Kinetic, isotherm, and mechanism investigations of the removal of nitrate and nitrite from water by the synthesized hydrotalcite Mg–Al

Potential Applicability of Mg/Al-Layered Double Hydroxide (LDH) for Environmentally Friendly Chromium-based Leather Tanning

“…However, it should be noted that the (003) crystal plane gradually increases as the Mg/Al ratio increased from 1:1 (Mg 1 Al 1 -LDH-8h) to 3:1 (Mg 3 Al 1 -LDH-8h), possibly due to the combined effects of electronegativity and cation radius of the starting metal ions on the charge density and interleaf distance c of the MgAl-LDH particles . As the Mg:Al ratio increased from 1:1 to 3:1, the interleaf distance c increased from 0.151 to 0.157 nm, accompanied by a decrease in charge density between sheets . Further, only a slight difference was observed in the intensity of the outgoing diffraction peak at 15.6° (003), which gradually increased with an increase in aging time due to the increased number of stacked MgAl-LDH layers …”

“…23 As the Mg:Al ratio increased from 1:1 to 3:1, the interleaf distance c increased from 0.151 to 0.157 nm, accompanied by a decrease in charge density between sheets. 20 Further, only a slight difference was observed in the intensity of the outgoing diffraction peak at 15.6°(003), which gradually increased with an increase in aging time due to the increased number of stacked MgAl-LDH layers. 23 FTIR Analysis.…”

“…Recently, hydrotalcite, a layered double hydroxide (LDH), has attracted research attention in the tanning process due to its tunable functionalities and surface properties. , It is a typical synthetic layered clay with flat two-dimensional (2D) structural networks made of hydroxyl layers of bi/trivalent metal cations with apparent positive charges. , Note that most LDH materials have tunable properties and can be used as adsorbents for metal ions, ion exchangers, and catalysts . Specifically, the unique lamellar structure of LDH and its interlayer anion exchangeability could improve the adsorption efficiency of Cr­(VI) anions (in the form of Cr 2 O 7 2– and HCrO 4 – ) from water. , By controlling the bi/trivalent metal molar ratio, the surface features of LDH materials could be tuned to improve their adsorption capacitance for heavy metals (e.g., Cr­(III)/(IV)) . The size of the LDH could also be adjusted to control the amount of chromium anions intercalated between positively charged layers .…”

“…18 Specifically, the unique lamellar structure of LDH and its interlayer anion exchangeability could improve the adsorption efficiency of Cr(VI) anions (in the form of Cr 2 O 7 2− and HCrO 4 − ) from water. 19,20 By controlling the bi/trivalent metal molar ratio, the surface features of LDH materials could be tuned to improve their adsorption capacitance for heavy metals (e.g., Cr(III)/(IV)). 21 The size of the LDH could also be adjusted to control the amount of chromium anions intercalated between positively charged layers.…”

Dyeing with Hydrotalcite Hybrid Nanoclays and Disperse, Basic and Direct Dyes

“…On the one hand, by studying and comparing the graphs in Figure 4, it is possible to analyse the differences that exist between the uncalcined hydrotalcite and how the peaks change after calcination. There are two very characteristic bands of the nanoadsorbent at 1361 cm −1 which are assigned to the carbonate group -CO 3 2− [42,43] and another one located in the range 3200-3600 cm −1 clearly centred at 3408 cm −1 and which is attributed to the stretching between the oxygen and hydrogen of the hydroxyl group -OH [27,41,43] of the water between the clay laminae. The vibrations produced by methylene CH 2 [44] can be seen in the peaks at 2850 and 2918 cm −1 .…”