Removal Of Antimony(Ⅲ) By Adsorption Of Modified Carbon Nanotubes

With the acceleration of China’s industrialization process and the improvement of urbanization, the trace heavy metals and toxic organic pollutants in source of drinking water in many cities were significantly increased. The security situation of water quality becomes worse. Antimony (Sb) is a naturally occurring toxic elements, as an important strategic resource, antimony is widely used in brake pads, flame retardants, pharmaceutical and other industries. Over the last decade, the demand for and consumption of human antimony doubled, promote the large-scale development of the antimony ore resources, which to some extent increased the content of antimony in water environment. Coupled with the current our country is still not to make corresponding regulations for the standards of antimony industrial wastewater emission, antimony contamination of water bodies are getting worse. Previous studies have showed that the remove of antimony is difficult, and in addition to the existing antimony technologies research is still obviously insufficient, to this end, the removal of antimony has been further discussed in this paper to seek advanced and efficient antimony removal method. In this paper, carbon nanotubes, a new type of nanomaterials with properties quite different from the conventional adsorption materials, are used as a supporter. The new composite materials (Fe2O3/CNT and MnO2/CNT) are prepared by metal oxide load-modified method, and the adsorption behaviors and adsorption mechanism of Sb(Ⅲ) have been investigated in detailed.In first section the method of liquid chemical deposition is used to form the composite adsorbent with carbon nanotubes and Fe2O3for Sb(Ⅲ) removal. The Fe2O3modified CNTs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser particle size analyzer, BET and Fourier transform infrared spectrometer (FTIR). Parameters affecting the adsorption efficiencies including solution pH value, initial Sb(Ⅲ) concentration, adsorbent dosage, contact time and temperature were investigated. The results indicate that the removal rate of Sb(Ⅲ) by Fe2O3modified CNTs was99.97%under the initial Sb(Ⅲ) concentration of1.5mg/L, adsorbents dosage of0.5g/L, temperature of298K, and pH value of7.00, which was29.81%higher than that of the raw CNTs. The adsorption capacity correspondingly increased from3.01mg/g to6.23mg/g. The equilibrium adsorption data can be fitted to the Freundlich adsorption isotherm. In addition, it has been found that the adsorption efficiency is almost free from the influence of the pH values.The remove of antimony by MnO2modified CNTs was studied in the second section. The method of liquid redox is used to form the composite adsorbent with CNTs and MnO2.The MnO2modified CNTs were characterized by X-ray diffraction (XRD), SEM, TEM, laser particle size analyzer and BET. Parameters affecting the adsorption efficiencies including solution pH value, initial Sb(Ⅲ) concentration, adsorbent dosage, contact time and temperature were investigated. The results indicate that the removal rate of Sb(Ⅲ) by MnO2modified CNTs was97.72%under the initial Sb(Ⅲ) concentration of1.5mg/L, adsorbents dosage of0.5g/L, temperature of298K, and pH value of2.00, which was51.29%higher than that of the raw CNTs. The adsorption capacity correspondingly increased from3.01mg/g to6.00mg/g. The equilibrium adsorption data can be fitted to the Freundlich adsorption isotherm. In addition, it has been found that the pH values have great impacts on the adsorption efficiency. At the pH about2, the remove efficiency is well, while at other pH, the results are not satisfactory.The research shows that the Fe2O3/CNT and MnO2/CNT have greater removal capacities for Sb(Ⅲ) in the solution than some other conventional materials, and Fe2O3/CNT is better than MnO2/CNT. It also provides an efficient, economic and easy approach to handle hazardous trace ion solution.