Decolorization of Methylene Blue from Aqueous Solution Using Mg-Fe-Al Layered Double Hydroxides with H2O2

Abstract

Layered double hydroxides (LDH) or hydrotalcite, also classified to the type of anionic clays, are basic solid materials formed by divalent metal cation hydroxide layers with the brucite structure 1,2 .Layered double hydroxides (LDH) or hydrotalcite, also classified to the type of anionic clays, are basic solid materials formed by divalent metal cation hydroxide layers with the brucite structure 1,2 . The layers contain metal ions of at least two different oxidation states. The most common case of diand trivalent cations leads to the general chemical formulawhere x refers to the M 3+ /(M 2+ + M 3+ ) ratio ranging between 0.25 and 0.4. Due to the replacement of Mg 2+ by a trivalent ion, the network would not balance the charge and appear a positively charge in the brucite sheet. Therefore, anions A nlike carbonate, sulfate, phosphate, nitrate, chloride, etc. are intercalated in the interlayer section of the clay structure 1,3,4 . By this way, a large number of layered double hydroxides were prepared by changes in the ratio of Mg 2+ /M 3+ or the exchanges of anions. These derived hydrotalcites are designed for the adaptation of the application purposes [2][3][4][5][6][7][8][9] . For some typical examples, Mg-Al-CO3 like hydrotalcites was used as basic catalysts for the Hantzsch pyridine synthesis 3 , aldol condensation 4,5 . Mg-Al-molybdate layered double hydroxide prepared by the exchange of anion carbonates with molybdate is an active catalyst for dehydro-

Photo-Fenton abatement of aqueous organics using metal-organic frameworks: An advancement from benchmark zeolite

“…(2017) reported that 125 mg L -1 AgNPs composites derived from waste tea extract removed approximately 74% of low-concentration MB (0.008 mM) within 50 min at pH 7.5 in the presence of 294 mM H2O2. In Thao & Trang (2013), high concentration of MB (9.4 mM) was degraded by 80% after 50 min using a large amount of catalyst (1000 mg L -1 ) and high H2O2 concentration (132 mM). MnO2-templeted Fe oxide-coated diatomite at dose of 100 mg L -1 exhibited the photodegradation efficiency of 77.5% at 0.06 mM MB under UV irradiation for 120 min using relatively high H2O2 concentration (90 mM).…”

Effective Removal and Mineralization of 8‐Hydroxyquinoline‐5‐sulfonic Acid through a Pressurized Electro‐Fenton‐like Process with Ni−Cu−Al Layered Double Hydroxide

“…LDH is a cheap hydrotalcite‐like compound, characterized by a 2D flat network structure with a formula [M 1‐x 2+ M x 3+ (OH − ) 2 ] x+ (A n− ) x/n mH 2 O in which M 2+ and M 3+ refers to metal cations, such as Mg 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , and Al 3+ , Fe 3+ , Cr 3+ , Co 3+ , respectively, and A n− represents organic or inorganic inter layer anions . In the last years, LDHs based catalysts were proposed for many environmental applications, including catalytic wet peroxide oxidation and catalytic ozonation, Fenton and Fenton‐like processes as well as photo‐Fenton . It has been reported that LDHs exhibited good performances for Fenton‐like reactions due to strong metal synergic interactions and low metal leaching compared to other solid catalysts .…”