APCATB 125-2012-311

Isomorphous substitution of Zr in the framework of aluminosilicate HY by an
electrochemical method: Evaluation by methylene blue decolorization

Isomorphous substitution of Zr in the framework of aluminosilicate HY occurred during the preparation
of electrogenerated zirconia supported HY (EGZrO2/HY) catalyst via a simple electrochemical method.
Dealumination accompanied by an ion exchange with Zr4+ formed Si O Zr bond, which controlled the
formation of active species EGZrO2 that influenced the efficiency of the photodecolorization of methylene
blue (MB). An amount of 0.375 g L−1 1 wt% EGZrO2/HY was found to be the optimum dosage for 10 mg L−1
MB, which resulted in 97% decolorization after 6 h of contact time at pH 11. The kinetics study indicates
that the reaction follows the Langmuir–Hinshelwood model, where the reaction may occur both on the
surface of the catalyst and in the bulk solution. The mineralization of MB was measured by removal
of chemical oxygen demand (COD), five days biochemical oxygen demand/chemical oxygen demand
(BOD5/COD), and total organic carbon (TOC/TOC0), and the results obtained were 95%, 7.14, and 0.08,
respectively. After five cycling runs, the catalyst was still stable and showed no leaching effect. This study
is believed to be extendable to the synthesis of other catalysts with different characteristics and be used
in various applications.