Enhanced photocatalytic degradation of tetracycline and real pharmaceutical wastewater using MWCNT/TiO2 nano-composite

Photocatalytic degradation of tetracycline using MWCNT/TiO2nanocomposite was investigated under UVC irradiation. The effective operational parameters included pH, irradiation time, photocatalyst dosage, weight ratio of MWCNT to TiO2 and tetracycline concentration and were studied consecutively. Complete removal of tetracycline concentrations of up to 10 mg/L was obtained at MWCNT to TiO2 ratio of 1.5 (w/w%), pH 5, photocatalyst dosage of 0.2 g/L. Pseudo-first order kinetic model was best fitted with the experimental results (R2: 0.91-0.98 for different tetracycline concentrations). Based on TOC analysis, mineralization was 37% in the same reaction conditions for initial tetracycline concentration of 10 mg/L and reached to 83% after 300 min. In the case of real pharmaceutical wastewater, the COD concentration of 2267 mg/L decreased to 342 mg/L after 240 min in the same operational conditions.