Spatiotemporally ordered topological transformation in layered double hydroxides enables synergistic mineralization of As<sup>III</sup>/Cd<sup>2</sup>.

Zheng, Meiqi; Du, Huanxu; Cao, Xiaoqing; Xu, Si-Min; Chen, Wei; Shi, Wenying; Kong, Xianggui; Shao, Mingfei et al. · Nat Commun · 2026

basic_science · Level V

Where this comes from

Abstract

The co-contamination of arsenite (As<sup>III</sup>) and cadmium (Cd<sup>2+</sup>) poses a significant challenge in environmental remediation due to their divergent chemical speciation and transformation pathways. Here, a redox-active layered double oxide (MgMn-LDO) is designed, and achieves adsorption capacities of 821.7 mg g<sup>‒1</sup> for As<sup>III</sup> and 1895.6 mg g<sup>‒1</sup> for Cd<sup>2+</sup> in their coexisting system, presenting a state-of-the-art performance. Unexpectedly, the co-adsorption system not only enhances individual adsorption capacities but also accelerates the adsorption rate by 181‒fold compared to single-component systems. The LDO undergoes a four-stage spatiotemporally ordered topological transformation, which effectively decouples the oxidation of As<sup>III</sup> from the adsorption of Cd<sup>2+</sup> and reverses the conventional competitive sequence. This stepwise mechanism ensures preferential oxidation of As<sup>III</sup> to As<sup>V</sup>, followed by the alteration of Cd<sup>2+</sup> adsorption pathway to isomorphous substitution, expanding diffusion pathways and accelerating As immobilization. Large-scale experiments demonstrate this material's potential in synergistic remediation As/Cd in mining wastewater and contaminated soils.