A Novel Calcium Oxalate/Sepiolite Composite for Highly Selective Adsorption of Pb(II) from Aqueous Solutions

Synthesizing functional nanomaterials from naturally abundant clay has always been of vital importance for resource utilization, however, the lack new methods to effectively utilize low-grade presents a significant challenge. Herein, calcium oxalate/sepiolite nanocomposite (SMN-x) was prepared by using water bath heating method convert associated carbonate in sepiolite into oxalate. The developed composite subsequently used remove Pb(II) aqueous solutions. SMN-3 adsorbent at 90 °C 3 h (with high specific surface area 234.14 m2·g−1) revealed maximum adsorption capacity 504.07 mg·g−1 pH 5, which about five times higher than that (105.57 mg·g−1). Further, possessed much selectivity as compared other metal ions. Moreover, residue noted be stable and safe. kinetics isotherms conformed quasi-second-order kinetic Langmuir models. During process, ion exchange main mechanism, it also accompanied electrostatic attraction. This study provides novel strategy sustainable development simple efficient adsorbents utilizing minerals.