A case study on the understanding of the formation of hierarchical Beta zeolites using gemini-type piperidine based multiammonium surfactant (N-6-diphe) is reported. Complementary techniques were used to investigate N-6-diphe's structure-directing effect at the molecular level. Combining characterization of the resulting zeolite materials with the toolboxes herein developed for studying clear solutions and dense gels discloses self-assembly processes that govern the growth (and growth inhibition) of nano-Beta zeolite crystals. In clear solution, small-angle X-ray scattering and liquid-state NMR provide insights about the formation of nanoparticles and their degree of order. N-14 and H-1-DOSY NMR probe the dynamics and mobility of soluble species. In a dense gel, on the other side, Al-27- and Si-29-(MAS) NMR elucidate the varying local connectivity between initial nano-objects and the final solid products. It has been found that cylindrical micelles control the transformation of solubilized silica and alumina during the formation of zeolite nuclei and guide their crystal growth to nano-Beta rods with bimodal mesoporosity. The predominant smaller mesopores (6 to 8 nm) originate from the template's hydrophobic alkyl chains, while larger mesopores (10 to 30 nm) are supposed to result from a spinodal decomposition-type segregation of phases consisting of as-formed hydrophobic zeolite rods and an aqueous solution.

Electrochemical impedance spectroscopy (EIS) was used to detect and investigate nucleation in silicalite-1 clear solutions. Although zeolite nucleation was previously assumed to be a step event, inducing a sharp discontinuity around a Si/OH- ratio of 1, complex bulk conductivity measurements at elevated temperatures reveal a gradual decay of conductivity with increased silicon concentrations. Inverse Laplace transformation of the complex conductivity allows the observation of the chemical exchange phenomena governing nanoaggregate formation. At low temperatures, the fast exchange between dissociated ions and ion pairs leads to a gradual decay of conductivity with an increasing silicon content. Upon heating, the exchange rate is slower and the residence time of ion pairs inside of the nanoaggregates is increasing, facilitating the crystallization process. This results in a bilinear chemical exchange and gives rise to the discontinuity at the Si/OH- ratio of 1, as observed by Fedeyko et al. EIS allows the observation of slow chemical exchange processes occurring in zeolite precursors. Until now, such processes could be observed only using techniques such as nuclear magnetic or electron paramagnetic resonance spectroscopy. In addition, EIS enables the quantification of interfacial processes via the double layer (DL) capacitance. The electrical DL thickness, derived from the DL capacitance, shows a similar gradual decay and confirms that the onset of nanoaggregate formation is indeed not narrowly defined.

logo search. British Zeolite Association 2017 Annual Meeting, Date: 2017/04/10 - 2017/04/12, Location: Preston, UK. Publication date: 2017-04. Study of Zeolite Precursors by Electrochemical Impedance Spectroscopy. Author: Brabants, Gert. Breynaert, Eric ; Reichel, Erwin ; Jakoby, Bernhard ; Taulelle, Francis ; Martens, Johan ; Kirschhock, Christine …

Self-supported oligo-layered ZnAlEu LDH nanotubes (∅ 20 nm) self-assemble upon controlled hydrolysis of the metal ions (Zn2+, Al3+, Eu3+) in the presence of 1,3,5-benzenetricarboxylate anions and non-ionic worm-like micelles. Their high surface area and easily accessible cylindrical mesopores (175 m2 g-1; 0.75 cm3 g-1) facilitate interaction with 5 nm CdTe quantum dots, enhancing the overall luminescence behavior.

logo search. 30 Years Prodex, Date: 2016/09/05 - 2016/09/06, Location: European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands. Publication date: 2016-09. In situ monitoring of Zeolite Formation in Zero Gravity. Author: Brabants, Gert. Reichel, Erwin ; Jakoby, Bernhard ; Kirschhock, Christine …

logo search. International Zeolite Conference, Date: 2016/06/19 - 2016/06/24, Location: Rio de Janeiro. Publication date: 2016-06. Quantifying Double Layer Effects in Early Zeolite Formation by Electrochemical Impedance Spectroscopy. Author: Brabants, Gert. Reichel, Erwin ; Taulelle, Francis ; Martens, Johan ; Jakoby, Bernhard ; Kirschhock, Christine …

Hitherto zeolite formation has not been fully understood. Although electrochemical impedance spectroscopy has proven to be a versatile tool for characterizing ionic solutions, it was never used for monitoring zeolite growth. We show here that EIS can quantitatively monitor zeolite formation, especially during crucial early steps where other methods fall short.

We present a pressure-wave-based acoustic sensor device for inline monitoring of polymer flow behavior. The device is made to be integrated in a slit capillary of an in-line-extrusion-rheometer, but could be implemented in any die used for extrusion. It was manufactured to withstand the high pressures involved in the extrusion process by employing a boundary reflection based acoustic measurement to determine the viscosity of the polymer. A high temperature graded PZT disc transducer was used and the whole system was designed to measure viscosities at the temperatures of the extruder without the need for external cooling of the PZT element.

360 Multidiagnostic Analysis to Track Zeolite Formation M. CASTRO1*, M. HAOUAS2, F. TAULELLE2, I. LIM1, E. BREYNAERT3, G. BRABANTS3, C. E. A. KIRSCHHOCK3 AND W. SCHMIDT1 1Max-Plank-Institut fur Kohlenforschung, Mulheim a.d. Ruhr, Germany, (*correspondence: castro@kofo.mpg.de) 2Institut Lavoisier de Versailles, University of Versailles, France 3Center for Surface Chemistry and Catalysis, KU Leuven, Belgium

The unique physical and chemical properties of nanomaterials have led to their increased use in many industrial applications, including as a paint additive. For example, titanium dioxide (TiO2) engineered nanoparticles (ENPs) have well-established anti-UV, self-cleaning, and air purification effects. Silver (Ag) ENPs are renowned for their anti-microbial capabilities and silicon dioxide (SiO2) ENPs are used as fire retardants and anti-scratch coatings. In this study, the toxic effects and biodistribution of three pristine ENPs (TiO2, Ag, and SiO2), three aged paints containing ENPs (TiO2, Ag, and SiO2) along with control paints without ENPs were compared. BALB/c mice were oropharyngeally aspirated with ENPs or paint particles (20 μg/aspiration) once a week for 5 weeks and sacrificed either 2 or 28 days post final aspiration treatment. A bronchoalveolar lavage was performed and systemic blood toxicity was evaluated to ascertain cell counts, induction of inflammatory cytokines, and key blood parameters. In addition, the lung, liver, kidney, spleen, and heart were harvested and metal concentrations were determined. Exposure to pristine ENPs caused subtle effects in the lungs and negligible alterations in the blood. The most pronounced toxic effects were observed after Ag ENPs exposure; an increased neutrophil count and a twofold increase in pro-inflammatory cytokine secretion (keratinocyte chemoattractant (KC) and interleukin-1ß (IL-1ß)) were identified. The paint containing TiO2 ENPs did not modify macrophage and neutrophil counts, but mildly induced KC and IL-1ß. The paints containing Ag or SiO2 did not show significant toxicity. Biodistribution experiments showed distribution of Ag and Si outside the lung after aspiration to respectively pristine Ag or SiO2 ENPs. In conclusion, we demonstrated that even though direct exposure to ENPs induced some toxic effects, once they were embedded in a complex paint matrix little to no adverse toxicological effects were identified.

The formation of zeolites in presence of tetraalkylammonium cations from so-called clear solutions using silicon alkoxides is a highly complex process which challenges experimental chemistry. Most clear solutions are better described as clear sols as they contain nanosized silicate particles, which are formed during hydrolysis of the Si source before self-assembly into the zeolite framework. This process spans multiple time- and length-scales and only a combination of different analysis methods allows revelation of molecular level zeolite formation mechanisms. On the example of the early stages of the formation of zeolite beta from clear solutions/sols the different windows of observation of liquid-state Si-29 and Al-22 nuclear magnetic resonance (NMR) spectroscopy, small angle X-ray scattering (SAXS), dynamic light scattering (DLS) and mass spectrometry (MS) are demonstrated. Each diagnostic means by itself needs to be carefully assessed for its window of temporal and spatial resolution which can be achieved by exploiting the overlapping information available from their combination. (C) 2013 Elsevier Inc. All rights reserved.