Efficient UV-light photocatalytic activity of TiO2@Phosphogypsum composite synthesized by sol–gel method

There is no doubt that novel and efficient photocatalyst with excellent properties based on TiO2 are highly desirable for practical applications to degrade high-concentration pollutants. Until now TiO2 nanoparticles have been successfully coupled with phosphogypsum prepared via a simple sol–gel method after calcination at different temperatures. The efficiency of the photocatalytic activity of composite can be explained by the difference of calcination temperatures in the structure of TiO2. Structures, morphologies, and surface areas were examined in all samples using specific characterization methods. In this process, the anatase and rutile structure of TiO2 nanoparticles were determined. The results obtained showed that the forms of the composite are spherical, although some nanoparticles are agglomerated. Surface area analyses showed that higher surface areas were obtained when the composite calcinated at 450 °C. We can attribute this to the small size of the particles. This study demonstrates that the synthesized composite display excellent photo-activity for degrading nitrate from aqueous solution up to 93.5% after 180 min of UV light irradiation time. Hence, we demonstrate a simple and efficient method to valorize phosphogypsum and to prepare a promising composite photocatalyst for reduction of nitrate in water and wastewater treatment process.