3.2. Relationship between heavy metal removal and wastewater pH
In order to study, the relationship between pH and removal of
heavy metals through precipitation and absorption, heavy metal
concentration and pH were examined during the experiment. Initially, pH of RG wastewater was slightly alkaline (Table 1) and
during the experiment, pH varied from neutral to slightly alkaline
(6.8270.03–7.9270.02). This might be due to the fact that there
is addition of oxygen through dissolution of atmospheric oxygen
and photosynthetic activity by the plant. In the present study, the
pH varied from neutral to slightly alkaline, which revealed that the
possible mechanism of metal removal was mainly due to metal
immobilization in rhizosphere and absorption through their roots
and partially by precipitation. Similarfindings were reported by
Barakat (2011), who described the removal of metals through
chemical precipitation under alkaline condition (pH 9–11)