Assessing the effect of calcination on adsorption capability of Mg/Al layer double hydroxides (LDHs)

The present study was carried out to prepare and characterize calcined Mg/Al layer double hydroxides (LDHs) used in the adsorption of methyl orange in an aqueous solution as an anionic dye in a batch system. Synthesis of LDHs using coprecipitation method with Mg/Al ratio of 3:1 and obtained material was treated by hydrothermal treatment for 4 h in 400 degrees C. The result showed that hydrothermal treatment on the synthesis of Mg/Al LDHs yielded the formation of mixed metal oxide from magnesium oxide and aluminum oxide on calcined LDHs were shown on a wide diffraction pattern, while infrared spectrum showed that NO3 (-) and CO3 (2-) as balancing anions disappeared after calcination process. The optimum condition for calcined layer double hydroxides (CLDH) and LDHs were in pH 4 (40.61 mg g(-1)) and pH 3 (36.29 mg g(-1)) for methyl orange adsorption. The equilibrium time for CLDH and LDHs respectively were 3 h and 5 h where the initial time started rapidly. The kinetic study described pseudo-second-order fitted for methyl orange adsorption with R-2 = 0.9998 and 0.9996 for CLDH and LDH. The best isotherm was shown by Freundlich model with R-2 = 0.9957 and 0.9721 for CLDH and LDH and. The results suggested that calcined LDHs were efficient adsorbents for methyl orange remediation of relatively high concentrations.

Automated summary

The present study aimed to prepare and characterize calcined Mg/Al layer double hydroxides (LDHs) for the adsorption of methyl orange in a batch system. The results showed that calcined LDHs were efficient adsorbents for the remediation of methyl orange at relatively high concentrations.