In-situ synthesis of ZnSe nanoparticles onto monoclinic BiVO4 for boosted photocatalytic decomposition of ammonia nitrogen in water

As excessive ammonia nitrogen in water will result in water eutrophication and damage human health ultimately, efficient approaches to eliminate ammonia nitrogen pollutants in water were in urgent need. Photocatalysis exhibited great advantages in ammonia nitrogen removal such as flexible application, small footprint and no secondary pollution. Herein, one kind of promising ZnSe/BiVO4 composite was prepared by depositing ZnSe nanoparticles onto monoclinic BiVO4 and applied in eliminating ammonia nitrogen pollutants. ZnSe/BiVO4 composites displayed boosted performance in ammonia nitrogen removal than raw BiVO4 and ZnSe due to improved light absorption capability and better charge separation ability. Optimally, 97.6 % of the initial ammonia nitrogen was removed and 95.46 % of the removed ammonia nitrogen was converted to harmless N2 at pH of 10.0 in 120 min over 40 %-ZBVO with initial ammonia nitrogen as 30 mgN/L. Moreover, effects of photocatalyst composition, initial solution pH and impurity ions were investigated. Contributions of stripping, adsorption, photolysis and photocatalysis were clarified. The transfer paths of photogenerated carriers and mechanism of ammonia nitrogen removal were proposed and validated.