The Crosslinking Coordination Synthesis Of Metal Complex And Oxidative Degradation Of Udmh Wastewater

In recent years,developing routes to produce materials based on green chemistry,which minimizes pollution,have been focused on.With the rapid development of the aerospace industry,the large consumption of UDMH unfortunately results in a large amount of wastewater.The efficiently and green catalysts to abate the environmental loads are needed to degrade UDMH.In this paper the catalyst was combined into the process of catalytic wet peroxide oxidation(CWPO)for the degradation of UDMH wastewater with H2O2.In this study a series of M@chitosan and M@silica-chitosan experiments were.conducted to verify the feasibility of these two catalysts,and obtained the optimum operating conditions.Nonprecious-metallic ions,Cu? and Co? immobilized on silica-chitosan(CS)hybrid material(Cu-M@CS-SiO2,Co-M@CS-SiO2)were developed as a green nanocatalyst for degrading 1,1-dimethyl hydrazine(UDMH)wastewater.And the degradation rate is more than 60%.Using the same metal cation but different kinds of anionic salt prepared catalysts to degrade dimethylhydrazine wastewater,the conclusion can be draw that anion types have no effect on the activity of catalysts.But because the chitosan of acid soluble,it can't meet the requirement of stability in degrading dimethylhydrazine.To reduce the loss of effective components in catalysts and improve the catalytic performance,chitosan is carried on the inert support SiO2.In different active centers of the modified carrier catalyst,one of the best in the copper series catalysts is Cu-Zn@CS-SiO2,which obtaining the high efficiency of UDMH degradation and COD removal(100%in 10 min and 87.38%in 30 min,respectively)and the low concentration of NDMA(0.31 mg/L),while one of the best in the cobalt series catalysts is Co-Cu@CS-SiO2,which obtaining the high efficiency of UDMH degradation and COD removal(100%in 10 min and 84.14%in 30 min,respectively)and the low concentration of NDMA(4.90 mg/L).Based on the research of the two series of catalysts,manganese and zinc ions as auxiliary ion to degrade dimethylhydrazine intermediate product NDMA efficiently.Based on the study of Cu-Zn@CS-SiO2 catalyst activity,the optimal H2O2 dosage was 3 mL,temperature 65? and catalyst activity was less affected after being used for 6 times.By combining SEM,XRD,EDX,and FT-IR results,we speculated that Fe(?)was hexacoordinated to chitosan molecules,complexing through two O and two N atoms of the CS-SiO2 polymer and water molecule,while Cu(?)or Zn(?),Mn(?),Co(?),Ni(?)was tetracoordinated to chitosan molecules and chelated with N atoms of the CS-SiO2 polymer.