Facile synthesis of ZnAl-layered double hydroxide microspheres with core–shell structure and their enhanced adsorption capability

• ZnAl-LDH microspheres with core–shell structure have been synthesized by a simple solution route.
• The stepwise growth mechanism is responsible for the formation of ZnAl-LDH microspheres.
• The microspheres combine high surface area with accessible diffusion pathways of porous networks.
• The microspheres show excellent adsorption capacity towards methyl orange in aqueous solutions, endowing LDH microspheres with promising applications for wastewater purification.

We have developed a simple solution route for the synthesis of hierarchical ZnAl-layered double hydroxide (ZnAl-LDH) microspheres with core–shell structure, which have great practical application as the efficient adsorbent for wastewater purification. The evolution of the morphology with time suggests that the hierarchical ZnAl-LDH microspheres formed by a stepwise growth mechanism. The results demonstrate that the as-prepared ZnAl-LDH microspheres exhibit more excellent adsorption capacity (523 mg/g) towards methyl orange in aqueous solutions as compared with the LDH microspheres previously reported, result of which is attributed to their enhanced surface area and suitable mesopore distribution. This work provides a promising approach for the synthesis of hierarchical porous materials with excellent adsorption capacity, which can be potentially used in wastewater treatment.