Regeneration mechanism, modification strategy, and environment application of layered double hydroxides: Insights based on memory effect

2022 ◽  
Vol 450 ◽  
pp. 214253
Author(s):  
Haoyang Ye ◽  
Shiyu Liu ◽  
Deyou Yu ◽  
Xuerong Zhou ◽  
Lei Qin ◽  
...  
Keyword(s):  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Regeneration Mechanism ◽  
Double Hydroxides

scholarly journals Luminescent Layered Double Hydroxides Intercalated with an Anionic Photosensitizer via the Memory Effect

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 153 ◽  
Author(s):  
Alexandre Teixeira ◽  
Alysson Morais ◽  
Ivan Silva ◽  
Eric Breynaert ◽  
Danilo Mustafa
Keyword(s):  
Aqueous Solution ◽  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Efficient Energy Transfer ◽  
Efficient Energy ◽  
Calcination Temperatures ◽  
Anionic Species ◽  
Benzenetricarboxylic Acid ◽  
Double Hydroxides ◽  
Rehydration Process

Layered double hydroxides (LDHs) containing Eu3+ activators were synthesized by coprecipitation of Zn2+, Al3+, and Eu3+ in alkaline NO3−-rich aqueous solution. Upon calcination, these materials transform into a crystalline ZnO solid solution containing Al and Eu. For suitably low calcination temperatures, this phase can be restored to LDH by rehydration in water, a feature known as the memory effect. During rehydration of an LDH, new anionic species can be intercalated and functionalized, obtaining desired physicochemical properties. This work explores the memory effect as a route to produce luminescent LDHs intercalated with 1,3,5-benzenetricarboxylic acid (BTC), a known anionic photosensitizer for Eu3+. Time-dependent hydration of calcined LDHs in a BTC-rich aqueous solution resulted in the recovery of the lamellar phase and in the intercalation with BTC. The interaction of this photosensitizer with Eu3+ in the recovered hydroxide layers gave rise to efficient energy transfer from the BTC antennae to the Eu3+ ions, providing a useful tool to monitor the rehydration process of the calcined LDHs.

Phosphorus removal by hydrotalcite-like compounds (HTLcs)

1996 ◽  
Vol 34 (1-2) ◽  
pp. 161-168 ◽  
Author(s):  
Shin Hang-Sik ◽  
Kim Mi-Joo ◽  
Nam Se-Yong ◽  
Moon Hi-Chung
Keyword(s):  
Clay Minerals ◽  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Phosphorus Removal ◽  
Phosphate Uptake ◽  
Exchange Capacity ◽  
Uptake Capacity ◽  
Anionic Clay ◽  
Interlayer Anion ◽  
Double Hydroxides

Hydrotalcite-like compounds (HTLCs), which are also called anionic clay minerals or Layered Double Hydroxides (LDHs), can be formulated by M(II)1−xM(III)X(OH)2(An−)X/nyH2O. This chemical, which has anoin exchange capacity, could be an alternative chemical for phosphorus removal. The phosphate uptake by HTLcs containing C1− as the interlayer anion was found to be 2.35-2.83 meq of P/g. The most serious obstacle anion against phosphate uptake was bicarbonate because the selectivity of carbonate by LDH is the highest. To investigate the possibility of LDH's recycle employing the “Memory effect”, calcined LDH (CLDH) was repeatedly used for 6 times. From the fifth time, the final phosphate uptake capacity decreased. The consecutive reconstruction mechanism of CLDH is not yet known but it is certain that the possibility of LDH's recycle is promising.

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