Hierarchically Porous Zn/Al Layered Double Hydroxides Intercalated with Citrate and Their Adsorption toward Parachlorophenol in Water.

A simple synthesis route is reported for generation of hierarchically porous Zn/Al layered double hydroxides (LDHs) by using urea and trisodium citrate (TSC) as precipitating agent and structure-directing agent, respectively. The structure, morphology and textural properties of the as-prepared LDH solids were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption-desorption techniques. It was found that the flowerlike Zn/Al-LDHs hierarchically porous assemblies were constructed from hexagonal nanosheets with different sizes. Pseudo-second-order kinetic model was turn out to fit the experimental data well. The adsorption data were better described using the Langmuir adsorption isotherm with excellent adsorption capacity of 98.7 mg/g towards parachlorophenol in water. [ABSTRACT FROM PUBLISHER]