Removal of cadmium ions from aqueous solutions using TMU-16-NH2 metal organic framework

Abstract In this research, removal of cadmium from aqueous samples by TMU-16-NH 2 metal–organic framework was investigated. In a batch process method, the effect of pH, initial concentration, contact time, temperature and sorbent weight on sorption process was studied. Equilibrium isotherms were fitted by Langmuir and Freundlich equations. The maximum adsorption capacity of Cd(II) was determined 126.6 mg g −1 . The metal–organic framework was successfully applied to the quick extraction of trace amounts of Cd(II) ions in water samples. The maximum removal percentage was obtained 98.91 at pH 6.0 and 30 min contact time. The Gibbs free energy ‎(ΔG 0 ‎), the enthalpy (ΔH 0 ), and the entropy (ΔS 0 ) were also calculated from thermodynamic studies. ‎The positive values of ΔH 0 , ΔS 0 and the negative value of ΔG 0 , confirmed the endothermic nature, randomness and spontaneity of adsorption process.