Enhancing the attenuation of explosives in surface soils at military facilities: Sorption‐desorption isotherms

Abstract

The primary objective of the present study was to develop inexpensive soil amendments that can be applied to enhance the adsorption of energetic compounds on military training ranges, thus limiting the potential for these compounds to migrate to groundwater. Adsorption and desorption isotherms were determined for 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine with a wide variety of natural and man-made adsorbents, including wheat straw, sawdust, peat moss, ground rubber tires, and clays. Among the various adsorbents tested, peat moss proved to be the most effective sorbent for the three explosives. The adsorption coefficients (Kd(s)) for TNT and RDX with peat (310 and 87 L/kg, respectively) were at least two orders of magnitude higher than that determined for adsorption of these energetics with two surface soils. The adsorption-desorption isotherms for the explosives showed considerable hysteresis (Kd(s) < Kd(d)) with some of the solid adsorbents, suggesting that the sorption process is not readily reversible but, rather, that some fraction of the adsorbed contaminant is either irreversibly bound or present as a slowly desorbed fraction. The data indicate that the application of specific adsorbents to soils at military impact ranges may significantly improve the protection of local groundwater resources.

Immobilization of Energetics on Live Fire Ranges (CU-1229). Revision 1.0

“…This assumption has been proven invalid for some classes of pollutants (i.e., pesticides and polychlorinated biphenyls [23,24]), and several researchers have noted the formation of sorbed and less or nonbioavailable pools of aged TNT in soil [25][26][27]. However, our research and other published literature indicate that RDX and HMX sorb to a much lower degree than does TNT [21,28]. Extractability of RDX also has been observed to remain greater over time than that of TNT [27,29].…”

“…Based on extensive research that has been done on the biodegradation and biotransformation of explosive compounds by bacteria (for review see refs (14,18,21)), fungi (5,6,12,32,36,40,46) and plants (8,16,22,30,45), other approaches for remediating explosive compounds-contaminated soils have been developed.…”

“…In the companion paper also in this issue [21], the adsorption to and desorption from several different materials (i.e., peat moss and sawdust) of TNT, RDX, and HMX was examined. The research reported here focused on stimulation of explosives biodegradation by various cosubstrates, and determination if explosives sorbed to peat moss and sawdust could be biodegraded when effective cosubstrates are present.…”

Treatment of Waters Containing the Thiocarbamate Herbicide Molinate through an Adsorption/Bio-Regeneration System using a Low-Cost Adsorbent

“…It is obtained in granular form directly from industries specialized in tire recycling. In previous studies, when compared with other lowcost adsorbents, GTR was among those with the best solute removal efficiencies (Alam et al 2000;Purakayastha et al 2003;Hatzinger et al 2004). Some of the organic compounds tested for adsorption by GTR have been anionic surfactants (Purakayastha et al 2005a, b), herbicides (2,4-D and atrazine; Alam et al 2000Alam et al , 2002Alam et al , 2005, and different alkanes and solvents (Rangarajan et al 1999).…”

“…These were applied in different contexts: adsorption of benzene and o-xylene from leaking underground fuel storage tanks (Kershaw et al 1997), retention of explosive compounds in military training ranges (Hatzinger et al 2004), and mitigation of fertilizer leaching in golf course putting greens (Lisi et al 2004).…”