Research On Separation Characteristics Of Elements In VIB From Solution Onto Iron-based Oxide

In recent years, the phenomenon of heavy metals pollution in the water has become more serious and the treatment of wastewater containing heavy metals is becoming a hot topic of research. The topic of this research is adsorption and separation characteristics of ⅥB elements in the water.The waste water containing vanadium, tungsten which was produced by waste SCR catalyst recycling process and surface water suffered heavy metal of molybdenum contamination act as a typical representative. The purpose of research is new approach of cheap, efficient, environment-friendly is created.The researches focus on adsorption and separation characteristics of iron-based oxide nanoparticles for VIB element in solution. Experimental results show that iron-based oxide nanoparticles adsorb different ions of VIB elements from solution mainly due to different surface electric charge on iron-based oxide nanoparticles and different ionic aggregation of VIB elements. Adsorption of VIB element ions comply Sips isotherm model and iron-based oxide nanoparticles adsorption kinetics indicated that the adsorption process was controlled by ionic diffusion and surface reaction.The recovery of valuable metals from waste catalyst needs to add the alkali liquor to dissolve metals and then add acid to adjust the pH to conduct vanadium, tungsten separation. The results of iron-based oxide nanoparticles adsorptive experiments showed that iron-based oxide nanoparticles can separate tungsten\vanadium each other in solution under condition of pH=1 and 10 min adsorptive time. For reusing of vanadium (V) from SCR waste catalyst, vanadium (V) was adsorbed by iron-based oxide nanoparticle and then adsorbent was prepared as catalyst. The maximum adsorptive capacity of adsorbent was 68.5 mg/g at around pH=3. The vanadium species coexist in solution indicate the adsorption process of iron-based oxide was mainly adsorption on external surface of the layers owing to charges on the surface. The adsorbent after adsorption of vanadium (V) was first tested and used as a heterogeneous Fenton like catalyst. It was found that the adsorbent after adsorption of vanadium (V) possess a catalytic activity towards the decoloration of Methyl Orange in the presence of H2O2 in pH=3.A novel combination of magnetic adsorptive and coagulative strategy which was applied to remove molybdenum (Mo) ions from surface water was investigated in this study. The coagulation performances of ferromagnetic nanoclusters-ferric flocs were compared under different pH conditions and dosages. The better performance of molybdenum removal from water at pH 5-8 and the removal of molybdenum increases with pharmaceutical dosage. The ferromagnetic nanoclusters and ferromagnetic nanoclusters-ferric flocs composite coagulant were characterized in terms of typical properties, structure and morphological analysis (TEM, XRD, M-H Hysteresis Curves, Particle Size Distribution). The better removal performance of Mo could be attributed to the co-effect of ferromagnetic nanoclusters and ferric flocs. Meanwhile, in order to satisfy the national drinking water criterion, the reinforce effect of ferromagnetic nanoclusters on reducing the concentration of ferric (Fe) ions in effluent makes sure that the content of iron ions under 0.3mg/L. The experimental results indicate that mechanism of the molybdate removal was a physical surface adsorption which might combine with chemical action.