Calcium Iron Layered Double Hydroxide/Poly(vinyl chloride) Nanocomposites: Synthesis, Characterization and Cd2+ Removal Behavior

Poly(vinyl chloride) (PVC) and other thermoplastics have received more attention in the last decades due to their high fire resistance, hydrophobicity, and flexibility. To improve the thermal stability of these classes of polymers, heat stabilizers should be used. Layered double hydroxides (LDHs) are a green and inexpensive class of heat stabilizers. In this study at first, the co-precipitation method was used to prepare nanostructure calcium/iron layered double hydroxide (Ca/Fe-LDH), and then it was organo-modified with citrate as a green and environmentally friendly anion. In the next step, it was used as a nanofiller for improving the thermal properties of the PVC matrix. Accordingly, LDH-Cit/PVC nanocomposites (NCs) with different amounts of LDH-Cit (5, 10 and 15 wt%) were synthesis by ultrasonic irradiation technique. The structural, morphological, and thermal properties of the synthesized NCs were evaluated with XRD, FT-IR, FE-SEM, TGA techniques. By introducing of LDH-Cit in the NCs, the residue at 800 degrees C was increased from 10 to 23% compared to pure PVC. The NCs ability to removing Cd2+ metal ion and the effects of time, pH, and Cd2+ concentration on the removal efficiency of Cd2+ were studied. Due to the increase of the adsorbent mass and removal efficiency of Cd2+, the 60 mg L-1 of Cd2+ concentration and pH of 7 were chosen as the optimized condition. Also, kinetics studies on the experimental data for adsorbents showed acceptable adaptation with the Langmuir isotherm and pseudo-second-order kinetic model.