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Effect of the atomic active metal ratio in Al/Fe-, Al/Cu- and Al/(Fe–Cu)-intercalating solutions on the physicochemical properties and catalytic activity of pillared clays in the CWPO of methyl orange

Paper ID Volume ID Publish Year Pages File Format Full-Text
47169 46462 2010 11 PDF Available
Title
Effect of the atomic active metal ratio in Al/Fe-, Al/Cu- and Al/(Fe–Cu)-intercalating solutions on the physicochemical properties and catalytic activity of pillared clays in the CWPO of methyl orange
Abstract

The effect of the composition of the intercalating solutions in the catalytic performance of the derived pillared clays has been studied. A Colombian bentonite was treated with Al/Fe-, Al/Cu- and Al/(Fe–Cu)-solutions, and the resulting pillared solids were used in the catalytic wet peroxide oxidation (CWPO) of the azo dye methyl orange (MO) in aqueous solutions. The active metal ratio (AMR), here defined as the atomic percent ratio between the active metals (Fe and Cu) and the total content of metals (Al, Fe and/or Cu) in the intercalating solutions, was found to be a key factor for the properties of the pillared solids. Low AMR values, between 0 and 10%, were considered, and the efficiency for the incorporation of the active metals into the layered structure was followed by chemical analyses and cationic-exchange capacity measurements. Further characterization studies were carried out by X-ray diffraction, H2 temperature-programmed reduction, scanning electron microscopy/energy dispersive X-ray analysis, nitrogen adsorption at −196 °C and thermal analysis. Considering the physicochemical properties together with the catalytic performance, it is proposed that isomorphic incorporation of the active metals into the Al13-like polycations may take place. The obtained pillared solids exhibited better catalytic performance as the AMR values were lowered in the corresponding intercalating solutions, displaying also high stability to chemical leaching into the strongly oxidizing environment of the catalytic reaction, especially in the binary Al/Fe- and Al/Cu-systems. The Al/Fe-pillared clays attained most of their maximal removal of the azo dye in solution after only 1 h of reaction at very mild experimental conditions (room temperature and atmospheric pressure of 18 °C and 0.7 atm).

Graphical abstractIn the preparation of mixed Al/Fe- and Al/Cu- pillared clays, at least three kinds of metal species are proposed to take place. The catalytic performance of the resulting materials in the CWPO of methyl orange (MO), is higher per active site of the metals as their stabilization in the form of true mixed pillars is favoured without significant worsening of the textural properties by effect of the other species. This is achieved when lower atomic metal ratios (AMR) are employed in the preparative procedure.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ True mixed Al/Fe-, Al/Cu-pillars may take place in the preparation of PILCs. ▶ Fe is 15 times more efficiently stabilized than Cu in mixed Al-based PILCs. ▶ Low AMR values promote mixed Al/Fe-, Al/Cu-PILCs with better textural properties. ▶ Al/Fe-PILCs prepared with low AMR are excellent catalysts in the CWPO reaction. ▶ Methyl orange is degraded by CWPO with Al/Fe-PILCs at ambient conditions.

Keywords
Pillared clays; Azo dye methyl orange; Catalytic wet peroxide oxidation
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Effect of the atomic active metal ratio in Al/Fe-, Al/Cu- and Al/(Fe–Cu)-intercalating solutions on the physicochemical properties and catalytic activity of pillared clays in the CWPO of methyl orange
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 100, Issues 1–2, 11 October 2010, Pages 271–281
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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Any Questions? feel free to contact us