Hydrothermal synthesis of V2O5 nanospheres as catalyst for hydrogen sulfide removal from sour water

Abstract

Vanadium pentoxide (V2O5) nanospheres were synthesized hydrothermally for the first time with high specific surface area. The effect of different parameters including pH level, H2O2/H2O volume ratio and reaction temperature on the precipitate yield was investigated, and the highest yield was attained at the pH level of 3, H2O2/H2O volume ratio of 0.01 and the reaction temperature of 160 °C. Freeze drying, oven drying and vacuum drying methods along with auxiliary processes were employed to improve the drying process and minimize the aggregation of the synthesized nanoparticles (NPs). Two auxiliary processes were used prior to drying in the oven to improve the performance of drying. Firstly, precipitates were immersed in ethanol to get replaced in place of water molecules in a week. The precipitates were then dried at room temperature for a week to evaporate their moisture. In vacuum drying method, only the second auxiliary process was employed. In freeze drying technique, the segregate and uniform nanospheres of V2O5 were produced with an average diameter of 37 nm. Generally, the employed additional treatments cause the drying techniques to enhance and the extent of particles aggregation to reduce. Finally, the application of the synthesized NPs as catalyst was investigated for the elimination of H2S from sour water with the initial concentration of 1300 ppm. The sour water was provided from Shiraz Oil Refinery Company. Results revealed that the synthesized NPs enable to completely eliminate hydrogen sulfide from sour water with 20% greater conversion at early contact seconds as compared to commercial V2O5 powder.