Highly ordered cobalt substituted MCM-41 samples were synthesized and characterized for application as catalytic templates for producing aligned single walled carbon nanotubes (SWNT). Highly reproducible Co-MCM-41 samples were successfully synthesized using alkyl templates with 10, 12, 14, 16, and 18 carbon chain lengths by direct incorporation of cobalt into the siliceous MCM-41 framework using a hydrothermal method; the pore size and the pore volume can be controlled precisely. The local environment of cobalt as determined by UV-vis spectroscopy is a mixture of tetrahedral and distorted tetrahedral structures similar to those observed in Co 3 O 4 . Cobalt atoms are uniformly distributed in the pores (about 30-40/pore) at nearly atomic dispersion probed by XAFS. Incorporation of cobalt into siliceous MCM-41 improves the structure, most likely by dehydroxylation and/or knitting the defective structure of the amorphous silica polymer. The optimum crystallization temperature and time were 100 °C and 4 days for siliceous MCM-41 and 6 days for Co-MCM-41, respectively. Co-MCM-41 is very stable against reducing and oxidation conditions at temperatures under 750 °C. The catalytic templates showed over 90% selectivity to SWNT with up to 4 wt % carbon yield. The growth of SWNT in the pores of Co-MCM-41 was confirmed by Raman spectroscopy and TEM. The catalytic template maintained its structure after successive reaction cycles, which suggests that Co-MCM-41 is a very stable template for producing SWNT under harsh reaction conditions.

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Adsorption isotherms for an homologous series of primary aliphatic alcohols from aqueous solution by montmorillonite and kaolinite saturated with either sodium or calcium ions have been determined. The results show that adsorption is a function of chain length and exchangeable cation in the case of the more insoluble alcohols. Exchangeable cation does not affect the adsorption of the soluble alcohols to any significant extent. Adsorption of the longer chain alcohols occurs in voids in the mineral aggregates.

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The effective free diameter of the parallel, nonintersecting channel system of offretite has been modified in various ways using synthetic crystals initially containing K and tetramethylammonium (TMA) ions. Objectives were to optimize the openness of the channels and to produce sorbents having regulated molecule sieving properties. Removing all TMA from the wide, parallel channels by exchange and enriching the crystals in Li, Na, K, or Cs yielded open sorbents which sorbed n-hexane very rapidly and which differed only marginally in rapid rates of uptake of 2,2-dimethylbutane. Removal of all TMA from gmelinite cages and wide channels by heating in air or oxygen also yielded open M,K,H-offretites (where M = Li, Na, K, or Cs). However, the sieve behavior and capacity were further modified according to the temperature and number of oxidative treatments. Crystals enriched in methyl-, dimethyl-, and trimethylammonium sorbed n-hexane at rates which differed inter se. Small amounts of TMA in the wide channels also strongly influenced the kinetics of sorption of n-hexane and large amounts prevented any uptake at all.

A study has been made of the effect of salt inclusion in certain zeolites upon the kinetics of sorption of, and the molecule sieving behaviour shown towards, n-hexane, 2-and 3-methyl pentanes, 2,2-and 2,3-dimethyl butanes, cyclohexane and benzene. The zeolites selected provided three typical one dimensimal channel systems. They were zeolite L, offretite and H-mordenite. The salts used to impregnate the channels were KCl, KBr, KzS04 and K2Cr04, all comparatively stable to heating. The effects of salt concentration and salt type were investigated in each zeolite and also of washing and extraction of salt-impregnated sorbents. Among the above salts K2Cr04 gave the largest effects. Access to the channels could be selectively controlled and changed by salt imbibition giving rise to various separation possibilities based on differences in size and shape of sorbate molecules. " , 6.7x7.0 c " , 7.5 1 3093 J mordenite as above (salt K6*61[A16*6lSi4009d impregnated : outgassed 360°C) a Approximate values because of treatments given or compositional differences from type Composition of type material, ref. (19). materials, ref. (18). b Compositions from ref. (11). Compositions from ref. (17).