Natural Micas Intercalated with Al2O3 and Modified with Transition Metals as Catalysts of the Selective Oxidation of Ammonia to Nitrogen

Abstract

Natural cationic layered clays-vermiculite and phlogopite-pretreated with acids were intercalated with alumina pillars. In next step, transition metals were deposited on the surface of pillared interlayer clays (PILC) by a liquid ion exchange method. The catalyst samples were characterized with respect to: composition (EPMA), structure (XRD), texture (BET), surface acidity (NH 3 -TPD) and coordination of deposited transition metals (UV-vis-DRS). The modified clays were tested in the role of catalyst for the selective oxidation of ammonia to nitrogen. In a series of the studied samples the best catalytic performance presented alumina pillared vermiculite modified with copper.

Copper based catalysts for the selective ammonia oxidation into nitrogen and water vapour—Recent trends and open challenges

“…Alumina pillared vermiculite and phlogopite modified with copper proved to be active and selective catalysts of ammonia oxidation [124]. Despite comparable copper loadings for both materials, higher activity could be achieved with vermiculites.…”

“…78,118,127,129] or aluminium modified materials [e.g. [122][123][124], zeolites [e.g. 28,109,111,118] or H3PW12O4 (12-tungstophosphoric acid) [179], because of their acidity, which is advantageous in capturing ammonia close to the active species dispersed on the support surface.…”

Vermiculite-based catalyts for oxidation of organic pollutants in water and wastewater

“…Upon Fe doping bands assigned to octahedral coordination become more intense and are shifted to higher wavelengths (250 nm). Increases also the intensity of bands about 360 nm related to small Fe x O y clusters and above 400 nm -bulk Fe 2 O 3 oxide (Chmielarz et al, 2008, Chmielarz et al, 2009 (H 2 O 2 decomposition and phenol oxidation using H 2 O 2 ) strongly depends on temperature. It was shown that samples doped with iron are active in decomposition of hydrogen peroxide (Fig.…”

Optical and electromagnetic characteristics of clay–iron oxide nanocomposites

“…The layered clays used for these purposes are kaolin, montmorillonite, attapulgite, mica, sericite, hydrotalcite, fluoromica, hectorite, and saponite, but one of the most commercially interesting clays is bentonite, belonging to a structural M. Parvinzadeh (&) Á S. Eslami Department of Textile, Islamic Azad University, Shahre Rey Branch, Tehran, Iran e-mail: mparvinzadeh@gmail.com Preparation of iron pillaring solution and synthesis of Fe-pillared clay Following a procedure similar to that reported by several researchers [23][24][25][26][27][28][29], an aqueous solution of 0.4 M Na 2 CO 3 was slowly added to the solution of 0.2 M iron(III) nitrate with vigorous stirring (ca. 1,200 revs/min).…”