The treated effluents with different concentrations of adsorbent
dosage are characterized with AAS for the trace amounts of heavy
metal ions in the solution. Fig. 8 shows the AAS spectrum analysis.
This shows that when the concentration of GO is increased, the
large heavy metal ions are removed/adsorbed by GO. The presence
of high concentrated Ni in pharma-effluent gradually decreased
when the GO concentration is increased. Cr and Pb are appeared as
trace amounts which were completely removed by grapheneoxide
nanosheets. This is due to the fact that the GO contains a
larger number of functional groups which increase adsorption sites
causing the large metal ion adsorption [33]. The detailed
mechanism of adsorption and their kinetic models are given in
the Mechanism of adsorption of heavy metal ions by GO section