Preparation of Mg–Al layered double hydroxide doped with Fe2+ and its application to Cr(VI) removal

Kinetics of Cr(VI) removal by Mg–Al layered double hydroxide doped with Fe2+

“…For example, Zr 4+ -substituted ZnAl/MgAl-layered double hydroxides improved the adsorption of Cr(VI) and Se(IV) from aqueous solutions [5]. We previously reported that an Fe 2+ -doped Mg-Al LDH removed Cr(VI) from aqueous solution through the anion exchange of Cr 2 O 7 2− with intercalated Cl − , the production of Cr(OH) 3 , and the adsorption of Cr 2 O 7 2− on the surface of the produced FeO(OH) [6]. The excellent performance of this LDH for Cr(VI) removal resulted from both the anion exchange properties of Mg-Al LDH and the reducing activity of the Fe 2+ doped into the Mg-Al LDH.…”

Synthesis of novel CO 3 2− /Cl − -bearing 3(Mg + Zn)/(Al + Fe) layered double hydroxides for the removal of anionic hazards

“…Cr(VI) as well as some of the residual dyes are 14 non-biodegradable owing to their complex molecular structures, 15 especially the case of heavy metal complex dyes, which make them 16 more stable and resistant to bio-degradation [3,4] and photo- 17 degradation a swell [5]. Many of these complex compounds are also 18 toxic in nature and can cause direct destruction or affect capabilities 19 of various living organisms [6].…”

Equilibrium and kinetics studies on As(V) and Sb(V) removal by Fe2+-doped Mg–Al layered double hydroxides

“…Fe 2þ -doped MgeAl LDH can take up AsO 4 3À and SbðOHÞ 6 À from an aqueous solution due to anion exchange with Cl À intercalated in the LDH interlayer. During the reaction, Fe 2þ doped in the MgeAl LDH host layer is oxidized to Fe 3þ (Kameda et al, 2014). This increases the charge of the positive layer in the LDH, increasing the anion-uptake capacity because of the strong electrostatic force between the positive layer and the anion.…”

“…Fe 2þ -doped MgeAl LDH was prepared by the dropwise addition of a MgeFeeAl chloride solution to aqueous NaOH at constant pH, as was described in our previous paper (Kameda et al, 2014). Fe 2þ -doped MgeAl LDH contained 16.6 wt% Mg 2þ , 6.3 wt% Al 3þ , 8.7 wt% Fe 2þ , and 4.4 wt% Fe 3þ .…”

“…In a previous study, MgeAl LDHs doped with Fe 2þ were prepared by coprecipitation, and they were then used to remove Cr(VI) from an aqueous solution (Kameda et al, 2014). The doping replaced some of the Mg 2þ in the LDH host layer with Fe 2þ .…”