Assembling metal oxide nanoparticles to clays: towards advanced materials for environmental applications Pilar Aranda 1 , Carolina Belver 1,2 , Yorexis González ‐ Alfaro 1 , Margarita Darder 1 , Eduardo Ruiz ‐ Hitzky 1 1 Instituto de Ciencia de Materiales de Madrid, CSIC, Spain 2 Autonomous University of Madrid, Spain 3 rd Japanese ‐ Spanish Bilateral Symposium (SJ ‐ NANO 2013)
Nanoarchitectonics This is a term coined at the National Institute for Materials Science ( NIMS ) 1 in Japan to define the preparation of materials by arranging at the nanoscale structural units using different experimental approaches, such as physical and/or chemical manipulation of atoms and molecules, field ‐ induced manipulation and self ‐ assembly synthetic. These methodologies can be applied to prepare sophisticated materials from very complex precursors but it can be also applied to the preparation of functional materials based on world ‐ spread resources as it is the case of clay minerals: this is the case of heterostructures consisting in assembling clay minerals with other inorganic solid s. 1. http://en.wikipedia.org/wiki/Nanoarchitectonics 11/03/2013 SJ ‐ NANO 2013 2
Nanoarchitectonics 11/03/2013 SJ ‐ NANO 2013 3
Clays 11/03/2013 SJ ‐ NANO 2013 4
Clay minerals: main fields of interest ‐ Soil Science & Agronomy ‐ Adsorbents & Catalysts ‐ Petroleum Industry ‐ Cosmetics ‐ Pharmaceuticals & Bio ‐ Medical ‐ Environment preservation ‐ Civil Engineering ‐ Food: Additives & Packaging ‐ Animal Nutrition ‐ Industrial Specialties ‐ Energy ‐ Advanced Materials 11/03/2013 SJ ‐ NANO 2013 5
Advanced applications of clays 11/03/2013 SJ ‐ NANO 2013 6
Ecomaterials The concept of ecomaterials was created to denominate the ecologically ‐ benign materials , being proposed to encourage the development of materials that are non ‐ damaging to the global environment 11/03/2013 SJ ‐ NANO 2013 7 K. Yagi and K. Halada in EUROPEAN WHITE BOOK Material Science and Engineering, Chap. 6.10
Functional nanostructured clays: clay ‐ NPs Clay ‐ nanoparticle (NP) systems can be used for environmental remediation (water treatment). Examples: ‐ Supported NPs for photo ‐ decomposition of pollutants (e.g., [Ti ‐ NPs] ‐ clays) ‐ Magnetic clays for the adsorption and recovering of pollutants (e.g., [Fe 3 O 4 ‐ NPs] ‐ clays & organoclays) ‐ Hexacyanoferrate supported on magnetic clays for Cs + removal ‐ Superparamagnetic catalysts based on iron ‐ oxide NPs supported on clays for advanced oxidation processes (e.g. Fenton reactions) 11/03/2013 SJ ‐ NANO 2013 8
Layered and fibrous clay minerals ‐ cation ‐ exchange ‐ nanopores ‐ surface Si ‐ OH groups ‐ cation ‐ exchange ‐ swelling properties 11/03/2013 SJ ‐ NANO 2013 9
TiO 2 / & SiO 2 ‐ TiO 2 /clay nanoarchitectures � Metal oxide NPs-clay nanoarchitectures Layered silicates: • montmorillonites • vermiculite P . Aranda, R. Kun, M.A. Martín-Luengo, S. Letaïef, I. Dékány, E. Ruiz-Hitzky, Chem. Mater. 20 (2008) 84-89 E. Manova, P . Aranda, M.A. Martin-Luengo, S. Letaief, E. 11/03/2013 SJ ‐ NANO 2013 10 Ruiz-Hitzky, Micropor. Mesopor. Mater. 131 (2010) 252–260
Assembling of TiO 2 and SiO 2 ‐ TiO 2 NPs SiO 2 -TiO 2 SiO 2 -TiO 2 TiO 2 TiO 2 Assembling to layered clays TiO 2 TiO 2 SiO 2 -TiO 2 SiO 2 -TiO 2 TiO 2 TiO 2 SiO 2 -TiO 2 SiO 2 -TiO 2 TiO 2 TiO 2 SiO 2 -TiO 2 SiO 2 -TiO 2 � the heterostructures show specific surface areas more than 3 times larger than the pristine clay as it became delaminated due to the presence of titania or silica ‐ titania NPs (10 ‐ 15 nm diameter) between the silicate layeres E. Manova, P . Aranda, M.A. Martin-Luengo, S. Letaief, E. Ruiz-Hitzky, Micropor. Mesopor. Mater. 131 (2010) 252–260 Assembling to sepiolite fibrous clay � generation of supported anatase NPs that can act as photocatalysts of high active surface area and easy recovering by filtration. P . Aranda, R. Kun, M.A. Martín-Luengo, S. Letaïef, I. Dékány, E. Ruiz-Hitzky, Chem. Mater. 11/03/2013 SJ ‐ NANO 2013 11 20 84-89 (2008)
TiO 2 / & SiO 2 ‐ TiO 2 /sepolite nanoarchitectures 100 � Stabilization CTAB-sepiolite of sepiolite and 80 anatase phase: clay/TIPO/TMOS = 6/4/5, S-doped 10% TiO 2 -40% SiO 2 -50% clay TiO 2 /sepiolite direct photolysis 60 TOC/TOC 0 (%) S-TiO 2 500 o C/4h 40 clay/TIPO = 1/2, � Main interest in 36 % TiO2 clay/TIPO/TMOS = 2/6/1, 40% TiO 2 -10% SiO 2 -50% clay photocatalysis: e.g., photocatalytic degradation of KUN3-C2 20 KUN6-C2 phenol using different TiO 2 - KUN23 sepiolite heterostructures direct sepiolite clay/TIPO = 1/3, 46 % TiO2 KUN1-C2 S-TiO2 500oC/4h 0 P . Aranda, R. Kun, M.A. Martín-Luengo, S. Letaïef, I. 0 20 40 60 80 100 120 Dékány, E. Ruiz-Hitzky, Chem. Mater . 20 , 84 (2008) irradiation time (min) 11/03/2013 SJ ‐ NANO 2013 12
Supported ferrofluids (“dry ferrofluids”) Multifunctional porous & magnetic materials synthetized by treatment of silica, clays, zeolites, activated carbon.. with ferrofluids (eg., magnetite ‐ oleic acid NPs) 120 100 Accesible at: NP10% 80 NP35% http://www.icmm.csic.es/eng/sciact/Nanos 60 NP20% tructured ‐ Hybrid ‐ Biohybrid ‐ and ‐ Porous ‐ NP50% 40 Materials ‐ Group.htm NP M (emu / g NP ) 20 0 -20 -40 -60 -80 -100 -120 -20000 -15000 -10000 -5000 0 5000 10000 15000 20000 4 H (T)*10 • E. Ruiz-Hitzky, P . Aranda, Y . González-Alfaro, Spain Pat. 201030333 (2010) & PCT ES2011/070145 (2011) • Y . González-Alfaro, P . Aranda, F . M. Fernandes, B. Wicklein, M. Darder, E. Ruiz-Hitzky, Adv. Mater. 23 (2011) 5224–5228 11/03/2013 SJ ‐ NANO 2013 13
Superparamagnetic Fe 3 O 4 ‐ sepiolite adsorbent Adsorption of ionic & molecular pollutants (heavy metals, radionuclides,..) for their easy elimination from aqueous solutions Accesible at: http://www.icmm.csic.es/eng/sciact/Nanos tructured ‐ Hybrid ‐ Biohybrid ‐ and ‐ Porous ‐ Materials ‐ Group.htm • E. Ruiz-Hitzky, P . Aranda, Y . González-Alfaro, Spain Pat. 201030333 (2010) & PCT ES2011/070145 (2011) • Y . González-Alfaro, P . Aranda, F . M. Fernandes, B. Wicklein, M. Darder, E. Ruiz-Hitzky, Adv. Mater. 23 11/03/2013 SJ ‐ NANO 2013 14 (2011) 5224–5228
Specific adsorbent for radioactive Cs removal Several technologies based on Cs ‐ complexing ability of Prusian Blue (hexacyanoferrates of Fe, Cu or Ni (II)) are potentially of interest for removing and collecting radioactive cesium. KFe III [Fe II (CN) 6 ] ∙ yH 2 O (y = 1 ‐ 5) “soluble” Prussian Blue ( hexacyanoferrate, HCF) One of them (JNC Corp) water ‐ soluble ferrocyanide , which works as an adsorbent, is added to cesium ‐ contaminated water so that it is bonded with cesium . Then, the resultant material is reacted by using iron chloride, which is a material for “magnetic substance” ( sic ). When an alkaline solution is added to it, a magnetic material containing cesium is generated . By using a magnet for magnetic separation, cesium can be removed and collected from the contaminated water. 11/03/2013 SJ ‐ NANO 2013 15 http://techon.nikkeibp.co.jp/english/NEWS_EN/20111227/203092/
Magnetic sorbent for radioactive Cs removal Amount of adsorbed Cs + by sepiolite ‐ magnetite ‐ HCF based materials Sample mmoles/g References SepNP50P ‐ Fe HCF 0.23 This work* SepNP50P ‐ Cu HCF 0.36 This work* Latex NPs/HCFs 0.02 – Avramenko et al. J. Hazard. Mater. 0.04 2011, 186, 1343 ‐ 1350 Activated C/CuHCF 0.38 Li et al., Sep. Sci. Technol . 2009, 44, 4023 ‐ 4035 Magnetite/HCFs 0.12 Sasaki et al., Chem Lett. 2012, 41, 32 ‐ 34 * Cs removal capacity: 30 ‐ 50 g ‐ Cs/kg ‐ magnetic clay adsorbent CONCLUSION : The preliminary results at the laboratory level expect that the procedure here reported was satisfactorily applicable for the removal of radioactive Cs + by magnet from water contaminated, even in the presence of NaCl (e.g., 0.3 M). 11/03/2013 SJ ‐ NANO 2013 16 E. Ruiz-Hitzky, P . Aranda, M. Darder, Y . González-Alfaro, Spanish Patent P201330062 (2013)
Conclusions •Clays are abundant and versatile eco ‐ materials that can be assembled at the nanometric scale to metal oxide nanoparticles, leading to advanced functional materials relevant for applications in environmental remediation •Assembling of metal oxide NPs and clays can be reached using ferrofluids in which are incorporated the NPs or via a colloidal route that use organoclays and sol ‐ gel methodologies • Environmental applications of the resulting NPs ‐ clay nano ‐ architectures include their use as photocatalysts and superparamagnetic adsorbents (e.g. in elimination of radioactive cesium) & catalysts (e.g. in catalytic wet peroxide oxidation process of organic pollutants) 11/03/2013 SJ ‐ NANO 2013 17
Acknowledgements Financial support: � CICYT (MAT2009 ‐ 09960 & MAT2012 ‐ 31759 projects) � Ramón y Cajal Program (Dr. C. Belver contract) Technical assistance: � Mr. Andrés Valera – FE ‐ SEM 11/03/2013 SJ ‐ NANO 2013 18
Thank you very much for your attention!! 11/03/2013 SJ ‐ NANO 2013 19
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