Millimetre-sized hollow LDH-based composite microspheres: A novel adsorbent for selective adsorption and continuous...

Tungsten (W) and molybdenum (Mo) are important rare refractory metals that are widely used in high technology fields. With the rapid development of strategic emerging industries and high-end manufacturing, the efficient separation of W and Mo has become a problem that must be solved in industrial production. However, the two in aqueous solution show similar ionic radius, oxidation state and coordination chemical properties, so that W-Mo separation has long been a technical bottleneck in industrial production. In order to address the problems of complicated process, limited separation coefficient and difficult industrialisation of the traditional separation methods, this study innovatively designed and synthesized millimetre-sized hollow CoAl-LDH/sodium alginate composite microspheres (HCASA). This HCASA combines the high selectivity of CoAl-LDH with the moldability of sodium alginate. Moreover, the hollow structure significantly enhances the active adsorption interface and mass transfer efficiency. The adsorption capacity of HCASA for W was up to 106.0 mg/g within 3 h, and the W-Mo separation factor was as high as 19.3, which was significantly better than that of the corresponding solid microspheres (CASA), and maintains an excellent W-Mo separation performance in column separation experiments. This study provides an innovative material and strategy for the efficient, continuous and recyclable separation of W and Mo, and provides a new technological approach for the green recycling and efficient use of metal resources.