Surface-Area Enhanced Dealuminated Layered Double Hydroxides for Adsorption of Organic Compounds

Removal of isomorphously substituted Al from the layer of Zn-Al LDHs by treating with organic acids like para-toluenesulfonic acid, phenoldisulfonic acid followed by Ammonium hexafluro silicate under microwave irradiation result in increased surface area, generating materials which are highly mesoporous. The dealuminated Zn-Al LDHs were characterized by BET surface area, XRDand Al-27-NMR. Adsorption data of assynthesized and dealuminated Zn-Al LDHs for various polar and nonpolar organic compounds at different time intervals were evaluated. Adsorption data were fitted with the models such as fractional power, pseudo-first order and Elovich models. The Elovich model provided high degree of correlation. Modified Zn-Al LDH adsorbent showed increased adsorption of organic compounds compared to as-synthesized Zn-Al LDH because of high surface area. Reusability of used adsorbent showed almost same adsorption capacity as the fresh adsorbent.