Characterization of Nonequilibrium Sorption of Gasoline Components by Surfactant-Modified Zeolite

Authors: Joshua A. Simpson and Robert S. Bowman, New Mexico Technological University, Socorro, NM

Venue: 44th Annual Meeting of the Clay Minerals Society in Santa Fe, NM, June 3–7, 2007 (http://www.clays.org/home/HomeAnnualMeeting.html [external site]).

Abstract: Surfactant-modified zeolite (SMZ) has been shown to effectively remove benzene, toluene, ethylbenzene, and xylene (BTEX) from water generated during oil and natural gas production (produced water). The BTEX sorption isotherms are linear and noncompetitive, suggesting that the removal mechanism is partitioning into the surfactant’s hydrophobic bilayer formed on SMZ. Even though BTEX sorption in batch systems is rapid, chemical equilibrium models do not accurately describe BTEX transport through packed beds of SMZ. Comparison with transport of a nonreactive tracer (tritium) suggests that two-site, diffusive nonequilibrium sorption-desorption controls BTEX transport. We conducted batch experiments with SMZ to determine the nonequilibrium sorption kinetics of each BTEX constituent. The kinetic measurements were used to parameterize a nonequilibrium transport model to predict BTEX removal under varying flow conditions. The accuracy of predictions is being tested using laboratory column experiments with produced water from the San Juan Basin of New Mexico.

Related NETL Project: The primary goal of the related NETL project entitled “Long-Term Field Development of a Surfactant-Modified Zeolite/Vapor-Phase Bioreactor System for Treatment of Produced Waters for Power Generation” (DE-FC26-04NT15546) is to conduct a long-term field test of a prototype Surfactant-Modified Zeolite/Vapor-Phase Bioreactor (SMZ/VPB) treatment system for removing dissolved organics from produced water prior to demineralization to produce a water that can be used by utilities or other industrial users.

NETL Project Contacts
NETL - Jesse Garcia (Jesse.Garcia@netl.doe.gov or 918-699-2036)
UT - Lynn Katz (lynnkatz@mail.utexas.edu or 512/ 471-4244)