SYNTHESIS OF ZnO AND ITS PHOTOCATALYTIC ACTIVITY

Abstract

In the present work, mesoporous ZnO are successfully prepared with the help of hydrothermal method and sol gel method. Zinc nitrate hexahydrate, ctab, urea are used as precursor materials. The ZnO powder obtained is calcined at 800 0C and analyzed different properties and behavior of nanoparticles. The method which is used ,has been implicated with some modification with the aim to reduce the size of nanoparticles followed by the paper, and changes are studied with the help of different experimental characterization as XRD conferred ZnO, SEM and TEM revealed different morphology, shape and structure of particles. BET gives pores size and diameter, advantage of lesser size of particles with pores of having large surface area due to which it will take less time to degrade dye which is required and present research need for efficient applications and then determining the photocatalytic degradation of rhodamine-b dye on mesoporous ZnO nanoparticles. Photocatalysis is a well defined approach in which UV light energy is focussed to excite the semiconductor material producing electron/hole pair which eventually involves in the detoxification of pollutants (in water or air) and water splitting. Existing photocatalysts suffer from poor activity or no activity in visible light irradiation which restricts them from solar light utilization. Photocatalytic oxidation processes with ultra violet (UV) radiation and semiconductor photocatalyst like zinc oxide (ZnO) have gained an interest as an effective wastewater purification method because of its efficacy in decomposing and mineralising the hazardous organic pollutants and also utilizing the solar UV and visible spectrum. Rhodamine B is a significant dye. Color is one of the vital characteristics of these effluent streams and seems to be the most undesired, as it affects the nature of water by inhibiting sunlight penetration hence reducing photosynthetic action. Thus, to remove color from industrial effluents is a major concern in wastewater treatment, and treatment is needed before discharging to receiving water. To remove dye pollutants there are various conventional methods such as adsorption on activated carbon, ultra filtration, reverse osmosis, coagulation by chemical agent etc. The pollutants cannot be completely degraded by given methods, the incapability of conventional methods to effectively remove pollutants leads to discover new, efficient and cost effective methods. Photocatalytic process relies on the activation of semiconductor that gives generation of electrons /holes. These holes can react with water to produce hydroxyl radical which results inseries of redox reaction to destroy the pollutants. ZnO has been demonstrated to be an excellent catalyst.