Olive Mill Wastewater (OMW) Phenol Compounds Degradation by Means of a Visible Light Activated Titanium Dioxide-Based Photocatalyst

The use of titanium dioxide as heterogeneous photocatalyst is drawing considerable attention for water and air purification and remediation. Recently, TiO2 particles have been modified in order to make this material attractive for industrial and environmental remediation usage. In the present study, phenolic compounds of olive mill wastewater (OMW) were degraded in the presence of glucose-doped titanium particles (CDT) through a photocatalysis process activated by visible light. The photocatalyst effectiveness towards the polluted wastewater from olive oil industry was tested on systems having different initial concentrations of phenols and in the presence of different amounts of CDT. For kinetic analysis the role of Ti/TPh ratio (amount of catalyst/amount of total phenols) was investigated. The rate constant (k2) and the amounts of species adsorbed on adsorbent at equilibrium (qe) of each reaction were calculated by fitting kinetics data to a second-order kinetic adsorption model. The results collected at different Ti/TPh ratios showed that the amount of phenols that can be removed from the water solution linearly increases with the Ti/TPh ratio till a maximum value (optimal ratio) at which no further degradation of phenolic compounds was obtainable. Such kind of parameter allows to identify the optimal value of catalyst and the initial substrate concentration for a high level of degradation. The results showed in this study can have an important impact for an applicative point of view.