3.3.5. Mineralization
In order to investigate the mineralization of AR73, the TOC
analysis was carried out during the photocatalysis of AR73 for the
initial dye concentration of 200 mg/L. Experimental conditions
were set based on the obtained optimum parameters, including the
initial pH of 5, MgO nanoparticles dosage of 0.8 g/L and contact
time of 60 min. Although, the complete decolorization of AR73was
observed within 60 min, the TOC removal reached to 98% after
300 min (Fig. 5). The longer required time for TOC removal
compared to decolorization was due to decomposition of AR73
molecule into intermediate metabolites such as aldehydes and
aliphatic acids (Pang and Abdullah, 2013).
3.4. Sequencing coagulation-photocatalytic degradation