Synthesis and Application of Layered Double Hydroxide for the removal of Copper in Wastewater

Abstract

Ni-Al Layered double hydroxide (Ni-Al LDHs) with M²⁺: M³⁺ (4:1) ratio was synthesized by co-precipitation method from nitrate salt solutions. The layered double hydroxide was characterized by Fourier transform infrared spectroscopy, X-Ray Diffraction, Energy Dispersive Spectroscopy/Scanning Electronic Microscopy. The influences of phase contact time, temperature and initial concentrations were investigated to optimize the conditions for maximum adsorption. The experimental data were analyzed by Langmuir and Freundlich isotherm models and fitted well with correlation coefficient values of 0.9996 and 0.9995 respectively.  The thermodynamic parameters of Isosteric heat of adsorption (DH_x), Activation energy (E_a), Enthalpy change (DH^o) and Entropy change (DS^o) were calculated to be 18.1KJ/mol, 1.447KJ/mol, -7.135J/mol and 24J/molK respectively. The results shows that the adsorption process was spontaneous and exothermic.