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.

中文翻译：

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溶胶-凝胶法合成的TiO2@磷石膏复合材料的高效紫外光催化活性

毫无疑问，具有优异性能的基于 TiO2 的新型高效光催化剂对于降解高浓度污染物的实际应用是非常理想的。到目前为止，TiO2 纳米颗粒已经成功地与通过简单的溶胶-凝胶法在不同温度下煅烧后制备的磷石膏偶联。复合材料光催化活性的效率可以用二氧化钛结构中煅烧温度的差异来解释。使用特定的表征方法检查了所有样品的结构、形态和表面积。在此过程中，确定了 TiO2 纳米颗粒的锐钛矿和金红石结构。获得的结果表明复合材料的形式是球形的，尽管一些纳米颗粒是团聚的。表面积分析表明，当复合材料在 450 °C 下煅烧时，获得了更高的表面积。我们可以将其归因于粒子的小尺寸。该研究表明，合成的复合材料在紫外线照射 180 分钟后显示出优异的光活性，可将水溶液中的硝酸盐降解至 93.5%。因此，我们展示了一种简单有效的方法来使磷石膏增值并制备一种有前途的复合光催化剂，用于还原水和废水处理过程中的硝酸盐。180 分钟紫外线照射时间后 5%。因此，我们展示了一种简单有效的方法来使磷石膏增值并制备一种有前途的复合光催化剂，用于还原水和废水处理过程中的硝酸盐。180 分钟紫外线照射时间后 5%。因此，我们展示了一种简单有效的方法来使磷石膏增值并制备一种有前途的复合光催化剂，用于还原水和废水处理过程中的硝酸盐。