Synthesis and characterisation of surfactant enhanced Mg–Al hydrotalcite-like compounds as potential 2-chlorophenol scavengers

Abstract

Magnesium aluminium hydroxycarbonate hydrotalcites (denoted as MgAl–CO3-HTs) with different Mg/Al molar ratios (4, 3 and 2) were synthesised by the co-precipitation method under low supersaturation conditions, and then treated with sodium dodecylsulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS) surfactants to produce the nanocomposites — organo-hydrotalcites; dodecylsulfate-hydrotalcites(DS-HTs) and dodecylbenzenesulfonate-hydrotalcites (DBS-HTs) through calcination-reconstruction method. Powder X-ray diffraction (PXRD) and infrared spectroscopy analysis of intercalated samples showed that dodecylsulfate and dodecylbenzenesulfonate guests were successfully intercalated into the parent hydrotalcites, with the PXRD revealing that the species could assume varying configurations within the interlayer gallery regions of this clay based materials, displaying monolayer and bilayer orientations.The uptake ability of the resulting DS-hydrotalcites and DBS-hydrotalcites for the adsorption of phenolic compounds from aqueous solution was investigated. The results showed that, the adsorption process can be described by pseudo-second order kinetics, while the capacity of 2-chlorophenol uptake is dependent on the MgII:AlIII ratio within the interlamellar of the organo-hydrotalcite, the anion present (with DBS modified samples showing higher adsorption capacities) and the pH at which adsorption was carried out.