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This study focuses on the synthesis of various nanocomposites with heterojunction structures, MgAl-LDH (LDH = Layered double hydroxides) hybrid with semiconductor such as MoO3 and CuO. These solids were synthesized by co-precipitation method at constant pH and have been characterized extensively using AAS, XRD, FTIR and TEM-EDX methods. The catalytic activity of nanocomposites was tested in the photocatalytic degradation under solar irradiation of emerging pollutants as the pharmaceutical metronidazole (MNZ).The experimental parameters, including initial MNZ concentration, the nature of oxide incorporate in the photocatalyst, catalyst loading were explored. All the synthesized samples showed high photocatalytic performances; the highest photocatalysis efficiency was achieved with the photocatalyst dose 1.5 g/L and initial MNZ concentration of 10 mg/L at neutral pH. The photocatalytic experimental results were fitted very well to the Langmuir-Hinshelwood model. From The obtained results the calcined Layered double hydroxides/semiconductors could be efficient for the photocatalytic process under solar irradiation of pharmaceuticals and may contribute in environmental remediation.

Due to the abundant use of anionic surfactants in our life and their disposal in the environment, the removal of surfactants from waste water becomes necessary. The present study focused to the synthesis and application of layered double hydroxides and their derived oxides to remove the anionic surfactant, sodium dodecyl sulphate (SDS), from aqueous solution by adsorption and photocatalytic degradation under UV irradiation. The influencing of Zn 2+ /Al 3+ molar ratio and initial SDS concentration on the adsorption and photocatalytic degradation of SDS are studied and optimized. The obtained adsorption data were correlated with Langmuir and Freundlich isotherms models. Equilibrium studies indicated that the SDS removal obeyed Langmuir type of adsorption. Kinetic data were better described by pseudo-second-order model. The photocatalytic degradation of SDS has been found to fit the firstorder kinetics according to the Langmuir-Hinshelwood model.