Rapid in situ synthesis of MgAl-LDH on η-Al2O3 for efficient hydrolysis of urea in wastewater

Abstract A rapid and efficient synthesis strategy of MgAl-LDH was proposed. MgAl-LDH with high specific surface area was synthesized in situ by using η-Al2O3 as carrier, and the synthesis time was greatly shortened by both increasing temperature and introducing ethanol as co-solvent. Besides, the growth process of MgAl-LDH on the surface of η-Al2O3 is also revealed. Under optimized conditions, the specific surface area of the MgAl-LDH is as high as 172.4 m2/g, the crystalline size is as small as 12.82 nm, and the basicity can reach 1.795 mmol/g. The urea wastewater was degraded from 8000 mg/L to 6.85 mg/L over the catalyst synthesized by the rapid method, and the catalyst still maintains high activity after four uses. Also, it was found that there is a good linear relationship between the urea removal rate and the basicity of MgAl-LDH.