Total Oxidation of Isopropanol in Liquid Phase, Under Atmospheric Pressure and at Low Temperature on a Stable and Inexpensive Catalyst Based on Nickel Oxide Prepared

This work aims to check the catalytic efficiency of nickel oxide within the complete coldness liquid phase oxidation of isopropanol. Our interest has been focused on isopropanol since it was classified as a volatile organic compound that causes environmental pollution. Total catalytic oxidation of toxic and carcinogenic isopropanol (IPA), widely used as a solvent and cleaning fluid, is still one of the most recognized low-cost and efficient techniques to remediate indoor environmental pollutants. Our Study aims to design a low-cost, high, and stable nickel oxide-based catalyst for the total oxidation of IPA into organic compounds of carbon dioxide and water under conditions close to those of a typical environment. In the first step, the preparation and characterization of by various physicochemical methods of Nickel oxide have been done. Nickel oxide has been crystallized in a face-centered cubic structure with an average grain size of 35.5 nm. FTIR analysis confirmed the XRD results by exhibiting well-defined peaks related to Ni-O bonds, indicating the high quality of the synthesized samples. Textural properties show the good texture of NiO-based-catalyst with a specific surface area of 3 m 2 /g, an average pore diameter of 189 Å, and a pore volume of 0. 09 cm 3 /g. The DTG/DTA investigations showed the resistance of nickel oxide to the thermal treatment with a measured weight loss of 1.761% that could be assigned to the dehydration of the sample and a second weight loss related to the loss of carbon dioxide. Scanning electron microscopy shows that the NiO nanoparticles consist of irregularly shaped grains interconnected with each other. Nickel oxide prepared by the precipitation method shows good catalytic activity towards the decomposition of the toxic isopropanol in its liquid phase at low temperatures with a destruction duration of isopropanol not exceeding 2 h whatever the temperature with the formation of acetone as a secondary by product. Acetone could be formed in an oxidizing environment by oxidative hydrogenation. In this case, the active site would be a pair of redox sites. Moreover, the kinetic study of the isopropanol oxidation reaction, in a liquid phase, showed that this reaction follows a successive mechanism from isopropanol to acetone. The apparent activation energy of nickel oxide was determined to be 4.56 KJ.mol − 1 . This low value explains the relatively high catalytic activity of NiO-based catalysts. It is clear that the low weight of the apparent energy of activation is related to the high values of the catalytic activity of nickel oxide.