Environmental Engineering Reference
Fig. 2 UV-vis spectrophotometric data to demonstrate the surface fi ctionalization of iron nanopar-
ticle by SDS and GSH with control
To investigate the effect of surface modifi cation on absorption spectra, the surface
modifi ed nanoparticles were subjected into UV-vis spectrum and observed spectro-
photometrically. Figure 2 shows the UV-vis absorption spectrum of bare nanopar-
ticle, free SDS and SDS coated nanoparticle, Glutathione and Glutathione coated
nanoparticle. The free glutathione exhibited a characteristic absorption peak at
280 nm (curve red). No absorption peak was observed for free SDS (curve black).
However, the SDS (curve purple) and Glutathione (curve green) modifi ed nanopar-
ticle showed different absorption spectra compared with the bare nanoparticle
(curve blue) and considered as successfully modifi ed.
The growth curve data of E. coli DH5ʱ and B. subtilis under normal condition
clearly depicted the separate growth phases as shown in Fig. 3a, b ) but under the
infl uence of various concentration of iron nanoparticle (100 and 200
log phase was shown to be affected for both species with increasing concentration
of nanoparticle in negligible quantity, indicating the least toxic nature of the
nanoparticle at the studied concentration.
Glutathione fi ctionalized nanoparticle was taken into Erlenmeyer fl ask under
continuous shaking condition containing various concentration of potassium di-
chromate and the amount of Cr(VI) remained in the liquid phase after magnetic
separation was determined spectrophotometrically against standard. The concentra-
tion of the nanoparticle has signifi cant effect on the removal of Cr(VI) (Fig. 4i ) and
its role has been studied at various pH (3 and 11) (Fig. 4iia, b ). Among the various
concentrations of nanoparticle as adsorbent (100, 200 and 400
nanoparticle concentration was found to be maximum with respect to the Cr(VI)
adsorption effi ciency and this concentration was selected for further studies.