Removal of 4-chlorophenol by TiO2 suspansions and TiO2 immobilized polymer

The purpose of this study is the investigation of new catalyst systems for oxidative degradation of 4-chlorophenol (4-CP) that have been classified as first degree contaminants because of its high toxicity. Degradation of 4-CP (20 ppm) was investigated in aqueous heterogeneous catalyst system with a suspension of TiO2 and TiO2 loaded biodegradable polymer polycaprolactone (PCL). Photocatalytic method employing titanium dioxide (TiO2/UV) and silver-loaded titanium dioxide (Ag-TiO2/UV) was studied. The method optimization for suspension system was carried out for pH and contact time at constant TiO2 mass (2 g/L). Following this the adsorption ratios were determined in the absence of the light. The residual 4-CP was measured by employing standard 4-aminoantipyridine spectrophotometric method. Degradation ratio was calculated depending on exposure time and reaction conditions. It was found that 4-CP was successfully mineralized by Ag-TiO2 system. On the other hand, optimized pH conditions obtained above studies were used for polymer studies using TiO2 immobilized into the or onto the PCL. Additionally, the effect of the composite material mass and wavelength of the light source (?=254 nm ve 365 nm) were also investigated for degradation of 4-CP. Although degradation ratio was lower than suspension system it was possible to remove or degrade 4-CP with TiO2 immobilized PCL. Higher degradation ratios were observed with TiO2 immobilized onto PCL (%1).