Profile of Aromatic Intermediates of Titanium Dioxide Mediated Degradation of Phenol

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