Production and characterisation of LDH meixnerite powders

Abstract

Meixnerite, which is a magnesium-aluminium hydrotalcite compound, is a hydrotalcite group mineral material with double layer structure. Recently, to prevent the environmental pollution caused by greenhouse gases, especially CO₂, studies for production of synthetic meixnerite have been carried out. Meixnerite releases water vapour to the environment and reduces the CO₂ emission by replacing airborne CO₂ with OH groups present in its double layered structure through the adhesion of CO₂ on itself. The present study covers the synthesis and characterisation of meixnerite by sol-gel method. Aluminium-isopropoxide and magnesium-chloride-hexahydrate were used as initial materials. First, boehmitic sol was prepared using sol-gel method. The mixture was stirred vigorously after adding magnesium-chloride-hexahydrate into the boehmitic sol. The mixture obtained after the gelation process was heat-treated at 550, 1300, 1400 and 1500°C. The material which has [Mg₅Al₃(OH)₁₆][(OH)₃.4(H₂O)] chemical structure was determined as meixnerite which is a member of LDH group and used as CO₂ reducer.