Effect of structural evolution of attapulgite on Pickering foam and fabrication of porous materials for removal methylene blue

In recent years, attapulgite (APT) has attracted wide attention in the stabilizing Pickering foam due to the excellent colloidal properties, nanorod morphology, porous structure, and good biocompatibility, etc. However, the defects of the crystal structure are often neglected in the study of stabilizing two-phase incompatible interfaces. Herein, the properties of Pickering foam stabilized by APT with structural evolution using the oxalic acid and Sapindus mukorossi were systematically investigated. With the increase of acid etching time, the contact angle of the modified APT gradually increased and the APT was transferred from the continuous phase to the air-water interface of Pickering foam. Pickering foam was used as templates to fabricate porous materials, and the adsorption experiments showed that the porous materials prepared from APT with intact crystal structures had excellent removal rate at low concentration dye, and the removal rates exceeded 98% at dye concentration of 10 mg/L. While the porous materials prepared from APT with large crystal defects had advantages in adsorption at high concentration dye with a maximum adsorption capacity of 952.62 mg/g. More importantly, the waste adsorbents were used to prepare soil conditioner, and the pH, cation exchange capacity, electrical conductivity of the soil were increased from 4.58, 18.10 cmol/kg and 0.52 mS/cm to 6.44, 23.68 cmol/kg and 1.06 mS/cm respectively. This study provided new insights and ideas for the green preparation and sustainable application of porous materials.

Automated summary

In recent years, attapulgite (APT) has gained wide attention in stabilizing Pickering foam due to its excellent properties. This study investigated the properties of Pickering foam stabilized by APT with structural evolution using oxalic acid and Sapindus mukorossi. The results showed that APT with intact crystal structures had excellent removal rate at low concentration dye, while APT with large crystal defects had advantages in adsorption at high concentration dye. Furthermore, the waste adsorbents were used to prepare soil conditioner, improving the pH, cation exchange capacity, and electrical conductivity of the soil.