###### Abstract  
To determine the interactions between TNT and aniline adsorptions and the potential to enhance their transports in saturated Chinese loess, batch and column tests were conducted. The batch tests show that their adsorptions inhibit each other when they coexist, and their inhibitions depend on their concentrations, implying that their coexistence has the potential to enhance their transports of each other in the saturated loess. The column tests confirm this speculation, while aniline enhances TNT transport more obviously than TNT does. These findings are ascribed to TNT adsorption being primarily through surface adsorption, while aniline adsorption mainly takes place via electrostatic adsorption and inner pore diffusion adsorption, as well as surface adsorption. There is a certain competitive relationship in their adsorptions on the loess because they have same and different adsorption sites; in particular, electrostatic force is greater than surface force. Therefore, these inhibitions on adsorption are conducive to the existences of TNT and aniline in the water rather than being fixed on the loess, thus enhancing their transports in the saturated loess, indicating that their coexistence can increase the risk of soil and even groundwater pollution. TNT; aniline; transport; pollutants coexistence; Chinese loess Article  
Exploring the Potential of TNT and Aniline Coexistence to Enhance Their Transports in Saturated Chinese Loess  
remains in or near the soil surface, and TNT concentration and its plume are smaller than the associated RDX in the studied groundwater [11]. However, [PERSON] and [PERSON] (2011) [12] reported that the concentration of TNT (4 mg/L) was higher than RDX concentration (2.5 mg/L) in their studied groundwater. Obviously, there is an inconsistency between the two studies and that is a puzzle. Although the inconsistency is likely due to microbial activity, no specific microorganisms were identified to be responsible for the degradation of these organic pollutants [13]. In our view, we speculate that the inconsistency might strongly depend on the coexistence of multiple organic pollutants in the soil-water system, which then result in certain interacting behaviors, including adsorption and transport among coexisting pollutants. And yet, to the best of our knowledge, little attention has been given to exploring the interactions and competitive effects of one organic pollutant on the other, and no specific study conducted to solve the puzzle has been reported. Loess is a special soil extensively distributed in Central Asia, the Middle East, Russia and North America [13]. The Loess Plateau in north-central China is the most concentrated and largest loess area. It is generally considered that the loess is transported by air and then deposited in the manner of a loosely packed soil skeleton without chemical weathering. The loess particles are mainly silty quartz with dimensions of less than 75 um, and the small quartz grain is reported to be produced by energetic processes like glacial grinding and tectonic activities [14]. In general, partition is always involved unavoidably in the process of objective pollutant adsorption on the studied medium because soil organic matter (SOM) is an important part of the soil or sediment [15], and thus it is difficult to determine the contribution of adsorption and characterize the interactions of coexisting pollutants. Unlike other soil, loess is very low in SOM, with calcite as the main component [14]. Meanwhile, lots of studies have proved that loess has great potential as a promising adsorbent to adsorb numerous pollutants including organic compounds (such as TNT, aniline, toluene and naphthalene) [16; 17] and heavy metals (such as Cd, Pb and Zn) [13; 18]. Hence, given these aspects, loess is an ideal adsorbent in natural environmental pollution remediation for studying interactions of multiple organics.