Highly enhanced removal of Pb(II) and Ni(II) ions from water using FeMIL@CH composite beads: Adsorption and mathematical model driven studies

Adsorption is widely recognized as one of the simplest, most versatile, and cost-effective technologies for the removal of heavy metals from water. In this study , the metal organic framework such as MIL-101(Fe) was synthesized via a solvothermal method, followed by the preparation of FeMIL@CH composite adsorbent beads using a sol–gel process under acidic conditions . The characterization of adsorbent was done using SEM–EDX, TGA, XRD, FTIR and XPS analysis. The adsorption operating parameters such as adsorbent dose, pH, concentration and time of the adsorbent were optimized through batch experiment. The experimental data closely follows the Langmuir isotherm with high determination coefficient (R 2 > 0.98). The prepared FeMIL@CH adsorbent beads exhibited excellent Pb(II) and Ni(II) Langmuir adsorption capacity of 92.59 and 116.95 mg/g which were close to the experimental adsorption capacity of 85.55 and 107.25 mg/g respectively. The higher R 2 value of the pseudo-second-order (PSO) kinetic model compared to the pseudo-first-order (PFO) model indicates that the adsorption process is primarily governed by chemisorption rate-limiting step. The high correlation coefficient values ( R > 0.98) indicate that the artificial neural network (ANN) model accurately predicted the experimental data. Overall, the developed FeMIL@CH beads show strong potential as an alternative adsorbent for the remediation of heavy metal-contaminated water and the mitigation of environmental water pollution.