Scalable preparation of monodisperse micron-sized carbon microspheres and their application in anion-exchange chromatography

Abstract

Polyacrylic acid sodium (PAAS), which is an anionic water-soluble polymer, is widely utilized as a thickener in the food industry and flocculant in water treatment owing to its high anion density, low cost and nontoxicity. Herein, we report for the first time the synthesis of monodisperse micron-grade carbon microspheres (CMSs) through the hydrothermal carbonization of sucrose with the assistance of trace PAAS, and their potential application as a green stationary phase for ion chromatography. An appropriate amount of PAAS efficiently inhibits the crosslinking of the formed CMSs, which results in monodispersity. The hydrothermal method was proven effective at a high sucrose concentration and for scalable experiments. The average size of the CMSs could be facilely regulated from 1.2 μm to 5.0 μm via hydrothermal time, temperature and sucrose concentration. The hydrothermal CMSs were further modified with quaternary ammonium groups based on the polycondensation of methylamine and 1,4-butanediol diglycidyl ether. Utilizing the quaternized CMSs as an ion chromatography stationary phase and potassium hydroxide solutions as the mobile phase, common inorganic anions were well separated with good symmetrical peak shapes and high stability.