Zeolite with Remarkable Pb and Cd Removal Capability Cost-Effectively Synthesized from Postprocessed Natural Stellerite.

zeolite, a low-silica zeolite with an 8-membered ring aluminosilicate framework, has been recognized as a promising material in sorption, separation, and ion-exchange applications. Herein, we developed a cost-effective and rapid method to convert parent zeolite H-, which was derived from natural stellerite, into zeolite through interzeolite conversion with a crystallization time of 8 h. This zeolite exhibits high efficiency in removing Pb and Cd from simulated heavy metal wastewater over a pH range of 3-8. It also shows excellent selectivity in the presence of competitive cations, including Na, K, Ca, Mg, Zn, Cu, and Co. At 25 °C, with a -S dosage of 1/3000 g·mL for Pb and 1/500 g·mL for Cd, the removal efficiencies were 99.7 and 99.9%, respectively. The distribution coefficients were 1097 L·g for Pb and 550 L·g for Cd, and the sorption capacities reached 513 mg·g for Pb and 171 mg·g for Cd, indicating that the product zeolite is one of the highest sorbents for Pb and Cd reported for zeolitic materials. The sorption for Pb and Cd both follows the chemisorption-dominated mechanism, driven by the ion-exchange process between the K in the channels -S and the Pb or Cd in solution. This work highlights the potential of rapidly synthesized zeolite for the effective removal of heavy metal cations, emphasizing its performance and practical applicability.