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Lithium/aluminum layered double hydroxides (Li/Al-LDHs) were synthesized via a facile hydrothermal route, using lithium and aluminum chloride mixed solutions with various molar ratios (Li + /Al 3+ ¼ 2, 3, 4, 5) as precursors and urea as a precipitating agent. The structure, morphology, and textural properties of the calcined Li/Al-LDHs (Li/Al-CLDHs) were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and nitrogen adsorption-desorption. It was found that the threedimensional petal-like Li/Al-CLDHs assemblies were constructed from hexagonal nanosheets with different sizes. The Li/Al-CLDHs contain three types of hierarchical porous organization such as small mesopores (ca. 4.5-10 nm), large mesopores (ca. 40-50 nm) and macropores (ca. 200-500 nm). The asprepared Li/Al-CLDHs samples exhibit excellent adsorption capacity of 158.7 mg g À1 towards fluoride species in water. Thermodynamic and kinetic studies revealed that the adsorption process was spontaneous and endothermic in nature. Analyses by X-ray photoelectron spectroscopy confirmed that fluoride is distributed in the layer channel by ion exchange, physical adsorption as well as insertion into the host layer lattice during the rehydration process. The superior sorption capacity of Li/Al-CLDHs is attributed to the unique hierarchically porous structures and high specific surface areas.

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Hollow microspheres of hierarchical ZnAl-layered double hydroxides (LDHs) were synthesized by a simple hydrothermal method using hexamethylenetetramine as precipitating agent, sodium dodecyl benzene sulphonate (SDBS) as surfactant and sodium tartrate, sodium citrate and sodium salicylate (SS) as structure-directing agents, respectively. Characterization results of the microspheres synthesized indicate that the modified ZnAl-LDHs formed a variety of morphologies, surface areas and pore volumes. The hierarchical porous ZnAl/SDBS-LDH prepared using SS possesses the highest surface area (128.9 m 2 /g) and the greatest pore volume (0.37 cm 3 /g). A possible formation mechanism of the special three-dimensional nanostructures from the primary LDH nanosheet building units is proposed on the basis of the interaction between SS molecules and LDH crystals. The size of the channel height is approximately equal to the diameter of the intercalated anion SDBS, indicating that SDBS is in a vertical single-layer arrangement. Using p-nitrophenol as model pollutant, the effects of initial concentration of p-nitrophenol and contact time on the adsorption of p-nitrophenol using various ZnAl-LDHs were investigated by performing a series of experiments. Results of these experiments indicate that the microsphere hydrophobic ZnAl/SDBS-LDH modified using SS has a maximum p-nitrophenol adsorption capacity of 101.6 mg/g.

Indium tin oxide (ITO) nanopowders with high crystalline were synthesized by a simple solvothermal method with isopropanol as the selected solvent. X-ray diffraction was employed to characterize the crystal structure and crystalline size while the effect of the reaction time on morphologies was studied by FE-SEM. The results revealed that, with the increase of solvothermal time, the morphologies were evolved gradually from porous plates with high specific surface area to rods with narrow diameter distribution. The solvothermal time has little effect on crystalline size, which is 18nm approximately for all the samples. With the increase of solvothermal time, the electric conductivity decreases slightly first and then increases greatly. The possible mechanisms for the effect of solvothermal time on ITO powder morphologies and electric conductivity are proposed.