Design and Characterization of Concave Hollow Double-Layer Nanospheres for Efficient Cd(II) and Pb(II) Adsorption

• Published in: Langmuir Vol. 41; no. 16; pp. 10323 - 10331
• Main Authors: Jing, Fangfen, Xu, Xin, Lu, Weiwei, Jin, Mingzhu, He, Xinyang, Yu, Rongtai
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 29.04.2025
• Subjects: adsorbents; adsorption; Fourier transform infrared spectroscopy; heavy metals; ion exchange; ligands; nanospheres; porosity; Raman spectroscopy; remediation; sorption isotherms; thermogravimetry; transmission electron microscopy
• ISSN: 0743-7463; 1520-5827; 1520-5827
• DOI: 10.1021/acs.langmuir.5c00146

Polymer-based adsorbents have emerged as promising candidates for heavy-metal remediation due to their tailorable porosity and multifunctional surfaces, yet challenges persist in achieving both structural precision and adsorption efficiency. Here, we report a concave hollow double-layer nanosphere (CHDN) synthesized through a facile self-assembly strategy engineered for selective capture of Cd­(II) and Pb­(II) ions. Comprehensive characterization via transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and thermogravimetric analysis (TGA) confirmed the hierarchical architecture with abundant amino/hydroxyl moieties. The CHDN demonstrated exceptional adsorption capacities of 198.40 mg/g for Cd­(II) and 60.34 mg/g for Pb­(II), outperforming conventional adsorbents. Isotherm analysis revealed Cd­(II) adsorption followed the Sips model (R 2 > 0.99), while Pb­(II) adhered to the Langmuir model, suggesting monolayer and heterogeneous binding mechanisms, respectively. Kinetic studies further corroborated chemisorption dominance through pseudo-second-order fitting for Cd­(II) and Elovich compatibility for Pb­(II). We propose a synergistic mechanism involving ligand complexation and ion exchange, facilitated by the dual functionality of surface groups and structural advantages of the concave architecture. This work provides a blueprint for designing spatially engineered polymers for environmental remediation.