Investigating the extrusion of alumina silicate pastes for synthesis of monolith zeolite A

Download

index.pdf

Date

2005

Author

Özcan, Ayşenur

Metadata

Show full item record

Item Usage Stats

133
views

194
downloads

Zeolites are highly porous materials that are most commonly used in granular or beaded forms. In general, zeolite granules, beads or monoliths are manufactured by using an inorganic binder which helps to cement zeolite crystals together. However, this inorganic binder decreases the purity of the zeolite structures and accessibility to the zeolite pores. A new and relatively easy method was offered for the production of binderless zeolite A tubes and bars from amorphous alumina silicate extrudates in this study. Amorphous alumina silicate powder, which is obtained by filtering the homogenous hydrogel with a composition of 2.5Na2O:1Al2O3:1.7SiO2:150H2O, is mixed with an organic binder (HEC-Hydroxyethyl Cellulose) to obtain the paste. The paste is then extruded through a die of a home-made extruder into bars and tubes. These extrudates were dried at room temperature for 24 hours, then calcined at 600oC for 2 hours and finally synthesized at 80oC for 72 hours in hydrothermal conditions to convert amorphous alumina silicate to zeolite. The most appropriate amorphous alumina silicate powder (A) / 4wt% HEC solution (H) ratio to prepare paste, hence to prepare bars and tubes was found as 0.82. The crystallinity of bars and tubes was 91% and 97%, respectively, and zeolite A was the only crystalline material. The bars and tubes were composed of highly intergrown zeolite A crystals with high porosity. Porosity of the bars is approximately 39% and porosity of the tubes is 29%, with a narrow pore size distribution. Bars have macropores of 2 æm, while the macropores of the tubes are 3-4 æm. The BET surface area of the bars was 411 m2/g and of tubes was 439 m2/g, which are comparable with the commercial zeolite A beads. Bars had a crushing strength of 0.42 MPa, which is sufficiently high to handle. In conclusion, zeolite A bars and tubes, with their high purity, macroporous

Subject Keywords

Crystallography.

URI

http://etd.lib.metu.edu.tr/upload/2/12606469/index.pdf
https://hdl.handle.net/11511/15373

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Synthesis of uniformly distributed single- and double-sided zinc oxide (ZnO) nanocombs Yıldırım, Özlem Altıntaş; Liu, Yuzi; Petford-Long, Amanda K. (Elsevier BV, 2015-11-15) Uniformly distributed single- and double-sided zinc oxide (ZnO) nanocomb structures have been prepared by a vapor-liquid-solid technique from a mixture of ZnO nanoparticles and graphene nanoplatelets. The ZnO seed nanoparticles were synthesized via a simple precipitation method. The structure of the ZnO nanocombs could easily be controlled by tuning the carrier-gas flow rate during growth. Higher flow rate resulted in the formation of uniformly-distributed single-sided comb structures with nanonail-shaped t...
Modelling of Diffusion in Random Packings of Core-Shell Particles Hatipoğlu, Emre; Koku, Harun (Hacettepe University, 2017-04-01) Core-Shell particles are commonly used materials in chromatography. In this study, a mathematical model that mimics diffusion around Core-Shell particles was developed. A random-walk based algorithm was implemented to simulate diffusion and a Core-Shell particle geometry was computationally formed, based on simple geometric constructs and relations. Diffusion simulations were carried out on a randomly packed geometry formed from these particles. The behavior of time-dependent diffusivity data obtained from ...
Investigation of gmpls applications in optical systems Göken, Burcu; Ergül, Rüyal; Department of Electrical and Electronics Engineering (2005) In this study, possible applications of label switching in large area, fully optical networks are investigated. The objective was to design a label assignment method by using Generalized Multi-Protocol Label Switching (GMPLS) concept to get an efficient optical network operation. In order to fulfill this objective, two new approaches were proposed: a label assignment method and a concatenated label structure. Label assignment method was designed to provide an efficient utilization of resources. Concatenated...
Studies on visual detection and surface modification testing of glass microfiber filter paper based biosensor Adiguzel, Yekbun; Külah, Haluk (Elsevier BV, 2014-04-15) Glass microfibers are commonly used as biomolecule adsorption media, as structural or disposable components of the optical biosensors. While any improvement in these components are appreciated, utilizing basic tools of traditional approaches may lead to original sensor opportunities as simple, functional designs that can be easily disseminated. Following this pursuit, surface modification of glass microfiber paper surface was performed by 3-aminopropyltriethoxysilane (APTES) and resulting improvement in the...
The formation of smooth, defect-free, stoichiometric silicon carbide films from a polymeric precursor Pitcher, Michael; Bianconi, Patricia (2006-04-20) Silicon carbide (SiC) materials, which are used in a variety of applications, are often produced using powder processing, sintering or bulk crystal growing techniques. The formation of silicon carbide films or shaped products, via these methods, is often extremely difficult and/or requires high temperatures. Here we report the synthesis and characterization of a polymeric precursor, Polymethylsilyne (PMSy), and it subsequent conversion to beta-SiC. The polymer is simple to synthesize and is easily manipulat...

Citation Formats

A. Özcan, “Investigating the extrusion of alumina silicate pastes for synthesis of monolith zeolite A,” M.S. - Master of Science, Middle East Technical University, 2005.