Industrial Preparation Of Layered Double Hydroxides With High Specific Surface Area And Their Adsorption Properties Studies

Layered Double Hydroxides (LDHs) is a kind of two-dimensional inorganic materials, which has been used or has potential application in flame-retardant, PVC stabilizer, IR-absorbing, UV-blocking, catalyst, electrochemical energy-storage and so on. However, the low specific surface area of normal LDHs (N-LDHs) severely hinders the application of LDHs and LDH-based materials, especially in the areas that material properties are influenced by its specific surface area, including catalyst and electrochemical energy-storage fields.In this paper, various kinds of LDHs with high specific surface area (SSA) were prepared using acetone treatment (AT) method. By optimizing the preparation conditions, the highest SSA for AT-Mg2Al-CO3-LDHs, AT-Ni2Al-CO3-LDHs, AT-Zn2Al-CO3-LDHs and AT-Mg3Al-CO3-LDHs samples are as high as 123.5,254.7,54.5 and 195.0 m2/g, respectively. Taking into consideration the low toxicity, low cost and environmental friendliness of AT-Mg3Al-CO3-LDHs, we studied the adsorption performance of its calcined product (AT-Mg3Al-LDO) toward heavy metal Cr(VI) in K2Cr2O7 solutions. The adsorption capacity of AT-Mg3Al-LDO measured by ICP-AES technology was calculated to be 55.91 mg/g, which is 2.4 times higher than that of normal LDO (denoted as N-LDO, calcined product of N-LDHs). The absorption equilibrium of AT-LDO was achieved after 180 min, with six times faster than that of N-LDHs. This result indicates the adsorption performance is largely enhanced by using AT-Mg3Al-LDO as adsorbent.We further studied the engineering technology of acetone treatment for scaling up of AT-Mg3Al-CO3-LDHs. By utilizing pilot-scale equipments (including pilot reaction device, ceramic membrane, etc), the industrial preparation of AT-Mg3Al-CO3-LDHs was achieved. We obtained 2.7 Kg LDHs with specific surface area of 174.5 m2/g. Therefore, this research provides a facile and cost-effective method to prepare highly dispersed AT-LDHs, which offers original data and exploration for industrial production of LDHs with high specific surface area.