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

Abstract

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 hours in 400 °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) and pH 3 (36.29 mg/g) for methyl orange adsorption. The equilibrium time for CLDH and LDHs respectively were 3 hours and 5 hours where the initial time started rapidly. The kinetic study described pseudo-second-order fitted for methyl orange adsorption with R2 = 0.9998 and 0.9996 for CLDH and LDH. The best isotherm was shown by Freundlich model with R2 = 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.

Reusable Catalyst of KF/Mg-Al Layered Double for Biodiesel Conversion and Optimization using Bohn-Behnken Design

“…Figure 2 exhibits the reflections of LDH and KF/LDH. It is seen that both samples show the characteristic peaks of (003), ( 006), (009), (015), ( 018), (110), and (113) that are associated with LDH structure [9,10,13]. It is no disappeared peak after modification with KF, moreover, there are two additional peaks at around 19.8 o and 45.6 o corresponding to the presence of KF [14].…”