A novel method for the preparation of spherical cellulose-tungsten carbide composite matrix with NMMO as nonderivatizing solvent

摘要

N-methylmorpholine-N-oxide (NMMO) was used as the nonderivatizing solvent for dissolving cellulose, and the cellulose-tungsten carbide composite particles were prepared with water-in-oil suspension and cooling regeneration. Some key factors, such as dissolution temperature and time, water content, cellulose concentration, dispersion, and cooling were optimized. The solubility of cellulose in the NMMO solution was greatly dependent on the water content, which should be controlled at the range of 11 to 15 wt %. In addition, the influences of water content of the cellulose/NMMO/water solution on the properties of composite beads were studied, including bead size, wet density, and pore properties. It was found that 13 wt % water content was most appropriate. The expansion and liquid mixing properties of composite beads in an expanded bed were also explored. The results indicated that the cellulose composite beads prepared could be used as the matrix for expanded bed adsorption processes. Compared with the traditional technology with cellulose xanthate viscose, new method based on the NMMO dissolution is more environment-friendly, reduces the process time and shows a potential application for large scale preparation.