富里酸吸附TNT的环境影响因素

采用振荡平衡法对富里酸(FA)吸附TNT的主要环境影响因素以及其热力学特性进行了研究。结果表明:随着pH值的升高,FA对TNT的吸附量先减少后增加,pH=7.0时吸附量最小;随着离子强度(IS)的增大,FA对TNT的吸附量逐渐增加;随着温度的升高,FA对TNT的吸附量逐渐减少;ΔH0=-5.62 kJ/mol、ΔG0 S0 < 0,表明FA对TNT的吸附为自发的放热反应,且吸附过程中系统的无序性降低。FA对TNT的吸附机制主要包括范德华力、疏水作用、偶极作用力以及氢键力,并且范德华力和疏水作用会随着温度的升高逐渐减弱。

Influence of environmental factors on adsorption of TNT on fulvic acid

The environmental factors influencing the adsorption of TNT on fulvic acid (FA) were investigated using batch equilibrium experiments in this work, and the adsorption thermodynamics were further calculated. The obtained results showed that the adsorption capacity of FA for TNT tended to decrease initially and then increase with increasing solution pH, with a turning point at pH=7.0. The TNT adsorption capacity gradually increased with increasing ionic strength and decreasing temperature. ΔH0 value of -5.62 kJ/mol and negative ΔG0 and ΔS0 values indicated that the adsorption of TNT on FA was a spontaneous exothermic process, and the disorder of the adsorption system decreased in the process. The adsorption mechanisms of TNT on FA were mainly van der Waals forces, hydrophobic interaction, dipole forces, and hydrogen bonds, and the van der Waals forces and hydrophobic interaction would weaken with increasing temperature.