Chitosan–silica nanoparticles catalyst (M@CS–SiO2) for the degradation of 1,1-dimethylhydrazine

Hybrid materials of chitosan–silica (CS–SiO 2 ) with nonprecious-metallic ions (Cu) immobilized on (Cu–M@CS–SiO 2 ) were developed as green catalysts for degrading 1,1-dimethyl hydrazine (UDMH) wastewater. SEM, XRD, EDX, and FT-IR were employed for characterizing the catalysts. Results indicated that metal ions were chelated with N or N and O atoms of CS–SiO 2 . The efficiency of UDMH degradation, chemical oxygen demand (COD) removal and the concentration of N -nitrosodimethylamine (NDMA) were used to evaluate the catalytic activity. The catalysts were firstly combined into the process of catalytic wet peroxide oxidation (CWPO) for the degradation of UDMH wastewater with H 2 O 2 . Based on the study of the effects of different metallic ions, anions and reaction factors on the catalyst activity, the optimal conditions for CWPO with M@CS–SiO 2 were determined, the H 2 O 2 dosage and temperature were 3.0 mL and 65 °C, respectively. Under these conditions, the treatable UDMH concentration was 500 mg L −1 , 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 −1 ). The catalyst activity was less affected within six reaction cycles. Meanwhile, owning a huge surface area and strong adsorption performance, this kind of hybrid material can rapidly degrade, adsorb, and separate pollution.