Adsorption of glutamic acid from aqueous solution with calcined layered double Mg-Fe-CO3 hydroxide
(School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)
Abstract: Layered double Mg-Fe-CO3 hydroxide (Mg-Fe-LDH) with a mole ratio of Mg to Fe of 3 was synthesized by coprecipitation method and calcined product Mg-Fe-CLDH was obtained by heating Mg-Fe-LDH at 500 °C for 6 h. The as prepared Mg-Fe-LDH and calcined Mg-Fe-CLDH were used for removal of glutamic acid (Glu) from aqueous solution, respectively. Batch studies were carried out to address various experimental parameters such as contact time, pH, initial glutamic acid (Glu) concentration, co-existing anions and temperature. Glu was removed effectively (99.9%) under the optimized experimental conditions with Mg-Fe-CLDH. The adsorption kinetics follows the Ho’s pseudo second-order model. Isotherms for adsorption with Mg-Fe-CLDH at different solution temperatures were well described using the Langmuir model with a good correlation coefficient. The intraparticle diffusion model fitted the data well, which suggests that the intraparticle diffusion is not only the rate-limiting step.
Key words: calcined layered double hydroxides; glutamic acid; adsorption