环境材料与生态化学研究发展中心知识库

Though great progress on the adsorbents of heavy metal ions has been made in recent years, it is still challenging to develop economic, high-efficient and eco-friendly adsorbents. Herein, a series of MgO/palygorskite (MgO/Pal) composites with robust adsorption performance toward Zn(II) and Cd(II) were successfully prepared by a facile and industrially feasible precipitation-calcinations process using environmentally benign natural palygorskite (Pal) and Mg(II)-rich brine as the raw materials. The XRD, TG and SEM analyses confirm that MgO species was formed and uniformly distributed on the surface of Pal nanorods. The resultant MgO/Pal adsorbent exhibited high adsorption capacities of 841 and 669 mg/g for Zn(II) and Cd(II) ions, respectively. About 98.79% of Zn(II) and 98.69% of Cd(II) were removed from 200 mg/L of the initial solution by only using 1 g/L of the adsorbent. The spent MgO/Pal adsorbent can be regenerated by a simple one-step calcinations process, and the regenerated adsorbent can remove 99.5% of cationic dyes from 100 mg/L of the initial dye solution. The adsorption process obeys Langmuir isotherm model and pseudo-second-order kinetic model, which suggest the monolayer adsorption of Zn(II) and Cd(II) onto the composite. The chemo-adsorption process including phase transformation and precipitation is mainly responsible for the enhanced adsorption capacities. In a word, the composites are made from naturally available matters, which can serve as promising adsorbents for high-efficient removal of toxic metal ions from polluted water.