Synthesis of Three-Dimensional Hierarchical Flower-Like Mg–Al Layered Double Hydroxides with Excellent Adsorption Performance for Organic Anionic Dyes

In this work,a facile and effective strategy to prepare three-dimensional (3D) hierarchical flower-like Mg–Al layered double hydroxides (3D-LDH) was developed via a one-step double-drop coprecipitation method usingγ-AlOparticles as a template.The characterization and experimental results showed that the calcined product,3D-LDO,features a large specific surface area of 204.2 m ~2/g,abundant active sites,and excellent adsorption performance for Congo red (CR),methyl orange(MO),and methyl blue (MB).The maximum adsorption capacities of 3D-LDO for CR,MO,and MB were 1428.6,476.2,and 1666.7 mg/g,respectively;such performance is superior to that of most reported adsorbents.The adsorption mechanism of organic anionic dyes by 3D-LDO was extensively investigated and attributed to surface adsorption,the memory effect of3D-LDO,and the unique 3D hierarchical flower-like structure of the adsorbent.Recycling performance tests revealed that3D-LDO has satisfactory reusability for the three organic anionic dyes.