Adsorption Isotherm
In order to determine the sorption capacity of NR5 biosorbent it is required to generate an equilibrium data set which can further be subjected to Langmuir and Freundlich adsorption isotherm equation. Biosorption potential of NR5 was evaluated at concentration of 100 mgL-1 of As (V), and found that concentration of arsenic (V) on NR5 cell surface increased with time progression, and reached at a saturation point. This possibly because of high availability of arsenic in medium and thus result in enhanced arsenic biosorption capacity. Further when all surface is entirely covered with As (V) adsorption potential reached to limit, and can be defined as maximum biosorption capacity. The results suggested that both Langmuir and Freundlich isotherm fitted, although Langmuir was comparatively more demonstrative than Freundlich (Figure 2a) with a higher correlation coefficient value (R2). Freundlich exhibits some degree of linearity but Langmuir model was perfectly fit (Figure 2b). Thus, results advocated of monolayer adsorption possibly due to topology of bacterial (NR5) cell and binding sites. In addition to this when adsorption behavior was evaluated using Elovich, Pseudo-first order reaction couldn’t explain adsorption precisely due to its low correlation coefficient value, although on the other hand second-order kinetic model pronounced adsorption fittingly with correlation coefficient R2 > 0.992. Thus, pseudo second order kinetic model was best fitted in arsenic removal