Impact of bacterial cell concentration on microbial-mediated cerium carbonate precipitation for efficient heavy metal removal: Insights from adsorption isotherm, kinetics, and thermodynamics

Abstract

Heavy metals (HMs) pollution is a pervasive environmental issue needs significant attention through bioremediation. Present study investigated the potentiality of Microbial-mediated Cerium Carbonate Precipitation (MMCCP) in simultaneous removal of HMs (Cr, Pb, and Cu) using different cellular concentration of Sporosarcina pasteurii. Results from SEM analysis revealed formation of spherical and rod-like structures (∼112nm), and finally XRD and FTIR confirmed the formation of high-purity crystalline ${\mathrm{CeCO}}_3\mathrm{OH}$ with surface-bound hydroxyl groups and ${\mathrm{CO}}_3^{2-}$ ions, indicating successful cerium incorporation and formation in ${\mathrm{CeCO}}_3\mathrm{OH}$. Moreover, optimal removal efficiencies for Cr (99%), Pb (99%), and Cu (68%) were achieved within 80min at 6mg/L concentration and 0.05g adsorbent dose. Adsorption followed the Langmuir isotherm (R² = 0.9) and pseudo-second-order kinetics, with thermodynamic parameters indicating spontaneity and exothermicity (ΔG < 0, ΔH < 0, ΔS > 0). These findings demonstrate MMCCP’s potential as an effective and sustainable approach for HMs remediation.