سید ناصر عزیزی

In this work, a free template method is used to synthesize nanostructured analcime (ANA) zeolite from natural source and the prepared zeolite is applied as substrate to fabricate a modified electrode. To this aim, ANA zeolite nanoparticles are synthesized by hydrothermal method using amorphous silica extracted from stem of sorghum ash (SSA) with approximately 92.34% purity in the absence of organic template. The effects of different parameters such as Si/Al ratio, heating time, temperature and stirring time on synthesis and crystallinity of zeolite are optimized. The synthesized zeolite is characterized using Xray diffraction, Fourier-transform infrared and scanning electron microscopy (SEM) techniques. SEM shows that ANA zeolite nanoparticles appear as spherical particles contains some smaller nanoparticles which arranged in regular pattern to each other. Also, some fibers consist of nanoparticles in range of 30e48 nm are observed. The modified carbon paste electrode (CPE) is prepared based on ANA modified with Ni species (Ni/ANACPE). The electrochemical oxidation of formaldehyde is studied at Ni/ ANACPE in alkaline solution. From cyclic voltammetry studies, it is shown that Ni/ANACPE can facilitate the oxidation of formaldehyde compared to CPE. The effects of some parameters such as scan rate of potential, concentration of formaldehyde, amount of Nizeolite are investigated on the oxidation of formaldehyde. Also using chronoamperometry technique, the catalytic rate constant (k) for oxidation of formaldehyde is found to be 7.56
104 cm3 mol1 s1.