| Abstract
| - We determined the chemical and biological stability ofsurfactant-modified zeolite (SMZ) in laboratory batch andcolumn experiments. SMZ prepared using hexadecyltrimethylammonium (HDTMA)-Br or -Cl was stable in highionic strength and high- and low-pH environments, with morethan 90% of HDTMA remaining bound to the zeolitesurface after washing with 100 pore volumes. However,up to 20% of the HDTMA washed off in low ionic strengthsolutions (I< 5 mM) and up to 50% washed off in a 1.0mM Cs+ solution. HDTMA bound to the zeolite surface wasresistant to microbial degradation, with more than 98%of the original HDTMA remaining after 12−17 weeks ofincubation under aerobic or anaerobic conditions. Whileaqueous HDTMA was biocidal, HDTMA bound on SMZdid not inhibit microbial growth. On the basis of the resultsof this study, SMZ appears suitable as a sorbent for long-term in situ applications and as a substrate for enhancedbioremediation.
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