Dead biomass of Morganella morganii acts as an efficient adsorbent to remove Pb(II) from aqueous solution in different aeration-agitation and pH conditions

Lead (Pb) removal from industrial effluent using physicochemical methods, though efficient, poses economic and environmental challenges due to high cost and generation of toxic wastes as by-products. Biosorption using dead microbial biomass, on the other hand, offers economic feasibility and environmental safety, but its application is limited because it relies on specific pH and agitation conditions. To address these issues, we used wastewater of a drain containing effluent from nineteen industries and isolated Pb-tolerant strains of Morganella morganii (ND1 and ND2). We demonstrated that the dead biomass of M. morganii ND1 and ND2 maintains a high biosorption potential at pH ranging from 3 to 5 in both shaking (89.96-89.99 mg/g) and static conditions (89.99-84.05 mg/g). Adsorption of Pb(II) from M. morganii ND1 and ND2 follows pseudo-second-order kinetic model and chemisorption as a dominant underlying mechanism in aqueous media. Fourier-transform infrared spectroscopic analyses of dead biomass before and after Pb(II) biosorption revealed the involvement of phosphoryl, hydroxyl, amide, carbonyl, and phosphate functional groups during biosorption. We demonstrated the potential of M. morganii ND1 and ND2 in developing a cost-effective biosorption technology for removing Pb in industrially relevant pH, and both agitation and static conditions.