With modified diatomite as support

the composite materials of nanoscale zero-valent iron and modified diatomite (NZVI-CDt) were prepared by using sodium borohydride as reducing agent via the liquid phase reduction method. The NZVI-CDt was characterized by X-ray diffraction (XRD)

scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The influences of initial concentrations of nitrate nitrogen (5-30 mg·L-1) and pH (3

5

7 and 9) on removal of nitrate nitrogen were investigated

and the final degradation products were detected. The results showed that the iron nanoparticles were highly dispersed on the surface of diatomite and several iron nanoparticles were embedded within the diatomite porous. Iron nanoparticles had a nearly spherical shape with the range of 100 nm. The NZVI-CDt showed efficient removal of nitrate nitrogen. The removal efficiency could reach 90.1% after 60 min at proper conditions:pH 7

initial 20 mg·L-1 concentration of nitrate nitrogen and 0.5141 g NZVI-CDt at the room temperature. Kinetic studies showed that the reduction of nitrate nitrogen by NZVI-CDt followed the pseudo-first-order kinetics. In addition

kobs decreased with increasing nitrate nitrogen concentration.