Synthesis of Ni/Al layered double hydroxides (LDHs) for adsorption of malachite green and direct yellow dyes from solutions: Kinetic and thermodynamic

Ni/Al layered double hydroxides (LDHs) was synthesized by co-precipitation method at constant pH and characterized using XRD and FTIR analyses. Ni/Al LDHs was applied as adsorbent to removal malachite green and direct yellow in aqueous solution. The results show direct yellow more effective adsorbed than malachite green because LDHs has positive charges. Kinetics study showed that the adsorption process is more fits with PSO than PFO based on correlation coefficients. The adsorption process is describe by Freundlich isotherm models for all dyes. The value of enthalphy and entrophy shows that the adsorption process was endothermic and negative free energy value was indicated that the process was spontaneous.