Abstract:
Photocatalysis is green technology for the degradation of recalcitrant organic compounds in water, and
have found success in the removal of several water pollutants. Degradation of pollutants is often
accompanied by their conversion into other compounds some of which are sometimes feared to be more
environmentally harmful than the parent compound. This study profiles aromatic intermediates formed
during photocatalytic degradation of phenol in a batch system. Catechol, hydroquinone and resorcinol
were identified as the major aromatic degradation intermediates. Maximum concentrations of
intermediates obtained is in the order catechol>resorcinol>hydroquinone with all three produced within the
first two minutes of phenol degradation. Resorcinol attained steady state concentration of 3.73 mg/L after 2
minutes of phenol photocatalysis with no appreciable change in its concentrations until all phenol is
degraded suggesting that production of resorcinol proceeds at approximately the same rate as its removal
from solution. Catechol formed rapidly attaining maximum concentration of 7.00 – 7.11 mg/L; after 6
minutes at a rate of 0.764 – 0.868 mg/L/min; decreasing thereafter at rates of 0.241 – 0.348 mg/L/min.
Maximum concentration of 0.96 – 1.66 mg/L; of hydroquinone was obtained then decreases steadily until
all phenol is degraded. Complete mineralisation of phenol and intermediates was achieved under optimum
reaction conditions.
