Intercalation of $$\hbox {LDH NO}_{{3}}$$ LDH NO 3 with short-chain intercalants

Abstract

Intercalation behaviour of layered-double hydroxide (LDH) with short-chain intercalants (\({-}(\hbox {CH}_{2})_{n}{-}, n<9\)) is significantly difficult and less reported than with long-chain intercalants. The present study reports an efficient way to intercalate LDH with short-chain intercalants (\(n=4\) and 8) and investigates the effect of layer charge on intercalation behaviour of LDHs. Short-chain anionic surfactants were successfully intercalated with synthetic LDHs \([\hbox {Zn}_{1-x}\hbox {Al}_{x}(\hbox {OH})_{2}\hbox {NO}_{{3}}{\cdot } n\hbox {H}_{2}\hbox {O},\,x=0.2{-}0.33]\) by an ion-exchange intercalation technique in a slightly acidic medium (\(\hbox {pH}=5.4\)). The adverse effect of a carbonate anion was avoided by performing the ion-exchange intercalation in slightly acidic medium (\(\hbox {pH}=5.4\)). It was found that basal spacing \((d_{003})\) and experimental organic loading of intercalated LDH (O-LDH) increase monotonically with increasing anion-exchange capacity of LDH and intercalant chain length. The evolution of intercalated LDH (O-LDH) structures with increasing intercalant chain length and layered charge has been deciphered by correlating basal spacing of O-LDHs (by X-ray powder diffraction), organic loading data (by thermogravimetric analysis) and molecular conformation of O-LDHs (by Fourier-transform infrared spectroscopy) within the LDH gallery. Successful intercalation of LDH with these short-chain intercalants in slightly acidic medium has not been reported previously.