Applications of surfactant-modified zeolites to environmental remediation

This paper summarizes recent work on environmental applications of surfactant-modified zeolite (SMZ), particularly for the removal of contaminants from water. SMZ was tested as a sorbent, and as a component of combined sorption/degradation media. Use of SMZ as a sorbent in a sub-surface permeable barrier was evaluated. A 15-week pilot test showed barrier retardation factors of 44 and 39 for chromate and PCE, respectively, similar to the values predicted from laboratory experiments. SMZ was also tested as a sorbent for organics present in oilfield wastewaters. Laboratory column experiments showed that major fuel components were effectively removed by SMZ and that the SMZ could be regenerated by air sparging. Finally, laboratory and field experiments showed that SMZ removed 99-100% of bacteria and viruses present in sewage effluent. The effectiveness of SMZ in combined sorption/degradation media was also evaluated. A permeable barrier pilot test with SMZ/zero-valent-iron pellets showed that chromate was totally removed from contaminated groundwater while PCE concentrations were reduced by two orders of magnitude. Finally, laboratory microcosm experiments showed that toluene-degrading organisms could be effectively cultured on SMZ. (C) 2003 Elsevier Inc. All rights reserved.