Synthesis of binderless tubular Zeolite X macrobodies

Download

index.pdf

Date

2010

Author

Gürtepe, İrde Çetintürk

Metadata

Show full item record

Item Usage Stats

135
views

340
downloads

Zeolites are microporous crystallines with well defined structures. Zeolites are used in variety of applications because of their properties such as high temperature stability, ion-exchange capacity, adsorption capacity and stability to harsh conditions. Some major applications of zeolites are ion-exchange, catalysis, adsorption and separation. Synthetic zeolites are normally produced as fine crystalline powder. Prior to their use, the powder is usually formed into spheres, tablets and extrudates by addition binder. Since binders present in the zeolite can block the pores and decrase the adsorption properties, preparation binderless zeolite agglomerates with high mechanical stability has great technological importance. Objective of the study is to synthesize binderless zeolite X tubular macrobodies by using the developed methods for the synthesis of zeolite A bars and tubes. Main steps of the study are synthesis of the tubular binderless zeolite X macrobodies, characterization of the macrobodies, determination the effect of hydrogel composition on zeolite phase and analyzing effect of time on the crystallinity of macrobodies. Experimental method for synthesizing the binderless tubular zeolite X macrobodies includes the following steps; preparing hydrogel by mixing sodium aluminate and sodium silicate solutions, filtration of the hydrogel, paste preparation from solid phase of the hydrogel, extrusion of green tubes from paste, calcination of green tubes and crystallization of calcined tubes in filtered liquid of the hydrogel. In this study, synthesis of binderless tubular pure zeolite X macrobodies with high crystallinity was achieved. Micropore volume and BET surface area of the zeolite X tubular macrobody İÇS-18, which has 99.9 % crystallinity were determined as 0.178 cm3/g and 631.2 m2/g, respectively. Pure zeolite X, pure zeolite A and zeolite A, X mixtures were obtained after the crystallization of the calcined extrudates which were obtained from different hydrogel compositions. Ternary diagram which was based on the hydrogel compositions and the obtained zeolite phases was plotted.

Subject Keywords

Zeolites.

URI

http://etd.lib.metu.edu.tr/upload/12612789/index.pdf
https://hdl.handle.net/11511/20261

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

The Influence of some embedding properties of subgroups on the structure of a finite group Kızmaz, Muhammet Yasir; Ercan, Gülin; Department of Mathematics (2018) In a finite group $G$, a subgroup $H$ is called a $TI$-subgroup if $H$ intersects trivially with distinct conjugates of itself. Suppose that $H$ is a Hall $pi$-subgroup of $G$ which is also a $TI$-subgroup. A famous theorem of Frobenius states that $G$ has a normal $pi$-complement whenever $H$ is self normalizing. In this case, $H$ is called a Frobenius complement and $G$ is said to be a Frobenius group. A first main result in this thesis is the following generalization of Frobenius' Theorem. textbf{Theorem...
Multicomponent ion exchange on synthetic zeolites Beşel Düzgün, Elif; Yücel, Hayrettin; Department of Chemical Engineering (2014) Zeolites are natural and synthetic microporous crystalline aluminosilicates with ion-exchange and molecular sieve properties. Zeolites consist of a three-dimensional framework of (SiO4)4- and (AlO4)5- tetrahedras, connected by a shared oxygen atom. The presence of aluminum in the aluminosilicate framework introduces a net negative charge. Zeolites are mostly used in ion exchange, adsorption processes and catalytic applications. The objective of the study was to determine and model the multicomponent ion exc...
Perfect discrete morse functions on connected sums Varlı, Hanife; Pamuk, Mehmetcik; Kosta, Neza Mramor; Department of Mathematics (2017) Let $K$ be a finite, regular cell complex and $f$ be a real valued function on $K$. Then $f$ is called a textit{discrete Morse function} if for all $p$-cell $sigma in K$, the following conditions hold: begin{align*} displaystyle n_{1}=# {tau > sigma mid f(tau)leq f(sigma)} leq 1, \ n_{2}=# {nu < sigma mid f(nu)geq f(sigma)}leq 1. end{align*} A $p$-cell $sigma$ is called a textit{critical $p$-cell} if $n_{1}=n_{2}=0$. A discrete Morse function $f$ is called a textit{perfect discrete Morse function} if the nu...
Scherk-Schwarz reduction of effective string theories in even dimensions Özer (Çatal), Aybike; Karasu, Emine Ayşe; Department of Physics (2003) Scherk-Schwarz reductions are a generalization of Kaluza-Klein reductions in which the higher dimensional fields are allowed to have a dependence on the compactiifed coordinates. This is possible only if the higher dimensional theory has a global symmetry and the dependence is dictated by this symmetry. In this thesis we consider generalised Scherk Schwarz reductions of supergravity and superstring theories with twists by electromagnetic dualities that are symmetries of the equations of motion but not of th...
Divisibility properties on boolean functions using the numerical normal form Göloğlu, Faruk; Yücel, Melek D; Department of Cryptography (2004) A Boolean function can be represented in several different forms. These different representation have advantages and disadvantages of their own. The Algebraic Normal Form, truth table, and Walsh spectrum representations are widely studied in literature. In 1999, Claude Carlet and Phillippe Guillot introduced the Numerical Normal Form. NumericalNormal Form(NNF) of a Boolean function is similar to Algebraic Normal Form, with integer coefficients instead of coefficients from the two element field. Using NNF re...

Citation Formats

İ. Ç. Gürtepe, “Synthesis of binderless tubular Zeolite X macrobodies,” M.S. - Master of Science, Middle East Technical University, 2010.