Preparation And Investigation Of BiVO₄ Loaded On Semi-coke And Photocatalytic Removal Of NO

NOx as one of the major sources of air contaminations, can not only cause photochemistry smog, but do harm to our health. Photocatalytic removal of NOx is an environmentally friendly technology and it has made considerable progress. The development of visible light photocatalyst which can raise light energy utilization ratio attracted more and more attention. In this paper, we focus on the addition of BiV04 in the catalyst system based on the prior research of our lab.In this paper, BiVO4/ASC as photocatalyst was prepared by hydrothermal synthesis method, using Bi(NO3)3·5H2O as source of bismuth, NH4VO3 as source of vanadium and activated semi-coke as carrier. The synthesized photocatalyst is characterized by BET、XRD、SEM、UV-Vis and FT-IR. The results show that the prepared BiVO4 is monoclinic crystal phase and the surface profile is fiber rod. BiVO4 prepared on the surface of activated semi-coke can produce energy level effect with carbon atom which lead to the reduction of the band gap.The synthesized photocatalyst was evaluated by the removal of NOx. The effect of loading of active component, hydrothermal reaction temperature,and hydrothermal reaction time was studied. The results show that after 4h reaction at 160℃,the loading amount of BiVO4 is 1.5%wt, and BiVO4/ASC was calcined at 400℃, NOx reduction efficiency is above 80%. The effect of reaction temperature, oxygen and water vapor content are also investigated. The results show that the catalytic activity of BiVO4/ASC is consistently decreasing, this is because the active functional group on the semi-coke surface is eroded by HNO3 which is produce during the reaction. The optimum reaction conditions are as follows:at 100℃, the oxygen content is 5%, the water vapor content is 5-8%, the air velocity is 1000h-1.Regeneration treatment of the photocatalyst is conducted by thermal regeneration, hydrothermal regeneration and ammonia regeneration. The results show that after 5 times with ammonia regeneration, the NOx reduction efficiency of the photocatalyst is still above 60% in four hours.