Survey on removing gentamicin antibiotic from aqueous media by recyclable magnetic titania photocatalyst

This work aims to study derivative removal of gentamicin (GMC) antibiotic from the aqueous solution within photocatalytic process using a recyclable magnetic titania (MT) photocatalyst. The MT photocatalyst was synthesised, characterised, and utilised by using co-precipitating method. The process of modelling and optimisation was performed by a second-order polynomial model. The ‘F-value’ of 432.56 and ‘P-value’ of 0.0001 indicated that the proposed model could be used for simulating the gentamicin photocatalytic removal process. According to the model prediction, the process could remove GMC antibiotic up to 94.7% in the optimum conditions (initial pH = 6.9, [GMC] = 20 ppm, MT dosage = 195 mg/L, and time = 63 min). Recycling and reusing potentials of the synthesised MT catalyst were studied in five cycles in the optimum conditions. According to the obtained results, in the first stage of catalyst recycling, the removal efficiency decreased by about 12%, but in the subsequent stages, the removal efficiency reduction was lower than the first step and about 5%. Mineralisation of the 51.3% efficiency was obtained in the optimum conditions. Kinetic study results showed that the data were well fitted by pseudo-first-order kinetic model with the regression coefficient of 0.9769. Also, the related reaction rate constant was 0.041 min−1. The effect of sulphate and chloride ions, as radical scavengers, on the removal efficiency demonstrated a reduction in GMC removal efficiency, which occurred by using chloride and sulphate ions. The results represented applying MT for treating real wastewater could remove GMC antibiotic in hospital wastewater up to 91.21%, too.