科研之友
微信
新浪微博
Facebook
分享链接
摘要
Nano-magnesium hydroxide@fly ash composite with core-shell structure was prepared with non-uniform nucleation method taking fly ash as the carrier, MgCl2 and NaOH as reaction coating agents according to the idea of "particle design" and its adsorption properties of Cu(II), Ni(II) and Pb(II) in wastewater were studied. The composite powders before and after coating were characterized by scanning electron microscopy (SEM), energy dispersive (EDS), specific surface area analyzer (BET), X-ray diffraction (XRD) and infrared spectroscopy (FTIR). The results show that the surface of the composite powder is uniformly coated with a large amount of nano-magnesium hydroxide and a small amount of hydrated magnesium carbonate, the specific surface area increased to more than 30 times of the original (fly ash 1.79 m2/g), the average pore size increased from 11 nm to 14.7 nm, and the average pore width increased from 12.8 nm to 15.4nm, respectively. Si-O-C-O-Mg and Si-O-Mg-OH are formed between Si-O-Si, Si-O-C and magnesium hydroxide on the surface of fly ash. The removal efficiency of heavy metals by the composite powder is significantly higher than that of fly ash, and the unit saturated adsorption capacity reaches 216.30, 160.96 and 116.50 mg/g. According to Zeta potential, FTIR and simulation equations, the adsorption mechanism of heavy metal ions by composite powder was analyzed. The results show that the composite adsorbs heavy metal ions through precipitation reaction, electrostatic attraction and ion exchange, etc. The adsorption process isotherm, the kinetics and the thermodynamics conform to the Langmuir isotherm model, intraparticle diffusion model and spontaneous endothermic reaction, reapectively. The desorption experiment indicates that the composite powder has a good regeneration performance in the adsorption process.
- 单位
