Synthesis of layered double oxide with high specific surface area by innovative sol-gel method through its application to arsenate anion adsorption

Abstract

Layered double oxides (LDO) are effective in removing toxic anions from aqueous solutions; however, related synthesis studies have not been thoroughly presented. In this study, we successfully established a new method for the sol-gel synthesis of LDO. This new synthesis method, in which organic chains are added in the sol-gel synthesis process, is simple and fast and improves the adsorption capacity. The specific surface area of the LDO synthesized by the sol-gel method was approximately 2.6 times larger than that of the LDO synthesized by the coprecipitation method. In addition, LDO synthesized by adding organic chains in the sol-gel synthesis process showed further improvement in specific surface area. A specific surface area value approximately 2.7 times higher than that of LDO synthesized by the coprecipitation method was obtained. The maximum adsorption amount calculated from the Langmuir equation for the arsenic adsorption on the LDO synthesized by the sol-gel method was 282.6 mg/g. It was confirmed that the adsorption capacity of LDO increased with an increase in the specific surface area, and LDO with an increased adsorption capacity were successfully synthesized using this method.