MgAl-Layered double hydroxides (MgAl-LDH), which is a kind of lamellar ionic compound composed of positively charged host layer and exchangeable anion in the gallery, has been exploited to use in environmental remediation, catalysis, drug delivery, fire retardant, and CO2 capture. However, conventional preparation methods for MgAl-LDH suffer from time-consuming aging or hydrothermal treatment, agglomeration, and low purity. Herein, we report a rapid and facile method to prepare MgAl-LDH with high purity and crystallinity using magnesium oxide (MgO) and sodium aluminate (NaAlO2) via a dissolution-reprecipitation (DR) process. During the DR process, the Mg2+ and OH- released from MgO immediately react with Al(OH)4- to nucleate and grow into high-crystallinity MgAl-LDH at the interfacial boundary of MgO, avoiding time-consuming aging or hydrothermal treatment to eliminate the impurity phase and amorphous phase. The as-prepared MgAl-LDH maintained the external profile of the pristine MgO and exhibited a narrow particle distribution, which provides a novel insight to prevent the agglomeration of MgAl-LDH and to control the particle size. Furthermore, this method is easy to scale up; the concentrated slurry (ca.20 wt%) with MgO and NaAlO2 still can be employed to prepare MgAl-LDH under a mild condition. The DR process of MgO not only gains a new understanding of the formation mechanism of MgAl-LDH but also can be used to tailor MgAl-LDH for application across a wide spectrum of areas.

Rapid synthesis of MgAl-layered double hydroxides with uniform particle size and high crystallinity via dissolution-reprecipitation of MgO

ACS Spring Meeting 2021

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