Interlayer Structures and Dynamics of Arsenate and Arsenite Intercalated Layered Double Hydroxides: A First Principles Study

Abstract

Abstract:In this study, by using first principles simulation techniques, we explored the basal spacings, interlayer structures, and dynamics of arsenite and arsenate intercalated Layered double hydroxides (LDHs). Our results confirm that the basal spacings of NO 3 − -LDHs increase with layer charge densities. It is found that Arsenic (As) species can enter the gallery spaces of LDHs with a Mg/Al ratio of 2:1 but they cannot enter those with lower charge densities. Interlayer species show layering distributions. All anions form a single layer distribution while water molecules form a single layer distribution at low layer charge density and a double layer distribution at high layer charge densities. H 2 AsO 4 − has two orientations in the interlayer regions (i.e., one with its three folds axis normal to the layer sheets and another with its two folds axis normal to the layer sheets), and only the latter is observed for HAsO 4 2− . H 2 AsO 3 − orientates in a tilt-lying way. The mobility of water and NO 3 − increases with the layer charge densities while As species have very low mobility.Our simulations provide microscopic information of As intercalated LDHs, which can be used for further understanding of the structures of oxy-anion intercalated LDHs.

Luminescent sensing film based on sulfosalicylic acid modified Tb(III)-doped yttrium hydroxide nanosheets

“…Lanthanides nanomaterials and complexes play an important role in inorganic chemistry and materials science, because of their unique spectral characteristics and 4f electron orbits shielded by 5s 2 and 5p 6 shells [1]. The lanthanide ions have a large Stokes shift and show strong, pure, long life and narrow emission bands [2].…”

Gadolinium-Doped Gallic Acid-Zinc/Aluminium-Layered Double Hydroxide/Gold Theranostic Nanoparticles for a Bimodal Magnetic Resonance Imaging and Drug Delivery System

“…Zn/Al-layered double hydroxide (LDH) is one of the candidates capable of simultaneously intercalating and adsorbing theranostic agents due to their exchangeable interlayer anions. LDH is one of the group of two-dimensional layered structures materials [ 13 ] and has the general formula of [ (OH) 2 ] x + [A n − ] x / n · m H 2 O] [ 14 ], where divalent and trivalent metal cations are represented by M 2+ and M 3+ , respectively, and interlayer exchangeable anions are represented by [A n − ], and water as x / n [ 8 , 15 , 16 , 17 ]. Gallic acid is the therapeutic agent employed in this research; it is a naturally occurring polyhydroxyl phenolic compound, often found in different kinds of fruits.…”