Synthesis of Mg – Fe layered double hydroxides for the removal of various pollutants from wastewater

Abstract

In this thesis, an innovative Layered double hydroxide (LDH) and calcined layered double hydroxide (C-LDH) nanoparticles are synthesized by the sol-gel method using CTAB as shape and pore directing agent for adsorption of indigo carmine dye (IC) from aqueous solution as an anionic dye in a batch system. The physicochemical features were monitored by X-ray diffraction (XRD), Fourier transformer infra-red (FTIR), N2 adsorption-desorption isotherm, Field emission electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). Calcined and non-calcined LDHs were used as adsorbents to remove indigo carmine dye from an aqueous solution. Via follow up the reaction parameters including contact time, initial dye concentration, pH and temperature investigated. The adsorption kinetics were studied using classic equations of pseudo-first-order, second-order and intra-particle diffusion models. The dynamical data fits well with the pseudo-second order kinetic model. The positive value of the changes in enthalpy (∆H◦) and the negative value of Gibbs free energy (∆G◦), explored that the adsorption is endothermic and spontaneous at all the studied temperatures. The results indicated that LDH nanoparticles conserved a good activity even after five consecutive cycle of reuse. This demonstrates that LDH and C-LDH nanoparticles are considered as potential novel adsorbents for remediation of wastewater containing IC.