Preparation Of Core-shell Organic-inorganic Hybrid Material And Application In Heavy Metal Wastewater

In recent years, environmental pollution accidents caused by the discharge of heavy metals wastewater have occured frequently. It is urgent to find a scientific and effective method to solve the pollution of heavy metal. Adsorption is a popular and promising separation technique for water decontamination, The key of adsorption is adsorption materials. With the heavy metal pollutions becoming more and more serious, traditional adsorption materials have been unable to reach the new requirements. At present, it is very important to develop a new functional adsorption material.In this paper, core-shell organic-inorganic hybrid materials were prepared through distillation precipitation polymerization with 400 nm silica microspheres as inorganic core. Furthermore, the adsorption of hybrid nano material was also studied, the details were as follows:1. Aminated hybrid microspheres for Cd(II), Cu(II) and Pb(II) adsorptionWith methacrylic acid(MAA) as the polymer monomer, we prepared core-shell hybrid microspheres P(MAA-co-EGDMA)/Si O2 by distillation precipitation polymerization, through diethylenetriamine(DETA) to modify the hybrid microspheres to acquire amine hybrid microspheres P(DETA-co-EGDMA)/Si O2. The aminated hybrid microspheres were characterized by elemental analysis which found that N element amount of microspheres was 2.91%. Furthermore, aminated hybrid microspheres were also systematically characterized by transmission electron microscopy(TEM), infrared spectrum(FT-IR), thermogravimetric analysis(TGA). The adsorption behavior of aminated hybrid microspheres on heavy metal ions Cd(II), Cu(II) and Pb(II) was investigated. The effects of different experimental conditions, such as adsorbent dosage, p H, temperature, initial concentration, contact time were performed in batch adsorption. The result showed that aminated hybrid microspheres exhibited excellent adsorption capacity on Cd(II), Cu(II) and Pb(II). At 303 K, the maximum adsorption capacities of aminated hybrid microspheres were 37.00 mg·g-1 for Cd(II), 47.50 mg·g-1 for Cu(II) and 72.75 mg·g-1 for Pb(II), respectively. The regeneration ratios of aminated hybrid microspheres for Cd(II), Cu(II) and Pb(II) were 88.81%, 90.86% and 90.13% after three times desorption experiments, respectively. The isothermal adsorption experiments showed that the Langmuir adsorption isotherm model was suitable to describe the adsorption behavior of amine hybrid microspheres adsorption on Cd(II), Cu(II) and Pb(II).The thermodynamics analysis showed that the adsorption reaction of amine hybrid microspheres was endothermic reaction which the rising of temperature was beneficial to adsorption. The adsorption kinetics experiment showed that the pseudo-second order model could describe the adsorption behavior of amine hybrid microspheres well.2. Imidazole hybrid microspheres for Cd(II), Cu(II) and Pb(II) adsorptionCore–shell poly(vinyl imidazole-co-ethylene glycol dimethacrylate)/silica(P(VI-co-EGDMA)/Si O2) microspheres were prepared through distillation precipitation polymerization, in which vinyl imidazole donated the functional imidazole groups. The morphology and chemical structure of imidazole hybrid microspheres were probed using transmission electron microscopy(TEM), fourier transform infrared(FT-IR), and thermogravimetric analysis(TGA). Elemental analysis showed that N element amount of imidazole hybrid microspheres was 3.15%. The adsorption properties on Cd(II), Cu(II) and Pb(II) of P(VI-co-EGDMA)/Si O2 were systematically investigated,which was found that the maximum adsorption capacities of imidazole hybrid microspheres were 51.25 mg·g-1 for Cd(II), 34.00 mg·g-1 for Cu(II) and 88.50 mg·g-1 for Pb(II) under 303 K, respectively. The adsorption process belonged to chemical adsorption and obeyed Langmuir isotherm model and pseudo-second order model. After three times desorption experiments, the regeneration ratios of imidazole hybrid microspheres for Cd(II), Cu(II) and Pb(II) were 94.40%, 91.20% and 92.90%, respectively.