Lead removal from natural zeolite through optimized HCl leaching using response surface methodology

Abstract

ABSTRACT This study encompasses the extraction of Pb through leaching from zeolite ore sourced from Gördes, Turkey. A three-level, three-factor full factorial experimental design with 6 replicates was employed in the leaching tests. The results were analyzed using response surface methodology, and the impact of process variables on the procedure is depicted in the form of 3-D response graphs. According to the findings of the study, the optimal leaching conditions were achieved at a temperature of 80°C, a solid ratio of 15% solids, and a pH of 0.5. Under these optimal experimental conditions, the Pb content of the zeolite decreased from 56 ppm to 8.12 ppm. The lead content of the resulting product is significantly lower than the maximum lead concentration allowed for zeolite ores used in animal feed additives. To assess the potential release of heavy metals from zeolite samples, the EPA-TCLP 1311 test was conducted. The results indicate that a certain level of heavy metals is released from the raw zeolite samples, whereas no such release is observed from the leached zeolite.