Physical characterization and kinetic studies of Zn (II) biosorption by Morganella morganii ACZ05

Abstract

Through this investigation, we establish the mechanism and physical characterization of zinc (II) sequestration by Morganella morganii ACZ05 strain, which was isolated and characterized from soil polluted by effluents from electroplating industries. As far as we know, there is very little literature concerning zinc biosorption using an environmental strain of Morganella morganii. The SEM analysis shows the dark porous gaps in the aggregated cell-matrix of test bacterial biomass which is inferred as water channels usually seen in biofilms, as compared to metal-unexposed control. Morganella morganii is not known to produce biofilms unless in the rare nosocomial conditions. Here, SEM analysis shows the production of biofilms after exposure to zinc (II) at 500 ppm, which has not been previously reported. EDX analysis of bacterial biomass also specified the sorption of zinc (II) by the bacterial cells and the presence of new peaks for zinc in contrast to control. Both XRD and FTIR analysis observations strongly implicate the potential of physical adsorption as a mechanism for heavy metal resistance. Analysis of the cell surface by Atomic force microscopy and examination of the topography revealed cell aggregation occurs during biofilm production after zinc biosorption. Unlike other reports, regular models such as Langmuir isotherm and Freundlich isotherm were found insufficient to explain the physisorption of zinc (II) metal ions on the complex multicomponent adsorbents such as the exopolymeric surface of the bacterial cells. However, adsorption kinetics of zinc (II) to the bacterial biomass was most effectively elucidated by a pseudo-second-order kinetic model, suggesting a certain kind of chemisorption that requires further study.

Exploring Modified Rice Straw Biochar as a Sustainable Solution for Simultaneous Cr(VI) and Pb(II) Removal from Wastewater: Characterization, Mechanism Insights, and Application Feasibility

“…The variations between functional groups and their concentrations with band association are similar to the variations in band intensity. 23 Compared to the untreated rice straw biosorbent, the treated adsorbent's spectra were shifted to a small range, which was observed in Figure 2a2. The shifts observed in the biomass were due to the binding action of Cr and Pb metal ions with amino and hydroxyl groups.…”

“…The peak at 1050 cm –1 indicates the broad band in medium intensity level, and it was assigned to υ (C–O–C) asymmetrical stretching. The variations between functional groups and their concentrations with band association are similar to the variations in band intensity …”

“…The variations between functional groups and their concentrations with band association are similar to the variations in band intensity. 23 …”