(544dx) Influence of Salt on Nanozeolite-Y Particles Size Synthesized Under Organic Template Free Condition

Influence of salt on Nanozeolite-Y particles
size synthesized under organic template free Condition

Hanin M. Radman^a,b, Aasif A. Dabbawala^a,
Yasser F. Alwahedi^a,
Gnana P. Singaravel^b,
Stephane Morin^b, Mikael Berthod^b and Saeed M. Alhassan^a*

^a Materials and catalysis division, Chemical
engineering department, Khalifa University of Science and Technology, Abu
Dhabi, UAE

^b Catalysis division, ADNOC refining research
center, Abu Dhabi, UAE

Corresponding E-mail: saeed.alkhazraji@ku.ac.ae

ABSTRACT

Zeolites (crystalline
aluminosilicate) having 3D channel network are widely used by the chemical
industry. Faujasite Y in particular is one of preferred micro-sized zeolite to
be utilized as acid catalyst for catalytic cracking process. Considering the important
applications of zeolite-Y, current research is directed to modify its surface properties and
catalytic performance. Synthesis of zeolite-Y in nano-size is one
approach to overcome
shortcomings in the micro-sized zeolite-Y. However, the preparation of nanozeolite
still remains a challenging task which requires either tertiary amine based organic
template or higher amount of NaOH to control the size. On the other hand a
template free methodology has many advantages in which sodium cations can solely
act as structure directing agent. Nevertheless, the increase of alkalinity may lead
to re-dissolution of growing crystals and reduce Si/Al ratio. Herein, we present
synthesis of nanozeolite with optimum amount of NaOH and by balancing Na
content using inorganic salt. Surprisingly, the addition of alkali metal salt as
secondary source for Na⁺ alters zeolite-Y particle size without
reducing Si/Al ratio. Depending on the method used (clear or dense-gel), the
growth of nano-size crystals was affected by the amount of salt added during
synthesis (Scheme 1).
In clear-solution (CS) method, the increase of salt content led to a decrease in
crystal size from 165 to 110 nm. In contrast, in dense -gel (DG) method, the crystal size is found to increase from
140 to 250 nm.

Scheme 1: Influence
of salt on synthesis of nano-size zeolite-Y by template free method.