Hexagonal (MCM-41) mesoporous materials were synthesized at 23 ℃ using hexadecyltrimethylammonium bromide (HDTMA) and tetramethyl-orthosilicate (TMOS) or Na-silicate. Products with (as-synthesized and dried at 23 or 70 ℃) HDTMA removed significant amounts oftrichlorethylene and tetrachloroethylene from water, similar to the behavior of organic-cation-exchanged smectites. Products without HDTMA (calcined) were weaker sorbents. Structural Al increased the sorption capacity of as-synthesized products but decreased that of calcined products. Structural Al and synthesis using TMOS both increased the stability of as-synthesized materials in 0.005 M CaCl{sub}2. All as synthesized materials have apparent Si solubilities between those of quartz and amorphous silica. Si dissolution rates for as-synthesized (using Na-silicate) products at pH ～7-8 are 2-3 orders of magnitude higher than those of quartz and 1 order of magnitude higher than that of glass. Rates show little ionic strength dependence in up to 0.1 M CaCl{sub}2 at Si concentrations up to three times quartz solubility. HDTMA leaching increased slightly with decreasing ionic strength; however only 1.5 is removed after exchange with 1050 pore volumes of H{sub}2O. The ease of synthesis, environmental stability, and significant sorption capacity indicate that as-synthesized MCM-41 materials could be used as sorbents for organic pollutants in water and as components of contaminant barriers.
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