Electrospun Polystyrene/LDH Fibrous Membranes for the Removal of Cd²⁺ Ions

Layered double hydroxides (LDHs) have been extensively studied for a broad range of applications because of their ease of synthesis and chemical modifications. The chemical and crystal structure of LDH provides opportunities of combination with polymers forming nanocomposites. In the current study, MgAl-LDH particulates have been incorporated into micro- and nanofibers of polystyrene (PS) using an electrospinning processing technique of their respective homogeneous solutions. The effect of the varying proportions of LDH and PS on the structure, morphology, and thermal properties of the fabricated LDH-PS fibrous membranes has been investigated. The potential application of the optimally fabricated LDH-PS fibrous membranes in the removal of Cd²⁺ ions from aqueous media has been evaluated as well. Results showed the possibility of loading the PS fibrous membranes with up to 60 wt% of LDH particulates, which in turn modified the thermal stability and integrity of the produced fibrous membranes. Due to the high hydrophobicity of the PS fibrous matrix, no changes in the crystal structure of the LDH inclusions were observed. Both as-prepared LDH particulates and optimally prepared LDH-PS fibrous membranes showed a high potential for the removal of Cd²⁺ ions from aqueous media. This is attributed to a cation-exchange mechanism involving the adsorption of Cd²⁺ ions from a solution with the preferential leakage of Al³⁺ ions from the crystal structure of LDH.