ENHANCED RECOVERY OF THE EXPLOSIVE HEXAHYDRO-1,3,5-TRINITRO-1,3,5-TRIAZINE (RDX) FROM SOIL - CYCLODEXTRIN VERSUS ANIONIC SURFACTANTS

The extraction of RDX (I) from soil (1,000 ppm) was studied using 10 m t volumes of water and 1 % w/v aqueous solutions of sodium dodecyl sul fate (SDS), sodium lignosulfonate (Lignisite 458), Lignosol, hydroxypr opyl-B-cyclodextrin (hp-B-CD), and methyl-B-cyclodextrin (Me-B-CD). Th e anionic surfactants SDS, Ligniste 458 and Lignosol increased RDX rec overy to 1.2, 2.0 and 1.6-fold that of water (37.7 ppm), respectively. Extracted RDX was accompanied by hydrolysis as evidenced by the forma tion of 3,5-dinitro-1,3,5-triazacyclohex-1-ene (R). Similar RDX recove ries were obtained using the cyclodextrins hp-B-CD and Me-B-CD, i.e., 2.4 and 1.5- fold that of pure water, respectively. In contrast to the ionic additives no RDX hydrolyzed products were observed during the c yclodextrin assisted extraction. In one case we found that RDX recover y from the soil increased with the concentration of the cyclodextrin a nd reached a value of 95% (ca 4.5- fold that of water) when a 10 % w/v solution of hpB-CD was used. Copyright (C) 1996 Elsevier Science Ltd