Utilization of Calcined Ni-Al Layered Double Hydroxide (LDH) as an Adsorbent for Removal of Methyl Orange Dye from Aqueous Solution

In the present work, Ni-Al layered double hydroxide (Ni-Al LDH) was synthesized by coprecipitation method from their nitrate salts and utilized as an adsorbent for the removal of methyl orange (MO) dye from its aqueous solution. The synthesized Ni-Al LDH was characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), and N-2 adsorption-desorption analysis. Batch adsorption isotherm experiments were conducted with methyl orange dye at three different temperatures (30, 40, and 50 degrees C). Adsorption isotherm data were fitted with Langmuir, Freundlich, and Redlich-Peterson models. It was found that the Langmuir and Redlich-Peterson isotherm models best described the adsorption of MO on calcined Ni-Al LDH. The experimental results revealed that the increase in temperature increases the adsorption capacity of MO on calcined Ni-Al LDH adsorbent. The maximum adsorption capacity was found to be 5.7 x 10(-4) mol g(-1) at 50 degrees C. The influence of pH on the adsorption of MO dye indicated that the adsorbent has good structural stability in the studied pH range. Thermodynamic studies authenticated that the adsorption of MO dye on calcined Ni-Al LDH was spontaneous, endothermic and entropy driven process. The results indicate that the calcined Ni-Al LDH can be employed as an adsorbent for removal of dye from aqueous solution. (c) 2013 American Institute of Chemical Engineers Environ Prog, 33: 154-159, 2014