Uptake of Nd³⁺ and Sr²⁺ by Li–Al layered double hydroxide intercalated with triethylenetetramine-hexaacetic acid: kinetic and equilibrium studies

Abstract

Li–Al layered double hydroxide intercalated with triethylenetetramine-hexaacetic acid (TTHA) was found to take up Nd3+ ions preferentially over Sr2+ ions from solutions, due to the difference in the stabilities of the Nd–TTHA and Sr–TTHA complexes.

Kinetic and equilibrium studies on the uptake of Nd3+ and Sr2+ by Li–Al layered double hydroxide intercalated with 1-hydroxyethane-1,1-diphosphonic acid

“…4 and 5, the Sr 2+ uptake by HEDPÁLi-Al LDH was larger than the Nd 3+ uptake under all conditions, although the Nd 3+ uptake by TTHAÁLi-Al LDH was superior to the Sr 2+ uptake [11]. This is attributed to the difference in the number of ligands, which is required for the uptake of Nd 3+ or Sr 2+ .…”

“…It may be stated that HEDPÁLi-Al LDH preferentially takes up Sr 2+ rather than Nd 3+ . As mentioned above, the Nd 3+ uptake by TTHAÁLi-Al LDH was superior to the Sr 2+ uptake [11]. The HEDPÁLi-Al LDH is dissimilar from TTHAÁLi-Al LDH for the preferential removal of metal ions.…”

“…2 shows the XRD patterns of (a) NO 3 ÁLi-Al LDH and HEDPÁLi-Al LDH. As shown in our previous paper [11], the XRD peaks observed for NO 3 ÁLi-Al LDH (Fig. 2a) were attributed to lithium aluminum nitrate hydroxide hydrate (JCPDS card No.…”

“…This suspension was filtered and washed repeatedly with deionized water to neutral pH to finally obtain HEDPÁLi-Al LDH. Then, under reduced pressure (133 Pa), the product was dried for 40 h. NO 3 ÁLi-Al LDH was also synthesized by co-precipitation, as described in our previous paper [11].…”

Functionalized layered double hydroxide applied to heavy metal ions absorption: A review

“…For example, LiAl-LDH intercalated with triethylenetetramine was used to absorb Nd 3+ and Sr 2+ . Due to the poor stability of Li metal chelate, the Li-Al LDH has free triethylenetetramine ions in the interlayer, which can effectively improve its heavy-metal-ion-absorption capacity [35].…”