Characterization of La/Fe/TiO2 and Its Photocatalytic Performance in Ammonia Nitrogen Wastewater

La/Fe/TiO2 composite photocatalysts were synthesized by Sol-Gel method and well characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen-physical adsorption, and UV-Vis diffuse reflectance spectra (UV-Vis DRS). It is interesting that the doped catalysts were in anatase phase while the pure TiO2 was in rutile phase. In addition, the composites possessed better physical chemical properties in photocatalytic activity than pure TiO2: stronger visible-light-response ability, larger specific surface area, and more regular shape in morphology. The photodegradation results of ammonia nitrogen indicate that: the La/Fe/TiO2 had higher catalytic activity to ammonia nitrogen waste water compared pure TiO2 and the other single metal-doped TiO2. pH 10 and 2 mmol/L H2O2 were all beneficial to the removal of ammonia nitrogen by La/Fe/TiO2. However, the common inorganic ions of Cl-, NO3-, SO42-, HCO3-/CO32-, Na+, K+, Ca2+ and Mg2+ in water all inhibited the degradation of ammonia nitrogen. By balance calculation, at least 20% of ammonia nitrogen was converted to N-2 during the 64.6% removal efficiency of ammonia nitrogen.