Synergistic Effect of Porous Layered Lanthanum Hydroxide for Efficient Br− Adsorption

Abstract

Porous layered hydroxides has garnered significant attention for ion adsorption applications due to their unique combination of layered and porous structures. Herein, porous layered lanthanum hydroxide nanowires (NWs) is synthesized to efficiently adsorb Br⁻, utilizing the modulation of interlayer ions to optimize their performance. These NWs exhibit a porous surface structure and a positively charged surface, which increases the number of active sites and enhances their affinity for Br⁻. The layered hydroxide lanthanum acetate (LHL-acetate) NWs possess an adsorption capacity of 221 mg g⁻¹, a wide range of pH suitability (from 3.0 to 10.0) and remarkable stability, surpassing many previously reported adsorbents. The superior Br⁻ adsorption performance of LHL-acetate NWs can be attributed to the synergistic effect between ion-exchange properties of interlayer anions and surface adsorption facilitated by the porous structure, which strengthens electrostatic interactions at the adsorbent-solution interface. Impressively, these NWs achieved 100% Br⁻ removal from simulated wastewater with varying initial concentrations and flow rates in a fixed-bed adsorption system, highlighting the effectiveness of LHL-acetate NWs for advanced Br⁻ removal in practical applications. This study reveals the structure-reactivity relationship of porous layered lanthanum hydroxide adsorbents and offers insights for the application of such materials in the adsorption domain.