Multiple transfer pathways and dense high-energy sites enable high-capacity, ultra-fast, and efficient Pb(II) capture by porous silicate architecture
Adsorption techniques are crucial for removing high and trace levels of heavy metal pollutants from water, enabling effective pollution control without causing secondary contamination. Achieving “all-rounder” adsorbents with high capacity, efficiency, speed, and cost-effectiveness is challenging. Materials with structural defects, firm surface charges, and porous structures are ideal for rapid and efficient mass transfer. Herein, using a “homologous transformation” strategy, we converted abundant kaolin into 4A and Na-P1 zeolites-based porous silicate adsorbents with enhanced surface active sites and optimized adsorption pathways. Site energy analysis confirmed that these upgraded structures have high-density, high-energy adsorption sites, facilitating rapid Pb(II) removal from water. These zeolite-based adsorbents exhibit exceptional Pb(II) adsorption capacities (416.60 mg/g for 4A and 400.21 mg/g for Na-P1) and ultra-fast initial rate constants (409.84 and 617.28, which are 174.62 and 263.01 times greater than those of kaolinite; and 56.56 and 85.19 times greater than those of commercial activated carbon, respectively). DFT calculations verified strong adsorption forces for Pb(II) (adsorption energy: −0.52 eV). Removal efficiencies reached 99.75 % for 4A and 99.96 % for Na-P1 zeolite-based adsorbents, ensuring treated water is safe and supports seed germination and plant root growth. These adsorbents also perform well in the presence of interfering ions like Zn(II), Cu(II), Cd(II), and Ni(II). After 10 regeneration cycles, they retain over 73 % of their original capacity, demonstrating an optimal balance among capacity, speed, efficiency, and interference resistance, aligning with sustainable development principles of “from nature, for nature”.
危险品化学品经营许可证（带存储）