The ever-growing contamination of water resources generated by heavy metals is posing significant threat to sustainable development, and urging the necessity of safe disposal. In this work, we designed a facile method to prepare carbon dots/Mg(OH)₂ (marked as CDs/Mg(OH)₂) composite, which enables to remove and recover potentially toxic metal of Cd²⁺ from water. The newly-prepared CDs/Mg(OH)₂ features a hierarchical petaloid-array structure and has large specific surface area of 96.2 m² g⁻¹. It is evident that the composite is composed of Mg(OH)₂ slices, to which CDs are attached. Density functional theory calculation recognized the composite microstructure at the atomic level. Weak chemical coupling between sub-units were borne out by optimized structures, energetics, infrared vibrations, and electronic structures. The CDs/Mg(OH)₂ composite shows high removal capacity and long durability while treating Cd(II)-contaminated water. The incorporation of CDs could regulate and control the up-taking rate of Cd²⁺ ions and consequently fabricate well-dispersed 1D nanowires of Cd(OH)₂. The corresponding mechanism was proposed. Specifically, the sample CDs/Mg(OH)₂-60 reaches 1015.4 mg g⁻¹ removal capacity; it can be used for 12 cycles and still keep removal efficiency as high as 98.6%.

重金属产生的水资源污染日益严重，对可持续发展构成了重大威胁，并敦促安全处置的必要性。在这项工作中，我们设计了一种简便的方法来制备碳点/ Mg（OH）₂（标记为CDs / Mg（OH）₂）复合材料，该方法能够从水中去除和回收有毒的Cd ²⁺金属。新制备的CDs / Mg（OH）₂具有分级的花瓣状阵列结构，并且具有96.2m ² g ^-1的大比表面积。显然，复合材料是由Mg（OH）₂组成的附带CD的切片。密度泛函理论计算在原子水平上识别出复合微结构。优化的结构，高能学，红外振动和电子结构证明了子单元之间的弱化学偶联。CDs / Mg（OH）₂复合材料在处理受Cd（II）污染的水时显示出较高的去除能力和较长的耐久性。CD的掺入可以调节和控制Cd ²⁺离子的吸收速率，因此可以制造出分散良好的Cd（OH）₂纳米线。提出了相应的机制。具体而言，样品CDs / Mg（OH）₂ -60达到1015.4 mg g ^-1清除能力；它可以使用12个循环，并且仍保持高达98.6％的去除效率。