Zeolite/adsorbate systems organic compounds

Highly dealuminated Y zeolite, commercially labeled as DAY (dealuminated Y), with an FAU framework type is an excellent adsorbent for the removal of organic compounds in wastewaters, as a consequence of the hydrophobic surface properties of this zeolite, owing to the low concentration of A1 (see Section 2.5.1). As an example of adsorption in a zeolite, in Figure 6.9, the N2 adsorption isotherm at 77 K of the DAY zeolite, DAY-20 F (Si/Al = 20), provided by Degussa AG, Dusseldorf, Germany, is shown. The N2 adsorption isotherms were measured with an Accelerated Surface Area and Porosimetry System (Autosorb-1) from Quantachrome, Boynton Beach, FL, USA [21] which is a volumetric automatic equipment similar to that reported in Figure 6.8. 

Recently, rotor-type adsorption systems attract much attention, because the systems can effectively control humidity and air pollutants such as volatile organic compounds (VOCs), nitrogen oxide (NOx) and sulfiuic oxide (SOx). Gas remediation efficiency is principally concerned to the gas capturing ability of the adsorbents impregnated into the ceramic honeycomb rotor such as zeolite, silica, activated carbon, etc. Therefore, it is one of the most important works to develop the adsorbent with good absorption-desorption behaviors. 

Recently, great attention has been paid to the ambient temperature adsorption for removing sulfur compounds from natural gas, as the system is simple and is quick and easy to be started up. The major adsorbents that were used in the ambient temperature adsorption are AC-based and zeolite-based materials. The Osaka Gas mixed metal and metal oxide catalyst provides a low-temperature method of desulfurization. The catalysts (or adsorbents) is claimed to remove organic sulfur and H2S at room temperature.115... 

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