Biosorption of Cd+2 and Pb+2 by Exopolysaccharide Extracted From Lactobacillus Fermentum 6B; Adsorption Isotherm and Kinetic Studies



Kermanshahi RK¹ ; Khaniki GJ² ; Goudarzi L¹ Show Affiliations
Source: Iranian Journal of Public Health Published:2023

Abstract

Background: In recent years, the biosorption of heavy metals by Lactobacillus strains has received attention from researchers. We aimed to remove of heavy metals lead and cadmium from L. fermentum 6b exopolysaccha-ride in 2021. Methods: Extracellular exopolysaccharide was first extracted from selected probiotic strain, and then the effect of variables such as pH, the extracted exopolysaccharide adsorbent dose, contact time, heavy metal concentra-tion, and temperature on the adsorption rate was investigated. The adsorption isotherms of Langmuir and Freundlich were also examined. Pseudo-first and pseudo-second-order kinetics equations were also investigated for the desired surface adsorption. Results: The adsorption process at pH=6.5, contact time=80 min, pollutant concentration=100 mg.L-1, adsor-bent dose (extracted exopolysaccharide) =1500 mg.L-1, temperature=35°C for cadmium; pH= 6, contact time=60 min, contaminant concentration of 100 mg.L-1, adsorbent dose (extracted exopolysaccharide) =1500 mg.L-1 temperature=of 35 °C for lead had optimum condition. The adsorption process corresponded to Freundlich isotherm with R2=0.958 and R2=0.988, and pseudo-second-order kinetic with R2=0.99 and R2=0.85 for cadmium and lead, respectively. Conclusion: The exopolysaccharide extracted from L. fermentum 6b isolate can have an acceptable removal potential for lead and cadmium heavy metals. © 2023 Kermanshahi et al.