Jn. Wu et al., OPTIMIZATION OF THE REACTION CONDITIONS FOR ENZYMATIC REMOVAL OF PHENOL FROM WASTE-WATER IN THE PRESENCE OF POLYETHYLENE-GLYCOL, Water research, 27(12), 1993, pp. 1701-1706
The effect of the additive, polyethylene glycol (PEG), on the horserad
ish peroxidase (HRP) catalysed removal of phenol from wastewater has b
een studied over the phenol concentration range of 1-10 mM (0.1-1.0 g/
l). The optimum pH, HRP concentration, PEG concentration and the molar
ratio of hydrogen peroxide and phenol have been investigated in the p
resence of PEG at room temperature in order to achieve the maximum phe
nol removal efficiency with the minimum cost. The effect of concentrat
ions of HRP and PEG on reaction time was also investigated. Experiment
al results showed that the addition of PEG had significant protective
effect on the activity of HRP. The amount of peroxidase required was r
educed 40- and 75-fold less than that required without PEG for 1 and 1
0 mM phenol solutions, respectively. The higher the phenol concentrati
on, the more effective was the addition of PEG. In the presence of PEG
, the optimum pH is 8.0 and the optimum molar ratio of hydrogen peroxi
de and phenol is around 1.0. The minimum doses of HRP and PEG required
for at least 95% removal were determined for several phenol concentra
tions and two empirical models are proposed to predict the minimum HRP
and PEG doses required for 95% removal over the entire phenol concent
ration range of 1-10 mM. Under the optimum reaction conditions describ
ed above, the reaction times for at least 95% removal from 1 and 10 mM
phenol solutions were 5 and 3h, respectively. An increase in HRP conc
entration significantly reduced the reaction time; however, an increas
e in PEG concentration showed negligible influence.