Isomorphous substitution of ZR in the framework of aluminosilicate hy by an electrochemical method: evaluation by methylene blue decolorization

Abstract

Isomorphous substitution of Zr in the framework of aluminosilicate HY occurred during the preparation of electrogenerated zirconia supported HY (EGZrO 2/HY) catalyst via a simple electrochemical method. Dealumination accompanied by an ion exchange with Zr 4+ formed SiOZr bond, which controlled the formation of active species EGZrO 2 that influenced the efficiency of the photodecolorization of methylene blue (MB). An amount of 0.375gL -1 1wt% EGZrO 2/HY was found to be the optimum dosage for 10mgL -1 MB, which resulted in 97% decolorization after 6h 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 (BOD 5/COD), and total organic carbon (TOC/TOC 0), 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.