Agitation was provided for 1 h contact time which is sufficient to reach equilibrium with a constant agitation speed of 600 rpm and 18±2°C. The pH was adjusted by adding a few drops of diluted NaOH or HNO3.
Agitation was provided for 1 h contact time which is sufficient to reach equilibrium with a constant agitation speed of 600 rpm and 18±2°C. The pH was adjusted by adding a few drops of diluted NaOH or HNO3.