4-Aminoacetophenone Intercalated CoAl Layered Double Hydroxides: Synthesis, Characterization and Adsorptive Removal of Cd(II) Ions from Water Samples

Abstract

In the present study, CoAl-NO₃ Layered Double Hydroxides (CoAl-NO₃-LDH) was synthesized and an enolate anion of 4-Aminoacetophenone (AAP) was intercalated into LDH following the reconstruction approach. The CoAl-NO₃-LDH and CoAl-AAP-LDH were characterized by Fourier-Transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analyses. CoAl-AAP-LDH worked well for adsorption of Cd(II) ions from aqueous samples at optimum pH 7, adsorbent dosage 25 mg, concentration of Cd(II) ions 25 mg L^-1 and shaking time 20 min at 25 °C. Different isotherms such as Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms fitted well to adsorption data with correlation coefficient (R²) of 0.998, 0.982 and 0.992, respectively. Monolayered (Q_m) and multi-layered (KF) capacities of CoAl-AAP-LDH for adsorption of Cd(II) ions were calculated and found to be 34.40 and 19.44 mg g^-1, respectively. Sorption energy was calculated and found to be 9.13 kJ mol^-1, indicating chemisorption or ion exchange sorption mechanism. The method worked well for the adsorption of Cd(II) ions from wastewater samples