Novel nafion-palygorskite composite for Pb/Lead treatment

Clay minerals present promising characteristics for adsorbing heavy metals in aqueous solutions due to their low cost, non-toxic nature, and abundance. However, they often face limitations such as low adsorption capacity and poor selectivity. To address these issues, this study focused on improving the lead (Pb) adsorption capacity of palygorskite clay by modifying it with Nafion. Characterization techniques like Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) were employed to analyze the surface properties of both pristine and modified palygorskite clay, affirming the stability of the Nafion-palygorskite composite. Utilizing response surface methodology (RSM), the study examined the impact of various process parameters, including adsorbent dosage, Nafion amount, pH, and initial Pb concentration. Analysis of variance (ANOVA) revealed that these factors significantly influenced Pb removal efficiency, with pH and adsorbent dose being particularly impactful. The study found that a smooth Nafion-coated palygorskite clay surface, featuring sulfonate groups, led to improved Pb removal. Experimental results demonstrated that Pb removal efficiency increased from 3.6% to 69% using Nafion-palygorskite clay under specific conditions of pH and adsorbent dosage. Kinetic studies showed that both unmodified and modified palygorskite clay followed pseudo-first-order kinetics. Furthermore, the study explored machine learning (ML) algorithms for predicting aqueous Pb removal using Nafion-palygorskite adsorbent. Among these algorithms, the support vector machine (SVM) yielded the most accurate results, closely matching experimental findings. Overall, the research indicates that Nafion can effectively enhance the performance of clay-based adsorbents for treating heavy metal-contaminated water, offering potential for practical application in environmental remediation efforts.