Environmental Science and Technology. 49 (10), 6240-6248 (2015).</li><li>Hu, 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=Solvents+mediated-synthesis+of+BiOI+photocatalysts+with+tunable+morphologies+and+their+visible-light+driven+photocatalytic+performances+in+removing+of+arsenic+from+water.">Solvents mediated-synthesis of BiOI photocatalysts with tunable morphologies and their visible-light driven photocatalytic performances in removing of arsenic from water.</a> Journal of Hazardous Materials. 264, 293-302 (2014).</li><li>Ye, L., Su, Y., Jin, X., Xie, H., Zhang, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+BiOX+(X+=+Cl,+Br+and+I)+photocatalysts:+Synthesis,+modification,+facet+effects+and+mechanisms.">Recent advances in BiOX (X = Cl, Br and I) photocatalysts: Synthesis, modification, facet effects and mechanisms.</a> Environmental Science: Nano. 1 (2), 90-112 (2014).</li><li>Qin, X., 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=Three+dimensional+BiOX+(X=Cl,+Br+and+I)+hierarchical+architectures:+Facile+ionic+liquid-assisted+solvothermal+synthesis+and+photocatalysis+towards+organic+dye+degradation.">Three dimensional BiOX (X=Cl, Br and I) hierarchical architectures: Facile ionic liquid-assisted solvothermal synthesis and photocatalysis towards organic dye degradation.</a> Materials Letters. 100, 285-288 (2013).</li><li>Chou, S. 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=A+series+of+BiO+x+I+y/GO+photocatalysts:+synthesis,+characterization,+activity,+and+mechanism.">A series of BiO x I y/GO photocatalysts: synthesis, characterization, activity, and mechanism.</a> RSC Advances. 6 (86), 82743-82758 (2016).</li><li>Shi, X., Chen, X., Chen, X., Zhou, S., Lou, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solvothermal+synthesis+of+BiOI+hierarchical+spheres+with+homogeneous+sizes+and+their+high+photocatalytic+performance.">Solvothermal synthesis of BiOI hierarchical spheres with homogeneous sizes and their high photocatalytic performance.</a> Materials Letters. 68, 296-299 (2012).</li><li>Di, 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=Reactable+ionic+liquid-assisted+rapid+synthesis+of+BiOI+hollow+microspheres+at+room+temperature+with+enhanced+photocatalytic+activity.">Reactable ionic liquid-assisted rapid synthesis of BiOI hollow microspheres at room temperature with enhanced photocatalytic activity.</a> Journal of Materials Chemistry A. 2 (38), 15864-15874 (2014).</li><li>Ren, K., 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=Controllable+synthesis+of+hollow/flower-like+BiOI+microspheres+and+highly+efficient+adsorption+and+photocatalytic+activity.">Controllable synthesis of hollow/flower-like BiOI microspheres and highly efficient adsorption and photocatalytic activity.</a> CrystEngComm. 14 (13), 4384-4390 (2012).</li><li>Lei, 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=Room+temperature,+template-free+synthesis+of+BiOI+hierarchical+structures:+Visible-light+photocatalytic+and+electrochemical+hydrogen+storage+properties.">Room temperature, template-free synthesis of BiOI hierarchical structures: Visible-light photocatalytic and electrochemical hydrogen storage properties.</a> Dalton Transactions. 39 (13), 3273-3278 (2010).</li><li>Montoya-Zamora, J. M., Mart&#237;nez-de la Cruz, A., L&#243;pez Cu&#233;llar, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+photocatalytic+activity+of+BiOI+synthesized+in+presence+of+EDTA.">Enhanced photocatalytic activity of BiOI synthesized in presence of EDTA.</a> Journal of the Taiwan Institute of Chemical Engineers. 75, 307-316 (2017).</li><li>He, R., Zhang, J., Yu, J., Cao, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Room-temperature+synthesis+of+BiOI+with+tailorable+(0+0+1)+facets+and+enhanced+photocatalytic+activity.">Room-temperature synthesis of BiOI with tailorable (0 0 1) facets and enhanced photocatalytic activity.</a> Journal of Colloid and Interface Science. 478, 201-208 (2016).</li><li>Song, J. M., Mao, C. J., Niu, H. L., Shen, Y. H., Zhang, S. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hierarchical+structured+bismuth+oxychlorides:+self-assembly+from+nanoplates+to+nanoflowers+via+a+solvothermal+route+and+their+photocatalytic+properties.">Hierarchical structured bismuth oxychlorides: self-assembly from nanoplates to nanoflowers via a solvothermal route and their photocatalytic properties.</a> CrystEngComm. 12, 3875-3881 (2010).</li><li>Mera, A. C., V&#225;ldes, H., Jamett, F. J., Mel&#233;ndrez, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BiOBr+microspheres+for+photocatalytic+degradation+of+an+anionic+dye.">BiOBr microspheres for photocatalytic degradation of an anionic dye.</a> Solid State Science. 65, 15-21 (2017).</li><li>Kong, X. Y., Lee, W. C., Ong, W. J., Chai, S. P., Mohamed, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxygen-deficient+BiOBr+as+a+highly+stable+photocatalyst+for+efficient+CO2+reduction+into+renewable+carbon-neutral+fuels.">Oxygen-deficient BiOBr as a highly stable photocatalyst for efficient CO2 reduction into renewable carbon-neutral fuels.</a> ChemCatChem. 8, 3074-3081 (2016).</li></ol>

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...

Watch this Scientific Journal Video about A Facile Synthetic Method to Obtain Bismuth Oxyiodide Microspheres Highly Functional for the Photocatalytic Processes of Water Depuration at JoVE.com

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 ...

This protocol provides a reliable method to synthesize bismuth oxyiodide microspheres which are photocatalytically active under visible light irradiation. Here we present the key parameters that result in a successful synthesis of this kind of 3D structure via the solvothermal method. One of the main advantages of this method is that by varying key parameters such as temperature and time of heating, it is possible to obtain different structures.Microsphere leaf and flower-like structures have been obtained for instance. Through this method, it is possible to obtain photocatalytically active materials which have demonstrated to efficiently remove organic pollutants, bacteria and even heavy materials in polluted waters. To a higher scale, it is possible to use photocatalysis to clean water for human consumption.This method can provide some insights on the synthesis of other bismuth-based materials which have been reported as efficient in other catalysis reactions such as the oxidation of carbon monoxide as well as in artificial photosynthesis. To start preparing solution one, dissolve 2.9 grams of bismuth nitrate pentahydrate in 60 milliliters of ethylene glycol in a glass beaker. For solution two, dissolve one gram of potassium iodide in 60 milliliters of ethylene glycol in a glass beaker.Use a micropipette to add solution two to solution one drop by drop at a flow rate of one milliliter per minute to create a yellowish suspension. Abrupt addition of solution two will create a black color due to formation of bismuth tetraiodide anion. In such case, the synthesis must be aborted and started again.While making the precursor, it is necessary to wait until the disappearance of the yellow color from around the dripping solution before adding the next step of the potassium iodide to the bismuth solution. After stirring the mixture for 30 minutes at room temperature, transfer the mixture to a 150 milliliter autoclave reactor. Use ethylene glycol to rinse the beaker, swirl the beaker to remove the remaining suspension from the sidewalls, and tightly close the reactor.Place the autoclave reactor in a furnace. Set the temperature to 126 degrees Celsius at a temperature ramp of two degrees per minute and keep the reactor in the furnace for 18 hours. After that, take the autoclave reactor out of the furnace to cool down.Do not open hot reactor to avoid release of iodine gas. Adhere a 0.8 micrometer filter paper to the walls of a glass funnel. Pour the suspension from the reactor into the funnel and use ethylene glycol to rinse the reactor.Use deionized water and absolute ethanol to wash the solid retained on the filter for removing inorganic ions and ethylene glycol respectively. Alternate the washing solvent until the leachate is colorless. Use deionized water as the last washing step to remove any trace of ethanol.Place the product in the oven and set at 80 degrees Celsius for 24 hours. After that, separate the powder material from the filter to homogenize in an agate mortar. Then transfer the material into amber glass bottles in a desiccator.Put 30 milligrams of the samples into the sample port of the praying mantis accessory of the spectrophotometer. With a light source of 200 to 800 nanometers, irradiate the powder samples and continue as described in the manuscript. Band gap value obtained via this characterization would be around 1.8 electron volts.To make the 30 parts per million test solution, dissolve 7.5 milligrams of ciprofloxacin in 250 milliliters of distilled water. Then transfer the test solution to the photocatalytic reactor and thoroughly stir the solution at 25 degrees Celsius on a magnetic stir. From a pipeline, bubble dry air from a tank to the solution at 100 milliliters per minute to maintain air saturation.Position a 70 watt lamp at a five centimeters distance above the photoreactor. Add 62.5 milligrams of the bismuth oxyiodide microspheres to the test solution to achieve a load of 0.25 grams per liter. Immediately, use a glass syringe to take eight milliliters of the sample.Use a glass syringe to take the second eight milliliter sample for measuring the absorption of the organic molecule on the bismuth oxyiodide surface and then turn on the light. Take 12 samples after irradiation at the desired irradiation periods. Filter all the withdrawn samples by passing them through a nylon membrane.Store the filtered samples in glass vials at four degrees Celsius. Load the glass vials into the TOC device. This equipment analyzes the concentration of total and inorganic carbon remaining in the liquid samples through an infrared detector.3D microstructures of bismuth oxyiodide were successfully synthesized by the proposed synthetic method. SEM images show perfectly shaped spherical structures obtained by the solvothermal treatment at 126 degrees Celsius for 18 hours. Amorphous structures were observed when the solvothermal treatment was performed at 130 degrees Celsius for only 12 hours.Mesoporous microspheres of bismuth oxyiodide were achieved when a treatment was performed at 160 degrees for 18 hours. X-ray diffraction patterns of the bismuth oxyiodide microspheres obtained with 18-hour thermal treatment at 126 degrees Celsius and 160 degrees Celsius as well as a 0D bismuth oxyiodide material were compared. The decay in the peak intensity along with the broadening of the diffraction patterns showed the loss of orientation of the crystals when microspheres were obtained.The photocatalytic activity of the microspheres was assessed through the degradation of ciprofloxacin in pure water under UVA visible light irradiation. The bismuth oxyiodide washed with both ethanol and water showed higher mineralization rate than bismuth oxyiodide washed only with water. Photolysis was unable to completely oxidize the organic molecule.Please remember bismuth oxyiodide precursors are very unique. Thus, the addition of the iodide to the bismuth solution must be slow giving us a result the formation of the microsphere structures. Microspheres obtained by this method can be used in other environmental photocatalysis lines.It is necessary to test their capacity introduction reactions to produce hydrogen and also to reduce heavy metals in water. The development of this procedure paved the way to synthesize other 3D bismuth oxyiodide such as bismuth oxychloride or bismuth oxybromide which are known to potentially produce highly oxidative species.

a-facile-synthetic-method-to-obtain-bismuth-oxyiodide-microspheres

Research

JoVE Journal

Chemistry

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 ...

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 ...

Synthesis of a Water-soluble Metal&#8211;Organic Complex Array

We demonstrate a method for the synthesis of a water-soluble multimetallic peptidic array containing a predetermined sequence of metal centers such as Ru(II), Pt(II), and Rh(III). The compound, named as a water-soluble metal-organic complex array (WSMOCA), is obtained through 1) the conventional solution-chemistry-based preparation of the corresponding metal complex monomers having a 9-fluorenylmethyloxycarbonyl (Fmoc)-protected amino acid moiety and 2) their sequential coupling together with other water-soluble organic building units on the surface-functionalized polymeric resin by following the procedures originally developed for the solid-phase synthesis of polypeptides, with proper modifications. Traces of reactions determined by mass spectrometric analysis at the representative coupling steps in stage 2 confirm the selective construction of a predetermined sequence of metal centers along with the peptide backbone. The WSMOCA cleaved from the resin at the end of stage 2 has a certain level of solubility in aqueous media dependent on the pH value and/or salt content, which is useful for the purification of the compound.

Synthesis of a Water-soluble Metal&amp;#8211;Organic Complex Array

A potential general method for the synthesis of water-soluble multimetallic peptidic arrays containing a predetermined sequence of metal centers is presented.

We demonstrate a method for the synthesis of a water-soluble multimetallic peptidic array containing a predetermined sequence of metal centers such as ...

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 ...