Nitroaromatic explosives are major pollutants produced during wars that cause serious environmental and health problems. The removal of a typical nitroaromatic explosive, 2,4,6-trinitrotoluene(TNT), from aqueous solut...Nitroaromatic explosives are major pollutants produced during wars that cause serious environmental and health problems. The removal of a typical nitroaromatic explosive, 2,4,6-trinitrotoluene(TNT), from aqueous solution, was conducted using a new recyclable magnetic nano-adsorbent(Fe@SiO_(2) –NH_(2)). This adsorbent was prepared by grafting amino groups onto Fe@SiO_(2) particles with a well-defined core-shell structure and demonstrated monodispersity in solution. The removal performance of the nano-adsorbent towards TNT was found to be 2.57 and 4.92 times higher than that towards two analogous explosives, 2,4-dinitrotoluene(2,4-DNT) and 2-nitrotoluene(2-NT), respectively, under neutral conditions. The difference in the removal performance among the three compounds was further compared in terms of the effects of different conditions(pH value, ionic strength, humic acid concentration, adsorbent modification degree and dosage, etc.) and the electrostatic potential distributions of the three compounds. The most significant elevation is owing to modification of amino on Fe@SiO_(2) which made a 20.7% increase in adsorption efficiency of TNT. The experimental data were well fit by the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model, indicating multilayer adsorption on a heterogeneous surface. The experimental results and theoretical considerations show that the interactions between Fe@SiO_(2) –NH_(2) NPs and TNT correspond to dipole-dipole and hydrophobic interactions. These interactions should be considered in the design of an adsorbent. Furthermore, the adaptability to aqueous environment and excellent regeneration capacity of Fe@SiO_(2) –NH_(2) NPs makes these remediation materials promising for applications.展开更多
基金supported by the National Natural Science Foundation of China(No.21677177)the Science Foundation of China University of Petroleum-Beijing(No.2462020XKJS04)+1 种基金the Beijing Municipal Science&Technology Commission(No.Z181100005318002)the China Postdoctoral Science Foundation(No.2018M631491)。
文摘Nitroaromatic explosives are major pollutants produced during wars that cause serious environmental and health problems. The removal of a typical nitroaromatic explosive, 2,4,6-trinitrotoluene(TNT), from aqueous solution, was conducted using a new recyclable magnetic nano-adsorbent(Fe@SiO_(2) –NH_(2)). This adsorbent was prepared by grafting amino groups onto Fe@SiO_(2) particles with a well-defined core-shell structure and demonstrated monodispersity in solution. The removal performance of the nano-adsorbent towards TNT was found to be 2.57 and 4.92 times higher than that towards two analogous explosives, 2,4-dinitrotoluene(2,4-DNT) and 2-nitrotoluene(2-NT), respectively, under neutral conditions. The difference in the removal performance among the three compounds was further compared in terms of the effects of different conditions(pH value, ionic strength, humic acid concentration, adsorbent modification degree and dosage, etc.) and the electrostatic potential distributions of the three compounds. The most significant elevation is owing to modification of amino on Fe@SiO_(2) which made a 20.7% increase in adsorption efficiency of TNT. The experimental data were well fit by the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model, indicating multilayer adsorption on a heterogeneous surface. The experimental results and theoretical considerations show that the interactions between Fe@SiO_(2) –NH_(2) NPs and TNT correspond to dipole-dipole and hydrophobic interactions. These interactions should be considered in the design of an adsorbent. Furthermore, the adaptability to aqueous environment and excellent regeneration capacity of Fe@SiO_(2) –NH_(2) NPs makes these remediation materials promising for applications.
