Intercalation of Anthraquinone-2-Sulphonate into Magnesium-Aluminum Layered Double Hydroxide and its Calcined Products by Ion Exchange and Memory Effect Properties
M.Z.b. Hussein, A.H. Yahaya, M. Ibrahim, M. Tahir and H. Sulimat
Multifunctional Nanomaterials for Industrial Application (MULIA) Research Group,
Department of Chemistry, Universiti Putra Malaysia, 43400UPM, Serdang, Selangor, Malaysia
Layered double hydroxide of Mg-Al-nitrate system (LDH) was prepared and its heat-treated products (LDHTs) were obtained by calcining the LDH at 250 - 750°C, for 5 hours at atmospheric condition. The LDH and the LDHTs were used as an inorganic host for the intercalation of AQ2 via ion exchange or memory effect property by exposing the LDH and LDHTs in aqueous solution containing an anion, anthraquinone-2-sulfonate (AQ2) for the formation of an organic-inorganic layered nanohybrid materials. X-ray diffractograms showed that the layered structure of LDH collapsed when it was heated at around 350°C, and an oxide phase, MgAl2O4 appeared. Due to the memory effect property, the regeneration of LDH from LDHT was observed and at the same time the AQ2 was intercalated when LDHT was treated with the aqueous solution containing AQ2. As a result, formation of an organic-inorganic layered nanohybrid material was also observed. Similarly, the same material can be formed by ion exchange of LDH with AQ2. The basal spacing of LDH was found expanded from 8.1 Е to around 20 Е in the resulting nanohybrid. This is to accommodate a bigger size of the AQ2 moiety with specific orientation inside the interlamella of the inorganic layered structure that warrants the layer expansion. Incomplete intercalation and ion exchange process resulted in a mixed LDH and a nanohybrid phase as observed in the PXRD pattern of the resulting material.