Using the “memory effect” of hydrotalcites for improving the catalytic reduction of nitrates in water

Chemical denitrification of water by zero-valent magnesium powder

“…Luk and Au-Yeung [22] had reported 41.5% NO 3 − -N, 1.3% NO 2 − -N and 2.5% NH 4 + -N, with TN removal of 55% from initial nitrate-N concentration of 20 mg/L at Al:NO 3 − -N molar ratio 7.8. For comparison, in a study on catalytic nitrate reduction by palladium catalyst on Cu/Mg/Al hydrocalcites reported 23% NH 4 + -N fraction after 200 min of reaction from initial NO 3 − -N concentration of 20.3 mg/L [33]. Present results show that end products of nitrate reduction may be either nitrite, or ammonia or various gaseous species like N 2 and these distribution largely depends on initial NO 3 − -N concentration and Mg 0 dose.…”

Nitrate sorption by thermally activated Mg/Al chloride hydrotalcite-like compound

“…Hydrotalcite-like compounds constitute an important class of inorganic materials with desirable properties to remove anionic pollutants from water [24][25][26][27][28]. Hydrotalcites, also known as layered double hydroxides (LDHs) or ionic clays are based upon the brucite [Mg(OH) 2 ] structure in which some of the divalent cations are replaced by trivalent cations (e.g., Al, Fe, Cr etc.)…”

Synthesis and intracrystalline oxidation of nitrite-intercalated layered double hydroxides

“…We chose nitrite as the interlayer anion in this work for two reasons. Firstly no nitrite-LDHs have been reported so far though these have been observed as intermediates when nitrate ions were reduced using LDH-supported Pd/Cu catalysts [24,25]. Secondly the nitrite anion can be oxidized easily to nitrate under mild conditions.…”